1 \input texinfo @c -*-texinfo-*-
3 @setfilename automake.info
10 @c @ovar(ARG, DEFAULT)
11 @c -------------------
12 @c The ARG is an optional argument. To be used for macro arguments in
13 @c their documentation (@defmac).
15 @r{[}@var{\varname\}@r{]}
18 @set PACKAGE_BUGREPORT bug-automake@@gnu.org
22 This manual is for GNU Automake (version @value{VERSION},
23 @value{UPDATED}), a program that creates GNU standards-compliant
24 Makefiles from template files.
26 Copyright @copyright{} 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
27 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software
31 Permission is granted to copy, distribute and/or modify this document
32 under the terms of the GNU Free Documentation License,
33 Version 1.3 or any later version published by the Free Software
34 Foundation; with no Invariant Sections, with no Front-Cover texts,
35 and with no Back-Cover Texts. A copy of the license is included in the
36 section entitled ``GNU Free Documentation License.''
41 @c info Automake points to the Automake package's documentation
42 @c info automake points to the automake script's documentation
43 @c (Autoconf has a similar setup.)
44 @dircategory Software development
46 * Automake: (automake). Making GNU standards-compliant Makefiles.
49 @dircategory Individual utilities
51 * aclocal: (automake)Invoking aclocal. Generating aclocal.m4.
52 * automake: (automake)Invoking Automake. Generating Makefile.in.
57 @subtitle For version @value{VERSION}, @value{UPDATED}
58 @author David MacKenzie
60 @author Alexandre Duret-Lutz
62 @vskip 0pt plus 1filll
68 @c We use the following macros to define indices:
69 @c @cindex concepts, and anything that does not fit elsewhere
70 @c @vindex Makefile variables
72 @c @acindex Autoconf/Automake/Libtool/M4/... macros
73 @c @opindex tool options
75 @c Define an index of configure macros.
77 @c Define an index of options.
79 @c Define an index of targets.
81 @c Define an index of commands.
84 @c Put the macros in the function index.
87 @c Put everything else into one index (arbitrarily chosen to be the
95 @comment node-name, next, previous, up
101 * Introduction:: Automake's purpose
102 * Autotools Introduction:: An Introduction to the Autotools
103 * Generalities:: General ideas
104 * Examples:: Some example packages
105 * Invoking Automake:: Creating a Makefile.in
106 * configure:: Scanning configure.ac, using aclocal
107 * Directories:: Declaring subdirectories
108 * Programs:: Building programs and libraries
109 * Other Objects:: Other derived objects
110 * Other GNU Tools:: Other GNU Tools
111 * Documentation:: Building documentation
112 * Install:: What gets installed
113 * Clean:: What gets cleaned
114 * Dist:: What goes in a distribution
115 * Tests:: Support for test suites
116 * Rebuilding:: Automatic rebuilding of Makefile
117 * Options:: Changing Automake's behavior
118 * Miscellaneous:: Miscellaneous rules
119 * Include:: Including extra files in an Automake template
120 * Conditionals:: Conditionals
121 * Silencing Make:: Obtain less verbose output from @command{make}
122 * Gnits:: The effect of @option{--gnu} and @option{--gnits}
123 * Cygnus:: The effect of @option{--cygnus}
124 * Not Enough:: When Automake is not Enough
125 * Distributing:: Distributing the Makefile.in
126 * API Versioning:: About compatibility between Automake versions
127 * Upgrading:: Upgrading to a Newer Automake Version
128 * FAQ:: Frequently Asked Questions
129 * History:: Notes about the history of Automake
130 * Copying This Manual:: How to make copies of this manual
131 * Indices:: Indices of variables, macros, and concepts
134 --- The Detailed Node Listing ---
136 An Introduction to the Autotools
138 * GNU Build System:: Introducing the GNU Build System
139 * Use Cases:: Use Cases for the GNU Build System
140 * Why Autotools:: How Autotools Help
141 * Hello World:: A Small Hello World Package
143 Use Cases for the GNU Build System
145 * Basic Installation:: Common installation procedure
146 * Standard Targets:: A list of standard Makefile targets
147 * Standard Directory Variables:: A list of standard directory variables
148 * Standard Configuration Variables:: Using configuration variables
149 * config.site:: Using a config.site file
150 * VPATH Builds:: Parallel build trees
151 * Two-Part Install:: Installing data and programs separately
152 * Cross-Compilation:: Building for other architectures
153 * Renaming:: Renaming programs at install time
154 * DESTDIR:: Building binary packages with DESTDIR
155 * Preparing Distributions:: Rolling out tarballs
156 * Dependency Tracking:: Automatic dependency tracking
157 * Nested Packages:: The GNU Build Systems can be nested
161 * Creating amhello:: Create @file{amhello-1.0.tar.gz} from scratch
162 * amhello's configure.ac Setup Explained::
163 * amhello's Makefile.am Setup Explained::
167 * General Operation:: General operation of Automake
168 * Strictness:: Standards conformance checking
169 * Uniform:: The Uniform Naming Scheme
170 * Length Limitations:: Staying below the command line length limit
171 * Canonicalization:: How derived variables are named
172 * User Variables:: Variables reserved for the user
173 * Auxiliary Programs:: Programs automake might require
175 Some example packages
177 * Complete:: A simple example, start to finish
178 * true:: Building true and false
180 Scanning @file{configure.ac}, using @command{aclocal}
182 * Requirements:: Configuration requirements
183 * Optional:: Other things Automake recognizes
184 * Invoking aclocal:: Auto-generating aclocal.m4
185 * Macros:: Autoconf macros supplied with Automake
187 Auto-generating aclocal.m4
189 * aclocal Options:: Options supported by aclocal
190 * Macro Search Path:: How aclocal finds .m4 files
191 * Extending aclocal:: Writing your own aclocal macros
192 * Local Macros:: Organizing local macros
193 * Serials:: Serial lines in Autoconf macros
194 * Future of aclocal:: aclocal's scheduled death
196 Autoconf macros supplied with Automake
198 * Public Macros:: Macros that you can use.
199 * Obsolete Macros:: Macros that you should stop using.
200 * Private Macros:: Macros that you should not use.
204 * Subdirectories:: Building subdirectories recursively
205 * Conditional Subdirectories:: Conditionally not building directories
206 * Alternative:: Subdirectories without recursion
207 * Subpackages:: Nesting packages
209 Conditional Subdirectories
211 * SUBDIRS vs DIST_SUBDIRS:: Two sets of directories
212 * Subdirectories with AM_CONDITIONAL:: Specifying conditional subdirectories
213 * Subdirectories with AC_SUBST:: Another way for conditional recursion
214 * Unconfigured Subdirectories:: Not even creating a @samp{Makefile}
216 Building Programs and Libraries
218 * A Program:: Building a program
219 * A Library:: Building a library
220 * A Shared Library:: Building a Libtool library
221 * Program and Library Variables:: Variables controlling program and
223 * Default _SOURCES:: Default source files
224 * LIBOBJS:: Special handling for LIBOBJS and ALLOCA
225 * Program Variables:: Variables used when building a program
226 * Yacc and Lex:: Yacc and Lex support
227 * C++ Support:: Compiling C++ sources
228 * Objective C Support:: Compiling Objective C sources
229 * Unified Parallel C Support:: Compiling Unified Parallel C sources
230 * Assembly Support:: Compiling assembly sources
231 * Fortran 77 Support:: Compiling Fortran 77 sources
232 * Fortran 9x Support:: Compiling Fortran 9x sources
233 * Java Support with gcj:: Compiling Java sources using gcj
234 * Vala Support:: Compiling Vala sources
235 * Support for Other Languages:: Compiling other languages
236 * ANSI:: Automatic de-ANSI-fication (deprecated, soon to be removed)
237 * Dependencies:: Automatic dependency tracking
238 * EXEEXT:: Support for executable extensions
242 * Program Sources:: Defining program sources
243 * Linking:: Linking with libraries or extra objects
244 * Conditional Sources:: Handling conditional sources
245 * Conditional Programs:: Building a program conditionally
247 Building a Shared Library
249 * Libtool Concept:: Introducing Libtool
250 * Libtool Libraries:: Declaring Libtool Libraries
251 * Conditional Libtool Libraries:: Building Libtool Libraries Conditionally
252 * Conditional Libtool Sources:: Choosing Library Sources Conditionally
253 * Libtool Convenience Libraries:: Building Convenience Libtool Libraries
254 * Libtool Modules:: Building Libtool Modules
255 * Libtool Flags:: Using _LIBADD, _LDFLAGS, and _LIBTOOLFLAGS
256 * LTLIBOBJS:: Using $(LTLIBOBJS) and $(LTALLOCA)
257 * Libtool Issues:: Common Issues Related to Libtool's Use
259 Common Issues Related to Libtool's Use
261 * Error required file ltmain.sh not found:: The need to run libtoolize
262 * Objects created both with libtool and without:: Avoid a specific build race
266 * Preprocessing Fortran 77:: Preprocessing Fortran 77 sources
267 * Compiling Fortran 77 Files:: Compiling Fortran 77 sources
268 * Mixing Fortran 77 With C and C++:: Mixing Fortran 77 With C and C++
270 Mixing Fortran 77 With C and C++
272 * How the Linker is Chosen:: Automatic linker selection
276 * Compiling Fortran 9x Files:: Compiling Fortran 9x sources
278 Other Derived Objects
280 * Scripts:: Executable scripts
281 * Headers:: Header files
282 * Data:: Architecture-independent data files
283 * Sources:: Derived sources
287 * Built Sources Example:: Several ways to handle built sources.
291 * Emacs Lisp:: Emacs Lisp
294 * Java:: Java bytecode compilation (deprecated)
297 Building documentation
300 * Man Pages:: Man pages
304 * Basics of Installation:: What gets installed where
305 * The Two Parts of Install:: Installing data and programs separately
306 * Extending Installation:: Adding your own rules for installation
307 * Staged Installs:: Installation in a temporary location
308 * Install Rules for the User:: Useful additional rules
310 What Goes in a Distribution
312 * Basics of Distribution:: Files distributed by default
313 * Fine-grained Distribution Control:: @code{dist_} and @code{nodist_} prefixes
314 * The dist Hook:: A target for last-minute distribution changes
315 * Checking the Distribution:: @samp{make distcheck} explained
316 * The Types of Distributions:: A variety of formats and compression methods
318 Support for test suites
320 * Simple Tests:: Listing programs and scripts in @code{TESTS}
321 * Simple Tests using parallel-tests:: More powerful test driver
322 * DejaGnu Tests:: Interfacing with the external testing framework
323 * Install Tests:: Running tests on installed packages
327 * Tags:: Interfacing to etags and mkid
328 * Suffixes:: Handling new file extensions
329 * Multilibs:: Support for multilibs.
333 * Usage of Conditionals:: Declaring conditional content
334 * Limits of Conditionals:: Enclosing complete statements
338 * Make verbosity:: Make is verbose by default
339 * Tricks For Silencing Make:: Standard and generic ways to silence make
340 * Automake silent-rules Option:: How Automake can help in silencing make
342 When Automake Isn't Enough
344 * Extending:: Adding new rules or overriding existing ones.
345 * Third-Party Makefiles:: Integrating Non-Automake @file{Makefile}s.
347 Frequently Asked Questions about Automake
349 * CVS:: CVS and generated files
350 * maintainer-mode:: missing and AM_MAINTAINER_MODE
351 * Wildcards:: Why doesn't Automake support wildcards?
352 * Limitations on File Names:: Limitations on source and installed file names
353 * distcleancheck:: Files left in build directory after distclean
354 * Flag Variables Ordering:: CFLAGS vs.@: AM_CFLAGS vs.@: mumble_CFLAGS
355 * Renamed Objects:: Why are object files sometimes renamed?
356 * Per-Object Flags:: How to simulate per-object flags?
357 * Multiple Outputs:: Writing rules for tools with many output files
358 * Hard-Coded Install Paths:: Installing to hard-coded locations
359 * Debugging Make Rules:: Strategies when things don't work as expected
360 * Reporting Bugs:: Feedback on bugs and feature requests
364 * Timeline:: The Automake story.
365 * Dependency Tracking Evolution:: Evolution of Automatic Dependency Tracking
366 * Releases:: Statistics about Automake Releases
368 Dependency Tracking in Automake
370 * First Take on Dependencies:: Precomputed dependency tracking
371 * Dependencies As Side Effects:: Update at developer compile time
372 * Dependencies for the User:: Update at user compile time
373 * Techniques for Dependencies:: Alternative approaches
374 * Recommendations for Tool Writers:: What tool writers can do to help
375 * Future Directions for Dependencies:: Languages Automake does not know
379 * GNU Free Documentation License:: License for copying this manual
383 * Macro Index:: Index of Autoconf macros
384 * Variable Index:: Index of Makefile variables
385 * General Index:: General index
394 @chapter Introduction
396 Automake is a tool for automatically generating @file{Makefile.in}s
397 from files called @file{Makefile.am}. Each @file{Makefile.am} is
398 basically a series of @command{make} variable
399 definitions@footnote{These variables are also called @dfn{make macros}
400 in Make terminology, however in this manual we reserve the term
401 @dfn{macro} for Autoconf's macros.}, with rules being thrown in
402 occasionally. The generated @file{Makefile.in}s are compliant with
403 the GNU Makefile standards.
405 @cindex GNU Makefile standards
407 The GNU Makefile Standards Document
408 (@pxref{Makefile Conventions, , , standards, The GNU Coding Standards})
409 is long, complicated, and subject to change. The goal of Automake is to
410 remove the burden of Makefile maintenance from the back of the
411 individual GNU maintainer (and put it on the back of the Automake
414 The typical Automake input file is simply a series of variable definitions.
415 Each such file is processed to create a @file{Makefile.in}. There
416 should generally be one @file{Makefile.am} per directory of a project.
418 @cindex Constraints of Automake
419 @cindex Automake constraints
421 Automake does constrain a project in certain ways; for instance, it
422 assumes that the project uses Autoconf (@pxref{Top, , Introduction,
423 autoconf, The Autoconf Manual}), and enforces certain restrictions on
424 the @file{configure.ac} contents@footnote{Older Autoconf versions used
425 @file{configure.in}. Autoconf 2.50 and greater promotes
426 @file{configure.ac} over @file{configure.in}. The rest of this
427 documentation will refer to @file{configure.ac}, but Automake also
428 supports @file{configure.in} for backward compatibility.}.
430 @cindex Automake requirements
431 @cindex Requirements, Automake
433 Automake requires @command{perl} in order to generate the
434 @file{Makefile.in}s. However, the distributions created by Automake are
435 fully GNU standards-compliant, and do not require @command{perl} in order
438 @cindex Bugs, reporting
439 @cindex Reporting bugs
440 @cindex E-mail, bug reports
442 For more information on bug reports, @xref{Reporting Bugs}.
444 @node Autotools Introduction
445 @chapter An Introduction to the Autotools
447 If you are new to Automake, maybe you know that it is part of a set of
448 tools called @emph{The Autotools}. Maybe you've already delved into a
449 package full of files named @file{configure}, @file{configure.ac},
450 @file{Makefile.in}, @file{Makefile.am}, @file{aclocal.m4}, @dots{},
451 some of them claiming to be @emph{generated by} Autoconf or Automake.
452 But the exact purpose of these files and their relations is probably
453 fuzzy. The goal of this chapter is to introduce you to this machinery,
454 to show you how it works and how powerful it is. If you've never
455 installed or seen such a package, do not worry: this chapter will walk
458 If you need some teaching material, more illustrations, or a less
459 @command{automake}-centered continuation, some slides for this
460 introduction are available in Alexandre Duret-Lutz's
461 @uref{http://www.lrde.epita.fr/@/~adl/@/autotools.html,
463 This chapter is the written version of the first part of his tutorial.
466 * GNU Build System:: Introducing the GNU Build System
467 * Use Cases:: Use Cases for the GNU Build System
468 * Why Autotools:: How Autotools Help
469 * Hello World:: A Small Hello World Package
472 @node GNU Build System
473 @section Introducing the GNU Build System
474 @cindex GNU Build System, introduction
476 It is a truth universally acknowledged, that as a developer in
477 possession of a new package, you must be in want of a build system.
479 In the Unix world, such a build system is traditionally achieved using
480 the command @command{make} (@pxref{Top, , Overview, make, The GNU Make
481 Manual}). You express the recipe to build your package in a
482 @file{Makefile}. This file is a set of rules to build the files in
483 the package. For instance the program @file{prog} may be built by
484 running the linker on the files @file{main.o}, @file{foo.o}, and
485 @file{bar.o}; the file @file{main.o} may be built by running the
486 compiler on @file{main.c}; etc. Each time @command{make} is run, it
487 reads @file{Makefile}, checks the existence and modification time of
488 the files mentioned, decides what files need to be built (or rebuilt),
489 and runs the associated commands.
491 When a package needs to be built on a different platform than the one
492 it was developed on, its @file{Makefile} usually needs to be adjusted.
493 For instance the compiler may have another name or require more
494 options. In 1991, David J. MacKenzie got tired of customizing
495 @file{Makefile} for the 20 platforms he had to deal with. Instead, he
496 handcrafted a little shell script called @file{configure} to
497 automatically adjust the @file{Makefile} (@pxref{Genesis, , Genesis,
498 autoconf, The Autoconf Manual}). Compiling his package was now
499 as simple as running @code{./configure && make}.
501 @cindex GNU Coding Standards
503 Today this process has been standardized in the GNU project. The GNU
504 Coding Standards (@pxref{Managing Releases, The Release Process, ,
505 standards, The GNU Coding Standards}) explains how each package of the
506 GNU project should have a @file{configure} script, and the minimal
507 interface it should have. The @file{Makefile} too should follow some
508 established conventions. The result? A unified build system that
509 makes all packages almost indistinguishable by the installer. In its
510 simplest scenario, all the installer has to do is to unpack the
511 package, run @code{./configure && make && make install}, and repeat
512 with the next package to install.
514 We call this build system the @dfn{GNU Build System}, since it was
515 grown out of the GNU project. However it is used by a vast number of
516 other packages: following any existing convention has its advantages.
518 @cindex Autotools, introduction
520 The Autotools are tools that will create a GNU Build System for your
521 package. Autoconf mostly focuses on @file{configure} and Automake on
522 @file{Makefile}s. It is entirely possible to create a GNU Build
523 System without the help of these tools. However it is rather
524 burdensome and error-prone. We will discuss this again after some
525 illustration of the GNU Build System in action.
528 @section Use Cases for the GNU Build System
529 @cindex GNU Build System, use cases
530 @cindex GNU Build System, features
531 @cindex Features of the GNU Build System
532 @cindex Use Cases for the GNU Build System
533 @cindex @file{amhello-1.0.tar.gz}, location
534 @cindex @file{amhello-1.0.tar.gz}, use cases
536 In this section we explore several use cases for the GNU Build System.
537 You can replay all these examples on the @file{amhello-1.0.tar.gz}
538 package distributed with Automake. If Automake is installed on your
539 system, you should find a copy of this file in
540 @file{@var{prefix}/share/doc/automake/amhello-1.0.tar.gz}, where
541 @var{prefix} is the installation prefix specified during configuration
542 (@var{prefix} defaults to @file{/usr/local}, however if Automake was
543 installed by some GNU/Linux distribution it most likely has been set
544 to @file{/usr}). If you do not have a copy of Automake installed,
545 you can find a copy of this file inside the @file{doc/} directory of
546 the Automake package.
548 Some of the following use cases present features that are in fact
549 extensions to the GNU Build System. Read: they are not specified by
550 the GNU Coding Standards, but they are nonetheless part of the build
551 system created by the Autotools. To keep things simple, we do not
552 point out the difference. Our objective is to show you many of the
553 features that the build system created by the Autotools will offer to
557 * Basic Installation:: Common installation procedure
558 * Standard Targets:: A list of standard Makefile targets
559 * Standard Directory Variables:: A list of standard directory variables
560 * Standard Configuration Variables:: Using configuration variables
561 * config.site:: Using a config.site file
562 * VPATH Builds:: Parallel build trees
563 * Two-Part Install:: Installing data and programs separately
564 * Cross-Compilation:: Building for other architectures
565 * Renaming:: Renaming programs at install time
566 * DESTDIR:: Building binary packages with DESTDIR
567 * Preparing Distributions:: Rolling out tarballs
568 * Dependency Tracking:: Automatic dependency tracking
569 * Nested Packages:: The GNU Build Systems can be nested
572 @node Basic Installation
573 @subsection Basic Installation
574 @cindex Configuration, basics
575 @cindex Installation, basics
576 @cindex GNU Build System, basics
578 The most common installation procedure looks as follows.
581 ~ % @kbd{tar zxf amhello-1.0.tar.gz}
582 ~ % @kbd{cd amhello-1.0}
583 ~/amhello-1.0 % @kbd{./configure}
585 config.status: creating Makefile
586 config.status: creating src/Makefile
588 ~/amhello-1.0 % @kbd{make}
590 ~/amhello-1.0 % @kbd{make check}
592 ~/amhello-1.0 % @kbd{su}
594 /home/adl/amhello-1.0 # @kbd{make install}
596 /home/adl/amhello-1.0 # @kbd{exit}
597 ~/amhello-1.0 % @kbd{make installcheck}
603 The user first unpacks the package. Here, and in the following
604 examples, we will use the non-portable @code{tar zxf} command for
605 simplicity. On a system without GNU @command{tar} installed, this
606 command should read @code{gunzip -c amhello-1.0.tar.gz | tar xf -}.
608 The user then enters the newly created directory to run the
609 @file{configure} script. This script probes the system for various
610 features, and finally creates the @file{Makefile}s. In this toy
611 example there are only two @file{Makefile}s, but in real-world projects,
612 there may be many more, usually one @file{Makefile} per directory.
614 It is now possible to run @code{make}. This will construct all the
615 programs, libraries, and scripts that need to be constructed for the
616 package. In our example, this compiles the @file{hello} program.
617 All files are constructed in place, in the source tree; we will see
618 later how this can be changed.
620 @code{make check} causes the package's tests to be run. This step is
621 not mandatory, but it is often good to make sure the programs that
622 have been built behave as they should, before you decide to install
623 them. Our example does not contain any tests, so running @code{make
626 @cindex su, before @code{make install}
627 After everything has been built, and maybe tested, it is time to
628 install it on the system. That means copying the programs,
629 libraries, header files, scripts, and other data files from the
630 source directory to their final destination on the system. The
631 command @code{make install} will do that. However, by default
632 everything will be installed in subdirectories of @file{/usr/local}:
633 binaries will go into @file{/usr/local/bin}, libraries will end up in
634 @file{/usr/local/lib}, etc. This destination is usually not writable
635 by any user, so we assume that we have to become root before we can
636 run @code{make install}. In our example, running @code{make install}
637 will copy the program @file{hello} into @file{/usr/local/bin}
638 and @file{README} into @file{/usr/local/share/doc/amhello}.
640 A last and optional step is to run @code{make installcheck}. This
641 command may run tests on the installed files. @code{make check} tests
642 the files in the source tree, while @code{make installcheck} tests
643 their installed copies. The tests run by the latter can be different
644 from those run by the former. For instance, there are tests that
645 cannot be run in the source tree. Conversely, some packages are set
646 up so that @code{make installcheck} will run the very same tests as
647 @code{make check}, only on different files (non-installed
648 vs.@: installed). It can make a difference, for instance when the
649 source tree's layout is different from that of the installation.
650 Furthermore it may help to diagnose an incomplete installation.
652 Presently most packages do not have any @code{installcheck} tests
653 because the existence of @code{installcheck} is little known, and its
654 usefulness is neglected. Our little toy package is no better: @code{make
655 installcheck} does nothing.
657 @node Standard Targets
658 @subsection Standard @file{Makefile} Targets
660 So far we have come across four ways to run @command{make} in the GNU
661 Build System: @code{make}, @code{make check}, @code{make install}, and
662 @code{make installcheck}. The words @code{check}, @code{install}, and
663 @code{installcheck}, passed as arguments to @command{make}, are called
664 @dfn{targets}. @code{make} is a shorthand for @code{make all},
665 @code{all} being the default target in the GNU Build System.
667 Here is a list of the most useful targets that the GNU Coding Standards
673 Build programs, libraries, documentation, etc.@: (same as @code{make}).
676 Install what needs to be installed, copying the files from the
677 package's tree to system-wide directories.
678 @item make install-strip
679 @trindex install-strip
680 Same as @code{make install}, then strip debugging symbols. Some
681 users like to trade space for useful bug reports@enddots{}
684 The opposite of @code{make install}: erase the installed files.
685 (This needs to be run from the same build tree that was installed.)
688 Erase from the build tree the files built by @code{make all}.
691 Additionally erase anything @code{./configure} created.
694 Run the test suite, if any.
695 @item make installcheck
696 @trindex installcheck
697 Check the installed programs or libraries, if supported.
700 Recreate @file{@var{package}-@var{version}.tar.gz} from all the source
704 @node Standard Directory Variables
705 @subsection Standard Directory Variables
706 @cindex directory variables
708 The GNU Coding Standards also specify a hierarchy of variables to
709 denote installation directories. Some of these are:
711 @multitable {Directory variable} {@code{$@{datarootdir@}/doc/$@{PACKAGE@}}}
712 @headitem Directory variable @tab Default value
713 @item @code{prefix} @tab @code{/usr/local}
714 @item @w{@ @ @code{exec_prefix}} @tab @code{$@{prefix@}}
715 @item @w{@ @ @ @ @code{bindir}} @tab @code{$@{exec_prefix@}/bin}
716 @item @w{@ @ @ @ @code{libdir}} @tab @code{$@{exec_prefix@}/lib}
717 @item @w{@ @ @ @ @dots{}}
718 @item @w{@ @ @code{includedir}} @tab @code{$@{prefix@}/include}
719 @item @w{@ @ @code{datarootdir}} @tab @code{$@{prefix@}/share}
720 @item @w{@ @ @ @ @code{datadir}} @tab @code{$@{datarootdir@}}
721 @item @w{@ @ @ @ @code{mandir}} @tab @code{$@{datarootdir@}/man}
722 @item @w{@ @ @ @ @code{infodir}} @tab @code{$@{datarootdir@}/info}
723 @item @w{@ @ @ @ @code{docdir}} @tab @code{$@{datarootdir@}/doc/$@{PACKAGE@}}
724 @item @w{@ @ @dots{}}
727 @c We should provide a complete table somewhere, but not here. The
728 @c complete list of directory variables it too confusing as-is. It
729 @c requires some explanations that are too complicated for this
730 @c introduction. Besides listing directories like localstatedir
731 @c would make the explanations in ``Two-Part Install'' harder.
733 Each of these directories has a role which is often obvious from its
734 name. In a package, any installable file will be installed in one of
735 these directories. For instance in @code{amhello-1.0}, the program
736 @file{hello} is to be installed in @var{bindir}, the directory for
737 binaries. The default value for this directory is
738 @file{/usr/local/bin}, but the user can supply a different value when
739 calling @command{configure}. Also the file @file{README} will be
740 installed into @var{docdir}, which defaults to
741 @file{/usr/local/share/doc/amhello}.
745 As a user, if you wish to install a package on your own account, you
746 could proceed as follows:
749 ~/amhello-1.0 % @kbd{./configure --prefix ~/usr}
751 ~/amhello-1.0 % @kbd{make}
753 ~/amhello-1.0 % @kbd{make install}
757 This would install @file{~/usr/bin/hello} and
758 @file{~/usr/share/doc/amhello/README}.
760 The list of all such directory options is shown by
761 @code{./configure --help}.
763 @node Standard Configuration Variables
764 @subsection Standard Configuration Variables
765 @cindex configuration variables, overriding
767 The GNU Coding Standards also define a set of standard configuration
768 variables used during the build. Here are some:
777 @item @code{CXXFLAGS}
781 @item @code{CPPFLAGS}
782 C/C++ preprocessor flags
786 @command{configure} usually does a good job at setting appropriate
787 values for these variables, but there are cases where you may want to
788 override them. For instance you may have several versions of a
789 compiler installed and would like to use another one, you may have
790 header files installed outside the default search path of the
791 compiler, or even libraries out of the way of the linker.
793 Here is how one would call @command{configure} to force it to use
794 @command{gcc-3} as C compiler, use header files from
795 @file{~/usr/include} when compiling, and libraries from
796 @file{~/usr/lib} when linking.
799 ~/amhello-1.0 % @kbd{./configure --prefix ~/usr CC=gcc-3 \
800 CPPFLAGS=-I$HOME/usr/include LDFLAGS=-L$HOME/usr/lib}
803 Again, a full list of these variables appears in the output of
804 @code{./configure --help}.
807 @subsection Overriding Default Configuration Setting with @file{config.site}
808 @cindex @file{config.site} example
810 When installing several packages using the same setup, it can be
811 convenient to create a file to capture common settings.
812 If a file named @file{@var{prefix}/share/config.site} exists,
813 @command{configure} will source it at the beginning of its execution.
815 Recall the command from the previous section:
818 ~/amhello-1.0 % @kbd{./configure --prefix ~/usr CC=gcc-3 \
819 CPPFLAGS=-I$HOME/usr/include LDFLAGS=-L$HOME/usr/lib}
822 Assuming we are installing many package in @file{~/usr}, and will
823 always want to use these definitions of @code{CC}, @code{CPPFLAGS}, and
824 @code{LDFLAGS}, we can automate this by creating the following
825 @file{~/usr/share/config.site} file:
828 test -z "$CC" && CC=gcc-3
829 test -z "$CPPFLAGS" && CPPFLAGS=-I$HOME/usr/include
830 test -z "$LDFLAGS" && LDFLAGS=-L$HOME/usr/lib
833 Now, any time a @file{configure} script is using the @file{~/usr}
834 prefix, it will execute the above @file{config.site} and define
835 these three variables.
838 ~/amhello-1.0 % @kbd{./configure --prefix ~/usr}
839 configure: loading site script /home/adl/usr/share/config.site
843 @xref{Site Defaults, , Setting Site Defaults, autoconf, The Autoconf
844 Manual}, for more information about this feature.
848 @subsection Parallel Build Trees (a.k.a.@: VPATH Builds)
849 @cindex Parallel build trees
851 @cindex source tree and build tree
852 @cindex build tree and source tree
853 @cindex trees, source vs.@: build
855 The GNU Build System distinguishes two trees: the source tree, and
858 The source tree is rooted in the directory containing
859 @file{configure}. It contains all the sources files (those that are
860 distributed), and may be arranged using several subdirectories.
862 The build tree is rooted in the directory in which @file{configure}
863 was run, and is populated with all object files, programs, libraries,
864 and other derived files built from the sources (and hence not
865 distributed). The build tree usually has the same subdirectory layout
866 as the source tree; its subdirectories are created automatically by
869 If @file{configure} is executed in its own directory, the source and
870 build trees are combined: derived files are constructed in the same
871 directories as their sources. This was the case in our first
872 installation example (@pxref{Basic Installation}).
874 A common request from users is that they want to confine all derived
875 files to a single directory, to keep their source directories
876 uncluttered. Here is how we could run @file{configure} to build
877 everything in a subdirectory called @file{build/}.
880 ~ % @kbd{tar zxf ~/amhello-1.0.tar.gz}
881 ~ % @kbd{cd amhello-1.0}
882 ~/amhello-1.0 % @kbd{mkdir build && cd build}
883 ~/amhello-1.0/build % @kbd{../configure}
885 ~/amhello-1.0/build % @kbd{make}
889 These setups, where source and build trees are different, are often
890 called @dfn{parallel builds} or @dfn{VPATH builds}. The expression
891 @emph{parallel build} is misleading: the word @emph{parallel} is a
892 reference to the way the build tree shadows the source tree, it is not
893 about some concurrency in the way build commands are run. For this
894 reason we refer to such setups using the name @emph{VPATH builds} in
895 the following. @emph{VPATH} is the name of the @command{make} feature
896 used by the @file{Makefile}s to allow these builds (@pxref{General
897 Search, , @code{VPATH} Search Path for All Prerequisites, make, The
900 @cindex multiple configurations, example
901 @cindex debug build, example
902 @cindex optimized build, example
904 VPATH builds have other interesting uses. One is to build the same
905 sources with multiple configurations. For instance:
907 @c Keep in sync with amhello-cflags.test.
909 ~ % @kbd{tar zxf ~/amhello-1.0.tar.gz}
910 ~ % @kbd{cd amhello-1.0}
911 ~/amhello-1.0 % @kbd{mkdir debug optim && cd debug}
912 ~/amhello-1.0/debug % @kbd{../configure CFLAGS='-g -O0'}
914 ~/amhello-1.0/debug % @kbd{make}
916 ~/amhello-1.0/debug % cd ../optim
917 ~/amhello-1.0/optim % @kbd{../configure CFLAGS='-O3 -fomit-frame-pointer'}
919 ~/amhello-1.0/optim % @kbd{make}
923 With network file systems, a similar approach can be used to build the
924 same sources on different machines. For instance, suppose that the
925 sources are installed on a directory shared by two hosts: @code{HOST1}
926 and @code{HOST2}, which may be different platforms.
929 ~ % @kbd{cd /nfs/src}
930 /nfs/src % @kbd{tar zxf ~/amhello-1.0.tar.gz}
933 On the first host, you could create a local build directory:
935 [HOST1] ~ % @kbd{mkdir /tmp/amh && cd /tmp/amh}
936 [HOST1] /tmp/amh % @kbd{/nfs/src/amhello-1.0/configure}
938 [HOST1] /tmp/amh % @kbd{make && sudo make install}
943 (Here we assume that the installer has configured @command{sudo} so it
944 can execute @code{make install} with root privileges; it is more convenient
945 than using @command{su} like in @ref{Basic Installation}).
947 On the second host, you would do exactly the same, possibly at
950 [HOST2] ~ % @kbd{mkdir /tmp/amh && cd /tmp/amh}
951 [HOST2] /tmp/amh % @kbd{/nfs/src/amhello-1.0/configure}
953 [HOST2] /tmp/amh % @kbd{make && sudo make install}
957 @cindex read-only source tree
958 @cindex source tree, read-only
960 In this scenario, nothing forbids the @file{/nfs/src/amhello-1.0}
961 directory from being read-only. In fact VPATH builds are also a means
962 of building packages from a read-only medium such as a CD-ROM. (The
963 FSF used to sell CD-ROM with unpacked source code, before the GNU
964 project grew so big.)
966 @node Two-Part Install
967 @subsection Two-Part Installation
969 In our last example (@pxref{VPATH Builds}), a source tree was shared
970 by two hosts, but compilation and installation were done separately on
973 The GNU Build System also supports networked setups where part of the
974 installed files should be shared amongst multiple hosts. It does so
975 by distinguishing architecture-dependent files from
976 architecture-independent files, and providing two @file{Makefile}
977 targets to install each of these classes of files.
979 @trindex install-exec
980 @trindex install-data
982 These targets are @code{install-exec} for architecture-dependent files
983 and @code{install-data} for architecture-independent files.
984 The command we used up to now, @code{make install}, can be thought of
985 as a shorthand for @code{make install-exec install-data}.
987 From the GNU Build System point of view, the distinction between
988 architecture-dependent files and architecture-independent files is
989 based exclusively on the directory variable used to specify their
990 installation destination. In the list of directory variables we
991 provided earlier (@pxref{Standard Directory Variables}), all the
992 variables based on @var{exec-prefix} designate architecture-dependent
993 directories whose files will be installed by @code{make install-exec}.
994 The others designate architecture-independent directories and will
995 serve files installed by @code{make install-data}. @xref{The Two Parts
996 of Install}, for more details.
998 Here is how we could revisit our two-host installation example,
999 assuming that (1) we want to install the package directly in
1000 @file{/usr}, and (2) the directory @file{/usr/share} is shared by the
1003 On the first host we would run
1005 [HOST1] ~ % @kbd{mkdir /tmp/amh && cd /tmp/amh}
1006 [HOST1] /tmp/amh % @kbd{/nfs/src/amhello-1.0/configure --prefix /usr}
1008 [HOST1] /tmp/amh % @kbd{make && sudo make install}
1012 On the second host, however, we need only install the
1013 architecture-specific files.
1015 [HOST2] ~ % @kbd{mkdir /tmp/amh && cd /tmp/amh}
1016 [HOST2] /tmp/amh % @kbd{/nfs/src/amhello-1.0/configure --prefix /usr}
1018 [HOST2] /tmp/amh % @kbd{make && sudo make install-exec}
1022 In packages that have installation checks, it would make sense to run
1023 @code{make installcheck} (@pxref{Basic Installation}) to verify that
1024 the package works correctly despite the apparent partial installation.
1026 @node Cross-Compilation
1027 @subsection Cross-Compilation
1028 @cindex cross-compilation
1030 To @dfn{cross-compile} is to build on one platform a binary that will
1031 run on another platform. When speaking of cross-compilation, it is
1032 important to distinguish between the @dfn{build platform} on which
1033 the compilation is performed, and the @dfn{host platform} on which the
1034 resulting executable is expected to run. The following
1035 @command{configure} options are used to specify each of them:
1038 @item --build=@var{build}
1039 @opindex --build=@var{build}
1040 The system on which the package is built.
1041 @item --host=@var{host}
1042 @opindex --host=@var{host}
1043 The system where built programs and libraries will run.
1046 When the @option{--host} is used, @command{configure} will search for
1047 the cross-compiling suite for this platform. Cross-compilation tools
1048 commonly have their target architecture as prefix of their name. For
1049 instance my cross-compiler for MinGW32 has its binaries called
1050 @code{i586-mingw32msvc-gcc}, @code{i586-mingw32msvc-ld},
1051 @code{i586-mingw32msvc-as}, etc.
1053 @cindex MinGW cross-compilation example
1054 @cindex cross-compilation example
1056 Here is how we could build @code{amhello-1.0} for
1057 @code{i586-mingw32msvc} on a GNU/Linux PC.
1059 @c Keep in sync with amhello-cross-compile.test.
1061 ~/amhello-1.0 % @kbd{./configure --build i686-pc-linux-gnu --host i586-mingw32msvc}
1062 checking for a BSD-compatible install... /usr/bin/install -c
1063 checking whether build environment is sane... yes
1064 checking for gawk... gawk
1065 checking whether make sets $(MAKE)... yes
1066 checking for i586-mingw32msvc-strip... i586-mingw32msvc-strip
1067 checking for i586-mingw32msvc-gcc... i586-mingw32msvc-gcc
1068 checking for C compiler default output file name... a.exe
1069 checking whether the C compiler works... yes
1070 checking whether we are cross compiling... yes
1071 checking for suffix of executables... .exe
1072 checking for suffix of object files... o
1073 checking whether we are using the GNU C compiler... yes
1074 checking whether i586-mingw32msvc-gcc accepts -g... yes
1075 checking for i586-mingw32msvc-gcc option to accept ANSI C...
1077 ~/amhello-1.0 % @kbd{make}
1079 ~/amhello-1.0 % @kbd{cd src; file hello.exe}
1080 hello.exe: MS Windows PE 32-bit Intel 80386 console executable not relocatable
1083 The @option{--host} and @option{--build} options are usually all we
1084 need for cross-compiling. The only exception is if the package being
1085 built is itself a cross-compiler: we need a third option to specify
1086 its target architecture.
1089 @item --target=@var{target}
1090 @opindex --target=@var{target}
1091 When building compiler tools: the system for which the tools will
1095 For instance when installing GCC, the GNU Compiler Collection, we can
1096 use @option{--target=@/@var{target}} to specify that we want to build
1097 GCC as a cross-compiler for @var{target}. Mixing @option{--build} and
1098 @option{--target}, we can actually cross-compile a cross-compiler;
1099 such a three-way cross-compilation is known as a @dfn{Canadian cross}.
1101 @xref{Specifying Names, , Specifying the System Type, autoconf, The
1102 Autoconf Manual}, for more information about these @command{configure}
1106 @subsection Renaming Programs at Install Time
1107 @cindex Renaming programs
1108 @cindex Transforming program names
1109 @cindex Programs, renaming during installation
1111 The GNU Build System provides means to automatically rename
1112 executables and manpages before they are installed (@pxref{Man Pages}).
1113 This is especially convenient
1114 when installing a GNU package on a system that already has a
1115 proprietary implementation you do not want to overwrite. For instance,
1116 you may want to install GNU @command{tar} as @command{gtar} so you can
1117 distinguish it from your vendor's @command{tar}.
1119 This can be done using one of these three @command{configure} options.
1122 @item --program-prefix=@var{prefix}
1123 @opindex --program-prefix=@var{prefix}
1124 Prepend @var{prefix} to installed program names.
1125 @item --program-suffix=@var{suffix}
1126 @opindex --program-suffix=@var{suffix}
1127 Append @var{suffix} to installed program names.
1128 @item --program-transform-name=@var{program}
1129 @opindex --program-transform-name=@var{program}
1130 Run @code{sed @var{program}} on installed program names.
1133 The following commands would install @file{hello}
1134 as @file{/usr/local/bin/test-hello}, for instance.
1137 ~/amhello-1.0 % @kbd{./configure --program-prefix test-}
1139 ~/amhello-1.0 % @kbd{make}
1141 ~/amhello-1.0 % @kbd{sudo make install}
1146 @subsection Building Binary Packages Using DESTDIR
1149 The GNU Build System's @code{make install} and @code{make uninstall}
1150 interface does not exactly fit the needs of a system administrator
1151 who has to deploy and upgrade packages on lots of hosts. In other
1152 words, the GNU Build System does not replace a package manager.
1154 Such package managers usually need to know which files have been
1155 installed by a package, so a mere @code{make install} is
1158 @cindex Staged installation
1160 The @code{DESTDIR} variable can be used to perform a staged
1161 installation. The package should be configured as if it was going to
1162 be installed in its final location (e.g., @code{--prefix /usr}), but
1163 when running @code{make install}, the @code{DESTDIR} should be set to
1164 the absolute name of a directory into which the installation will be
1165 diverted. From this directory it is easy to review which files are
1166 being installed where, and finally copy them to their final location
1169 @cindex Binary package
1171 For instance here is how we could create a binary package containing a
1172 snapshot of all the files to be installed.
1174 @c Keep in sync with amhello-binpkg.test.
1176 ~/amhello-1.0 % @kbd{./configure --prefix /usr}
1178 ~/amhello-1.0 % @kbd{make}
1180 ~/amhello-1.0 % @kbd{make DESTDIR=$HOME/inst install}
1182 ~/amhello-1.0 % @kbd{cd ~/inst}
1183 ~/inst % @kbd{find . -type f -print > ../files.lst}
1184 ~/inst % @kbd{tar zcvf ~/amhello-1.0-i686.tar.gz `cat ../files.lst`}
1186 ./usr/share/doc/amhello/README
1189 After this example, @code{amhello-1.0-i686.tar.gz} is ready to be
1190 uncompressed in @file{/} on many hosts. (Using @code{`cat ../files.lst`}
1191 instead of @samp{.} as argument for @command{tar} avoids entries for
1192 each subdirectory in the archive: we would not like @command{tar} to
1193 restore the modification time of @file{/}, @file{/usr/}, etc.)
1195 Note that when building packages for several architectures, it might
1196 be convenient to use @code{make install-data} and @code{make
1197 install-exec} (@pxref{Two-Part Install}) to gather
1198 architecture-independent files in a single package.
1200 @xref{Install}, for more information.
1202 @c We should document PRE_INSTALL/POST_INSTALL/NORMAL_INSTALL and their
1203 @c UNINSTALL counterparts.
1205 @node Preparing Distributions
1206 @subsection Preparing Distributions
1207 @cindex Preparing distributions
1208 @cindex Packages, preparation
1209 @cindex Distributions, preparation
1211 We have already mentioned @code{make dist}. This target collects all
1212 your source files and the necessary parts of the build system to
1213 create a tarball named @file{@var{package}-@var{version}.tar.gz}.
1215 @cindex @code{distcheck} better than @code{dist}
1217 Another, more useful command is @code{make distcheck}. The
1218 @code{distcheck} target constructs
1219 @file{@var{package}-@var{version}.tar.gz} just as well as @code{dist},
1220 but it additionally ensures most of the use cases presented so far
1225 It attempts a full compilation of the package (@pxref{Basic
1226 Installation}), unpacking the newly constructed tarball, running
1227 @code{make}, @code{make check}, @code{make install}, as well as
1228 @code{make installcheck}, and even @code{make dist},
1230 it tests VPATH builds with read-only source tree (@pxref{VPATH Builds}),
1232 it makes sure @code{make clean}, @code{make distclean}, and @code{make
1233 uninstall} do not omit any file (@pxref{Standard Targets}),
1235 and it checks that @code{DESTDIR} installations work (@pxref{DESTDIR}).
1238 All of these actions are performed in a temporary subdirectory, so
1239 that no root privileges are required.
1241 Releasing a package that fails @code{make distcheck} means that one of
1242 the scenarios we presented will not work and some users will be
1243 disappointed. Therefore it is a good practice to release a package
1244 only after a successful @code{make distcheck}. This of course does
1245 not imply that the package will be flawless, but at least it will
1246 prevent some of the embarrassing errors you may find in packages
1247 released by people who have never heard about @code{distcheck} (like
1248 @code{DESTDIR} not working because of a typo, or a distributed file
1249 being erased by @code{make clean}, or even @code{VPATH} builds not
1252 @xref{Creating amhello}, to recreate @file{amhello-1.0.tar.gz} using
1253 @code{make distcheck}. @xref{Checking the Distribution}, for more
1254 information about @code{distcheck}.
1256 @node Dependency Tracking
1257 @subsection Automatic Dependency Tracking
1258 @cindex Dependency tracking
1260 Dependency tracking is performed as a side-effect of compilation.
1261 Each time the build system compiles a source file, it computes its
1262 list of dependencies (in C these are the header files included by the
1263 source being compiled). Later, any time @command{make} is run and a
1264 dependency appears to have changed, the dependent files will be
1267 Automake generates code for automatic dependency tracking by default,
1268 unless the developer chooses to override it; for more information,
1269 @pxref{Dependencies}.
1271 When @command{configure} is executed, you can see it probing each
1272 compiler for the dependency mechanism it supports (several mechanisms
1276 ~/amhello-1.0 % @kbd{./configure --prefix /usr}
1278 checking dependency style of gcc... gcc3
1282 Because dependencies are only computed as a side-effect of the
1283 compilation, no dependency information exists the first time a package
1284 is built. This is OK because all the files need to be built anyway:
1285 @code{make} does not have to decide which files need to be rebuilt.
1286 In fact, dependency tracking is completely useless for one-time builds
1287 and there is a @command{configure} option to disable this:
1290 @item --disable-dependency-tracking
1291 @opindex --disable-dependency-tracking
1292 Speed up one-time builds.
1295 Some compilers do not offer any practical way to derive the list of
1296 dependencies as a side-effect of the compilation, requiring a separate
1297 run (maybe of another tool) to compute these dependencies. The
1298 performance penalty implied by these methods is important enough to
1299 disable them by default. The option @option{--enable-dependency-tracking}
1300 must be passed to @command{configure} to activate them.
1303 @item --enable-dependency-tracking
1304 @opindex --enable-dependency-tracking
1305 Do not reject slow dependency extractors.
1308 @xref{Dependency Tracking Evolution}, for some discussion about the
1309 different dependency tracking schemes used by Automake over the years.
1311 @node Nested Packages
1312 @subsection Nested Packages
1313 @cindex Nested packages
1314 @cindex Packages, nested
1317 Although nesting packages isn't something we would recommend to
1318 someone who is discovering the Autotools, it is a nice feature worthy
1319 of mention in this small advertising tour.
1321 Autoconfiscated packages (that means packages whose build system have
1322 been created by Autoconf and friends) can be nested to arbitrary
1325 A typical setup is that package A will distribute one of the libraries
1326 it needs in a subdirectory. This library B is a complete package with
1327 its own GNU Build System. The @command{configure} script of A will
1328 run the @command{configure} script of B as part of its execution,
1329 building and installing A will also build and install B. Generating a
1330 distribution for A will also include B.
1332 It is possible to gather several packages like this. GCC is a heavy
1333 user of this feature. This gives installers a single package to
1334 configure, build and install, while it allows developers to work on
1335 subpackages independently.
1337 When configuring nested packages, the @command{configure} options
1338 given to the top-level @command{configure} are passed recursively to
1339 nested @command{configure}s. A package that does not understand an
1340 option will ignore it, assuming it is meaningful to some other
1343 @opindex --help=recursive
1345 The command @code{configure --help=recursive} can be used to display
1346 the options supported by all the included packages.
1348 @xref{Subpackages}, for an example setup.
1351 @section How Autotools Help
1352 @cindex Autotools, purpose
1354 There are several reasons why you may not want to implement the GNU
1355 Build System yourself (read: write a @file{configure} script and
1356 @file{Makefile}s yourself).
1360 As we have seen, the GNU Build System has a lot of
1361 features (@pxref{Use Cases}).
1362 Some users may expect features you have not implemented because
1363 you did not need them.
1365 Implementing these features portably is difficult and exhausting.
1366 Think of writing portable shell scripts, and portable
1367 @file{Makefile}s, for systems you may not have handy. @xref{Portable
1368 Shell, , Portable Shell Programming, autoconf, The Autoconf Manual}, to
1371 You will have to upgrade your setup to follow changes to the GNU
1375 The GNU Autotools take all this burden off your back and provide:
1379 Tools to create a portable, complete, and self-contained GNU Build
1380 System, from simple instructions.
1381 @emph{Self-contained} meaning the resulting build system does not
1382 require the GNU Autotools.
1384 A central place where fixes and improvements are made:
1385 a bug-fix for a portability issue will benefit every package.
1388 Yet there also exist reasons why you may want NOT to use the
1389 Autotools@enddots{} For instance you may be already using (or used to)
1390 another incompatible build system. Autotools will only be useful if
1391 you do accept the concepts of the GNU Build System. People who have their
1392 own idea of how a build system should work will feel frustrated by the
1396 @section A Small Hello World
1397 @cindex Example Hello World
1398 @cindex Hello World example
1399 @cindex @file{amhello-1.0.tar.gz}, creation
1401 In this section we recreate the @file{amhello-1.0} package from
1402 scratch. The first subsection shows how to call the Autotools to
1403 instantiate the GNU Build System, while the second explains the
1404 meaning of the @file{configure.ac} and @file{Makefile.am} files read
1407 @anchor{amhello Explained}
1409 * Creating amhello:: Create @file{amhello-1.0.tar.gz} from scratch
1410 * amhello's configure.ac Setup Explained::
1411 * amhello's Makefile.am Setup Explained::
1414 @node Creating amhello
1415 @subsection Creating @file{amhello-1.0.tar.gz}
1417 Here is how we can recreate @file{amhello-1.0.tar.gz} from scratch.
1418 The package is simple enough so that we will only need to write 5
1419 files. (You may copy them from the final @file{amhello-1.0.tar.gz}
1420 that is distributed with Automake if you do not want to write them.)
1422 Create the following files in an empty directory.
1427 @file{src/main.c} is the source file for the @file{hello} program. We
1428 store it in the @file{src/} subdirectory, because later, when the package
1429 evolves, it will ease the addition of a @file{man/} directory for man
1430 pages, a @file{data/} directory for data files, etc.
1432 ~/amhello % @kbd{cat src/main.c}
1439 puts ("Hello World!");
1440 puts ("This is " PACKAGE_STRING ".");
1446 @file{README} contains some very limited documentation for our little
1449 ~/amhello % @kbd{cat README}
1450 This is a demonstration package for GNU Automake.
1451 Type `info Automake' to read the Automake manual.
1455 @file{Makefile.am} and @file{src/Makefile.am} contain Automake
1456 instructions for these two directories.
1459 ~/amhello % @kbd{cat src/Makefile.am}
1460 bin_PROGRAMS = hello
1461 hello_SOURCES = main.c
1462 ~/amhello % @kbd{cat Makefile.am}
1464 dist_doc_DATA = README
1468 Finally, @file{configure.ac} contains Autoconf instructions to
1469 create the @command{configure} script.
1472 ~/amhello % @kbd{cat configure.ac}
1473 AC_INIT([amhello], [1.0], [@value{PACKAGE_BUGREPORT}])
1474 AM_INIT_AUTOMAKE([-Wall -Werror foreign])
1476 AC_CONFIG_HEADERS([config.h])
1485 @cindex @command{autoreconf}, example
1487 Once you have these five files, it is time to run the Autotools to
1488 instantiate the build system. Do this using the @command{autoreconf}
1492 ~/amhello % @kbd{autoreconf --install}
1493 configure.ac: installing `./install-sh'
1494 configure.ac: installing `./missing'
1495 src/Makefile.am: installing `./depcomp'
1498 At this point the build system is complete.
1500 In addition to the three scripts mentioned in its output, you can see
1501 that @command{autoreconf} created four other files: @file{configure},
1502 @file{config.h.in}, @file{Makefile.in}, and @file{src/Makefile.in}.
1503 The latter three files are templates that will be adapted to the
1504 system by @command{configure} under the names @file{config.h},
1505 @file{Makefile}, and @file{src/Makefile}. Let's do this:
1508 ~/amhello % @kbd{./configure}
1509 checking for a BSD-compatible install... /usr/bin/install -c
1510 checking whether build environment is sane... yes
1511 checking for gawk... no
1512 checking for mawk... mawk
1513 checking whether make sets $(MAKE)... yes
1514 checking for gcc... gcc
1515 checking for C compiler default output file name... a.out
1516 checking whether the C compiler works... yes
1517 checking whether we are cross compiling... no
1518 checking for suffix of executables...
1519 checking for suffix of object files... o
1520 checking whether we are using the GNU C compiler... yes
1521 checking whether gcc accepts -g... yes
1522 checking for gcc option to accept ISO C89... none needed
1523 checking for style of include used by make... GNU
1524 checking dependency style of gcc... gcc3
1525 configure: creating ./config.status
1526 config.status: creating Makefile
1527 config.status: creating src/Makefile
1528 config.status: creating config.h
1529 config.status: executing depfiles commands
1533 @cindex @code{distcheck} example
1535 You can see @file{Makefile}, @file{src/Makefile}, and @file{config.h}
1536 being created at the end after @command{configure} has probed the
1537 system. It is now possible to run all the targets we wish
1538 (@pxref{Standard Targets}). For instance:
1541 ~/amhello % @kbd{make}
1543 ~/amhello % @kbd{src/hello}
1545 This is amhello 1.0.
1546 ~/amhello % @kbd{make distcheck}
1548 =============================================
1549 amhello-1.0 archives ready for distribution:
1551 =============================================
1554 Note that running @command{autoreconf} is only needed initially when
1555 the GNU Build System does not exist. When you later change some
1556 instructions in a @file{Makefile.am} or @file{configure.ac}, the
1557 relevant part of the build system will be regenerated automatically
1558 when you execute @command{make}.
1560 @command{autoreconf} is a script that calls @command{autoconf},
1561 @command{automake}, and a bunch of other commands in the right order.
1562 If you are beginning with these tools, it is not important to figure
1563 out in which order all these tools should be invoked and why. However,
1564 because Autoconf and Automake have separate manuals, the important
1565 point to understand is that @command{autoconf} is in charge of
1566 creating @file{configure} from @file{configure.ac}, while
1567 @command{automake} is in charge of creating @file{Makefile.in}s from
1568 @file{Makefile.am}s and @file{configure.ac}. This should at least
1569 direct you to the right manual when seeking answers.
1572 @node amhello's configure.ac Setup Explained
1573 @subsection @code{amhello}'s @file{configure.ac} Setup Explained
1575 @cindex @file{configure.ac}, Hello World
1577 Let us begin with the contents of @file{configure.ac}.
1580 AC_INIT([amhello], [1.0], [@value{PACKAGE_BUGREPORT}])
1581 AM_INIT_AUTOMAKE([-Wall -Werror foreign])
1583 AC_CONFIG_HEADERS([config.h])
1591 This file is read by both @command{autoconf} (to create
1592 @file{configure}) and @command{automake} (to create the various
1593 @file{Makefile.in}s). It contains a series of M4 macros that will be
1594 expanded as shell code to finally form the @file{configure} script.
1595 We will not elaborate on the syntax of this file, because the Autoconf
1596 manual has a whole section about it (@pxref{Writing Autoconf Input, ,
1597 Writing @file{configure.ac}, autoconf, The Autoconf Manual}).
1599 The macros prefixed with @code{AC_} are Autoconf macros, documented
1600 in the Autoconf manual (@pxref{Autoconf Macro Index, , Autoconf Macro
1601 Index, autoconf, The Autoconf Manual}). The macros that start with
1602 @code{AM_} are Automake macros, documented later in this manual
1603 (@pxref{Macro Index}).
1605 The first two lines of @file{configure.ac} initialize Autoconf and
1606 Automake. @code{AC_INIT} takes in as parameters the name of the package,
1607 its version number, and a contact address for bug-reports about the
1608 package (this address is output at the end of @code{./configure
1609 --help}, for instance). When adapting this setup to your own package,
1610 by all means please do not blindly copy Automake's address: use the
1611 mailing list of your package, or your own mail address.
1617 The argument to @code{AM_INIT_AUTOMAKE} is a list of options for
1618 @command{automake} (@pxref{Options}). @option{-Wall} and
1619 @option{-Werror} ask @command{automake} to turn on all warnings and
1620 report them as errors. We are speaking of @strong{Automake} warnings
1621 here, such as dubious instructions in @file{Makefile.am}. This has
1622 absolutely nothing to do with how the compiler will be called, even
1623 though it may support options with similar names. Using @option{-Wall
1624 -Werror} is a safe setting when starting to work on a package: you do
1625 not want to miss any issues. Later you may decide to relax things a
1626 bit. The @option{foreign} option tells Automake that this package
1627 will not follow the GNU Standards. GNU packages should always
1628 distribute additional files such as @file{ChangeLog}, @file{AUTHORS},
1629 etc. We do not want @command{automake} to complain about these
1630 missing files in our small example.
1632 The @code{AC_PROG_CC} line causes the @command{configure} script to
1633 search for a C compiler and define the variable @code{CC} with its
1634 name. The @file{src/Makefile.in} file generated by Automake uses the
1635 variable @code{CC} to build @file{hello}, so when @command{configure}
1636 creates @file{src/Makefile} from @file{src/Makefile.in}, it will define
1637 @code{CC} with the value it has found. If Automake is asked to create
1638 a @file{Makefile.in} that uses @code{CC} but @file{configure.ac} does
1639 not define it, it will suggest you add a call to @code{AC_PROG_CC}.
1641 The @code{AC_CONFIG_HEADERS([config.h])} invocation causes the
1642 @command{configure} script to create a @file{config.h} file gathering
1643 @samp{#define}s defined by other macros in @file{configure.ac}. In our
1644 case, the @code{AC_INIT} macro already defined a few of them. Here
1645 is an excerpt of @file{config.h} after @command{configure} has run:
1649 /* Define to the address where bug reports for this package should be sent. */
1650 #define PACKAGE_BUGREPORT "@value{PACKAGE_BUGREPORT}"
1652 /* Define to the full name and version of this package. */
1653 #define PACKAGE_STRING "amhello 1.0"
1657 As you probably noticed, @file{src/main.c} includes @file{config.h} so
1658 it can use @code{PACKAGE_STRING}. In a real-world project,
1659 @file{config.h} can grow really big, with one @samp{#define} per
1660 feature probed on the system.
1662 The @code{AC_CONFIG_FILES} macro declares the list of files that
1663 @command{configure} should create from their @file{*.in} templates.
1664 Automake also scans this list to find the @file{Makefile.am} files it must
1665 process. (This is important to remember: when adding a new directory
1666 to your project, you should add its @file{Makefile} to this list,
1667 otherwise Automake will never process the new @file{Makefile.am} you
1668 wrote in that directory.)
1670 Finally, the @code{AC_OUTPUT} line is a closing command that actually
1671 produces the part of the script in charge of creating the files
1672 registered with @code{AC_CONFIG_HEADERS} and @code{AC_CONFIG_FILES}.
1674 @cindex @command{autoscan}
1676 When starting a new project, we suggest you start with such a simple
1677 @file{configure.ac}, and gradually add the other tests it requires.
1678 The command @command{autoscan} can also suggest a few of the tests
1679 your package may need (@pxref{autoscan Invocation, , Using
1680 @command{autoscan} to Create @file{configure.ac}, autoconf, The
1684 @node amhello's Makefile.am Setup Explained
1685 @subsection @code{amhello}'s @file{Makefile.am} Setup Explained
1687 @cindex @file{Makefile.am}, Hello World
1689 We now turn to @file{src/Makefile.am}. This file contains
1690 Automake instructions to build and install @file{hello}.
1693 bin_PROGRAMS = hello
1694 hello_SOURCES = main.c
1697 A @file{Makefile.am} has the same syntax as an ordinary
1698 @file{Makefile}. When @command{automake} processes a
1699 @file{Makefile.am} it copies the entire file into the output
1700 @file{Makefile.in} (that will be later turned into @file{Makefile} by
1701 @command{configure}) but will react to certain variable definitions
1702 by generating some build rules and other variables.
1703 Often @file{Makefile.am}s contain only a list of variable definitions as
1704 above, but they can also contain other variable and rule definitions that
1705 @command{automake} will pass along without interpretation.
1707 Variables that end with @code{_PROGRAMS} are special variables
1708 that list programs that the resulting @file{Makefile} should build.
1709 In Automake speak, this @code{_PROGRAMS} suffix is called a
1710 @dfn{primary}; Automake recognizes other primaries such as
1711 @code{_SCRIPTS}, @code{_DATA}, @code{_LIBRARIES}, etc.@: corresponding
1712 to different types of files.
1714 The @samp{bin} part of the @code{bin_PROGRAMS} tells
1715 @command{automake} that the resulting programs should be installed in
1716 @var{bindir}. Recall that the GNU Build System uses a set of variables
1717 to denote destination directories and allow users to customize these
1718 locations (@pxref{Standard Directory Variables}). Any such directory
1719 variable can be put in front of a primary (omitting the @code{dir}
1720 suffix) to tell @command{automake} where to install the listed files.
1722 Programs need to be built from source files, so for each program
1723 @code{@var{prog}} listed in a @code{@w{_PROGRAMS}} variable,
1724 @command{automake} will look for another variable named
1725 @code{@var{prog}_SOURCES} listing its source files. There may be more
1726 than one source file: they will all be compiled and linked together.
1728 Automake also knows that source files need to be distributed when
1729 creating a tarball (unlike built programs). So a side-effect of this
1730 @code{hello_SOURCES} declaration is that @file{main.c} will be
1731 part of the tarball created by @code{make dist}.
1733 Finally here are some explanations regarding the top-level
1738 dist_doc_DATA = README
1741 @code{SUBDIRS} is a special variable listing all directories that
1742 @command{make} should recurse into before processing the current
1743 directory. So this line is responsible for @command{make} building
1744 @file{src/hello} even though we run it from the top-level. This line
1745 also causes @code{make install} to install @file{src/hello} before
1746 installing @file{README} (not that this order matters).
1748 The line @code{dist_doc_DATA = README} causes @file{README} to be
1749 distributed and installed in @var{docdir}. Files listed with the
1750 @code{_DATA} primary are not automatically part of the tarball built
1751 with @code{make dist}, so we add the @code{dist_} prefix so they get
1752 distributed. However, for @file{README} it would not have been
1753 necessary: @command{automake} automatically distributes any
1754 @file{README} file it encounters (the list of other files
1755 automatically distributed is presented by @code{automake --help}).
1756 The only important effect of this second line is therefore to install
1757 @file{README} during @code{make install}.
1759 One thing not covered in this example is accessing the installation
1760 directory values (@pxref{Standard Directory Variables}) from your
1761 program code, that is, converting them into defined macros. For this,
1762 @pxref{Defining Directories,,, autoconf, The Autoconf Manual}.
1766 @chapter General ideas
1768 The following sections cover a few basic ideas that will help you
1769 understand how Automake works.
1772 * General Operation:: General operation of Automake
1773 * Strictness:: Standards conformance checking
1774 * Uniform:: The Uniform Naming Scheme
1775 * Length Limitations:: Staying below the command line length limit
1776 * Canonicalization:: How derived variables are named
1777 * User Variables:: Variables reserved for the user
1778 * Auxiliary Programs:: Programs automake might require
1782 @node General Operation
1783 @section General Operation
1785 Automake works by reading a @file{Makefile.am} and generating a
1786 @file{Makefile.in}. Certain variables and rules defined in the
1787 @file{Makefile.am} instruct Automake to generate more specialized code;
1788 for instance, a @code{bin_PROGRAMS} variable definition will cause rules
1789 for compiling and linking programs to be generated.
1791 @cindex Non-standard targets
1792 @cindex @code{git-dist}, non-standard example
1795 The variable definitions and rules in the @file{Makefile.am} are
1796 copied mostly verbatim into the generated file, with all variable
1797 definitions preceding all rules. This allows you to add almost
1798 arbitrary code into the generated @file{Makefile.in}. For instance,
1799 the Automake distribution includes a non-standard rule for the
1800 @code{git-dist} target, which the Automake maintainer uses to make
1801 distributions from the source control system.
1803 @cindex GNU make extensions
1805 Note that most GNU make extensions are not recognized by Automake. Using
1806 such extensions in a @file{Makefile.am} will lead to errors or confusing
1809 @cindex Append operator
1811 A special exception is that the GNU make append operator, @samp{+=}, is
1812 supported. This operator appends its right hand argument to the variable
1813 specified on the left. Automake will translate the operator into
1814 an ordinary @samp{=} operator; @samp{+=} will thus work with any make program.
1816 Automake tries to keep comments grouped with any adjoining rules or
1817 variable definitions.
1819 @cindex Limitations of automake parser
1820 @cindex Automake parser, limitations of
1821 @cindex indentation in Makefile.am
1822 Generally, Automake is not particularly smart in the parsing of unusual
1823 Makefile constructs, so you're advised to avoid fancy constructs or
1824 ``creative'' use of whitespaces.
1825 @c Keep this in sync with doc-parsing-buglets-tabs.test.
1826 For example, @key{TAB} characters cannot be used between a target name
1827 and the following ``@code{:}'' character, and variable assignments
1828 shouldn't be indented with @key{TAB} characters.
1829 @c Keep this in sync with doc-parsing-buglets-colneq-subst.test.
1830 Also, using more complex macro in target names can cause trouble:
1833 % @kbd{cat Makefile.am}
1836 Makefile.am:1: bad characters in variable name `$(FOO'
1837 Makefile.am:1: `:='-style assignments are not portable
1840 @cindex Make targets, overriding
1841 @cindex Make rules, overriding
1842 @cindex Overriding make rules
1843 @cindex Overriding make targets
1845 A rule defined in @file{Makefile.am} generally overrides any such
1846 rule of a similar name that would be automatically generated by
1847 @command{automake}. Although this is a supported feature, it is generally
1848 best to avoid making use of it, as sometimes the generated rules are
1851 @cindex Variables, overriding
1852 @cindex Overriding make variables
1854 Similarly, a variable defined in @file{Makefile.am} or
1855 @code{AC_SUBST}ed from @file{configure.ac} will override any
1856 definition of the variable that @command{automake} would ordinarily
1857 create. This feature is more often useful than the ability to
1858 override a rule. Be warned that many of the variables generated by
1859 @command{automake} are considered to be for internal use only, and their
1860 names might change in future releases.
1862 @cindex Recursive operation of Automake
1863 @cindex Automake, recursive operation
1864 @cindex Example of recursive operation
1866 When examining a variable definition, Automake will recursively examine
1867 variables referenced in the definition. For example, if Automake is
1868 looking at the content of @code{foo_SOURCES} in this snippet
1870 @c Keep in sync with interp.test.
1873 foo_SOURCES = c.c $(xs)
1876 it would use the files @file{a.c}, @file{b.c}, and @file{c.c} as the
1877 contents of @code{foo_SOURCES}.
1879 @cindex @code{##} (special Automake comment)
1880 @cindex Special Automake comment
1881 @cindex Comment, special to Automake
1883 Automake also allows a form of comment that is @emph{not} copied into
1884 the output; all lines beginning with @samp{##} (leading spaces allowed)
1885 are completely ignored by Automake.
1887 It is customary to make the first line of @file{Makefile.am} read:
1889 @cindex Makefile.am, first line
1890 @cindex First line of Makefile.am
1893 ## Process this file with automake to produce Makefile.in
1896 @c FIXME discuss putting a copyright into Makefile.am here? I would but
1897 @c I don't know quite what to say.
1899 @c FIXME document customary ordering of Makefile.am here!
1905 @cindex Non-GNU packages
1907 While Automake is intended to be used by maintainers of GNU packages, it
1908 does make some effort to accommodate those who wish to use it, but do
1909 not want to use all the GNU conventions.
1911 @cindex Strictness, defined
1912 @cindex Strictness, @option{foreign}
1913 @cindex @option{foreign} strictness
1914 @cindex Strictness, @option{gnu}
1915 @cindex @option{gnu} strictness
1916 @cindex Strictness, @option{gnits}
1917 @cindex @option{gnits} strictness
1919 To this end, Automake supports three levels of @dfn{strictness}---the
1920 strictness indicating how stringently Automake should check standards
1923 The valid strictness levels are:
1927 Automake will check for only those things that are absolutely
1928 required for proper operations. For instance, whereas GNU standards
1929 dictate the existence of a @file{NEWS} file, it will not be required in
1930 this mode. The name comes from the fact that Automake is intended to be
1931 used for GNU programs; these relaxed rules are not the standard mode of
1935 Automake will check---as much as possible---for compliance to the GNU
1936 standards for packages. This is the default.
1939 Automake will check for compliance to the as-yet-unwritten @dfn{Gnits
1940 standards}. These are based on the GNU standards, but are even more
1941 detailed. Unless you are a Gnits standards contributor, it is
1942 recommended that you avoid this option until such time as the Gnits
1943 standard is actually published (which may never happen).
1946 @xref{Gnits}, for more information on the precise implications of the
1949 Automake also has a special ``cygnus'' mode that is similar to
1950 strictness but handled differently. This mode is useful for packages
1951 that are put into a ``Cygnus'' style tree (e.g., the GCC tree).
1952 @xref{Cygnus}, for more information on this mode.
1956 @section The Uniform Naming Scheme
1958 @cindex Uniform naming scheme
1960 Automake variables generally follow a @dfn{uniform naming scheme} that
1961 makes it easy to decide how programs (and other derived objects) are
1962 built, and how they are installed. This scheme also supports
1963 @command{configure} time determination of what should be built.
1965 @cindex @code{_PROGRAMS} primary variable
1966 @cindex @code{PROGRAMS} primary variable
1967 @cindex Primary variable, @code{PROGRAMS}
1968 @cindex Primary variable, defined
1971 At @command{make} time, certain variables are used to determine which
1972 objects are to be built. The variable names are made of several pieces
1973 that are concatenated together.
1975 The piece that tells @command{automake} what is being built is commonly called
1976 the @dfn{primary}. For instance, the primary @code{PROGRAMS} holds a
1977 list of programs that are to be compiled and linked.
1980 @cindex @code{pkgdatadir}, defined
1981 @cindex @code{pkgincludedir}, defined
1982 @cindex @code{pkglibdir}, defined
1983 @cindex @code{pkglibexecdir}, defined
1986 @vindex pkgincludedir
1988 @vindex pkglibexecdir
1990 @cindex @code{PACKAGE}, directory
1991 A different set of names is used to decide where the built objects
1992 should be installed. These names are prefixes to the primary, and they
1993 indicate which standard directory should be used as the installation
1994 directory. The standard directory names are given in the GNU standards
1995 (@pxref{Directory Variables, , , standards, The GNU Coding Standards}).
1996 Automake extends this list with @code{pkgdatadir}, @code{pkgincludedir},
1997 @code{pkglibdir}, and @code{pkglibexecdir}; these are the same as the
1998 non-@samp{pkg} versions, but with @samp{$(PACKAGE)} appended. For instance,
1999 @code{pkglibdir} is defined as @samp{$(libdir)/$(PACKAGE)}.
2001 @cindex @code{EXTRA_}, prepending
2002 For each primary, there is one additional variable named by prepending
2003 @samp{EXTRA_} to the primary name. This variable is used to list
2004 objects that may or may not be built, depending on what
2005 @command{configure} decides. This variable is required because Automake
2006 must statically know the entire list of objects that may be built in
2007 order to generate a @file{Makefile.in} that will work in all cases.
2009 @cindex @code{EXTRA_PROGRAMS}, defined
2010 @cindex Example, @code{EXTRA_PROGRAMS}
2011 @cindex @command{cpio} example
2013 For instance, @command{cpio} decides at configure time which programs
2014 should be built. Some of the programs are installed in @code{bindir},
2015 and some are installed in @code{sbindir}:
2018 EXTRA_PROGRAMS = mt rmt
2019 bin_PROGRAMS = cpio pax
2020 sbin_PROGRAMS = $(MORE_PROGRAMS)
2023 Defining a primary without a prefix as a variable, e.g.,
2024 @samp{PROGRAMS}, is an error.
2026 Note that the common @samp{dir} suffix is left off when constructing the
2027 variable names; thus one writes @samp{bin_PROGRAMS} and not
2028 @samp{bindir_PROGRAMS}.
2030 Not every sort of object can be installed in every directory. Automake
2031 will flag those attempts it finds in error (but see below how to override
2032 the check if you really need to).
2033 Automake will also diagnose obvious misspellings in directory names.
2035 @cindex Extending list of installation directories
2036 @cindex Installation directories, extending list
2038 Sometimes the standard directories---even as augmented by
2039 Automake---are not enough. In particular it is sometimes useful, for
2040 clarity, to install objects in a subdirectory of some predefined
2041 directory. To this end, Automake allows you to extend the list of
2042 possible installation directories. A given prefix (e.g., @samp{zar})
2043 is valid if a variable of the same name with @samp{dir} appended is
2044 defined (e.g., @samp{zardir}).
2046 For instance, the following snippet will install @file{file.xml} into
2047 @samp{$(datadir)/xml}.
2049 @c Keep in sync with primary-prefix-couples-documented-valid.test.
2051 xmldir = $(datadir)/xml
2055 This feature can also be used to override the sanity checks Automake
2056 performs to diagnose suspicious directory/primary couples (in the
2057 unlikely case these checks are undesirable, and you really know what
2058 you're doing). For example, Automake would error out on this input:
2060 @c Should be tested in primary-prefix-invalid-couples.test.
2062 # Forbidden directory combinations, automake will error out on this.
2063 pkglib_PROGRAMS = foo
2064 doc_LIBRARIES = libquux.a
2068 but it will succeed with this:
2070 @c Keep in sync with primary-prefix-couples-documented-valid.test.
2072 # Work around forbidden directory combinations. Do not use this
2073 # without a very good reason!
2074 my_execbindir = $(pkglibdir)
2075 my_doclibdir = $(docdir)
2076 my_execbin_PROGRAMS = foo
2077 my_doclib_LIBRARIES = libquux.a
2080 The @samp{exec} substring of the @samp{my_execbindir} variable lets
2081 the files be installed at the right time (@pxref{The Two Parts of
2084 @cindex @samp{noinst_} primary prefix, definition
2087 The special prefix @samp{noinst_} indicates that the objects in question
2088 should be built but not installed at all. This is usually used for
2089 objects required to build the rest of your package, for instance static
2090 libraries (@pxref{A Library}), or helper scripts.
2092 @cindex @samp{check_} primary prefix, definition
2095 The special prefix @samp{check_} indicates that the objects in question
2096 should not be built until the @samp{make check} command is run. Those
2097 objects are not installed either.
2099 The current primary names are @samp{PROGRAMS}, @samp{LIBRARIES},
2100 @samp{LTLIBRARIES}, @samp{LISP}, @samp{PYTHON}, @samp{JAVA},
2101 @samp{SCRIPTS}, @samp{DATA}, @samp{HEADERS}, @samp{MANS}, and
2115 Some primaries also allow additional prefixes that control other
2116 aspects of @command{automake}'s behavior. The currently defined prefixes
2117 are @samp{dist_}, @samp{nodist_}, @samp{nobase_}, and @samp{notrans_}.
2118 These prefixes are explained later (@pxref{Program and Library Variables})
2119 (@pxref{Man Pages}).
2122 @node Length Limitations
2123 @section Staying below the command line length limit
2125 @cindex command line length limit
2128 Traditionally, most unix-like systems have a length limitation for the
2129 command line arguments and environment contents when creating new
2130 processes (see for example
2131 @uref{http://www.in-ulm.de/@/~mascheck/@/various/@/argmax/} for an
2132 overview on this issue),
2133 which of course also applies to commands spawned by @command{make}.
2134 POSIX requires this limit to be at least 4096 bytes, and most modern
2135 systems have quite high limits (or are unlimited).
2137 In order to create portable Makefiles that do not trip over these
2138 limits, it is necessary to keep the length of file lists bounded.
2139 Unfortunately, it is not possible to do so fully transparently within
2140 Automake, so your help may be needed. Typically, you can split long
2141 file lists manually and use different installation directory names for
2142 each list. For example,
2145 data_DATA = file1 @dots{} file@var{N} file@var{N+1} @dots{} file@var{2N}
2149 may also be written as
2151 @c Keep in sync with primary-prefix-couples-documented-valid.test.
2153 data_DATA = file1 @dots{} file@var{N}
2154 data2dir = $(datadir)
2155 data2_DATA = file@var{N+1} @dots{} file@var{2N}
2159 and will cause Automake to treat the two lists separately during
2160 @code{make install}. See @ref{The Two Parts of Install} for choosing
2161 directory names that will keep the ordering of the two parts of
2162 installation Note that @code{make dist} may still only work on a host
2163 with a higher length limit in this example.
2165 Automake itself employs a couple of strategies to avoid long command
2166 lines. For example, when @samp{$@{srcdir@}/} is prepended to file
2167 names, as can happen with above @code{$(data_DATA)} lists, it limits
2168 the amount of arguments passed to external commands.
2170 Unfortunately, some system's @command{make} commands may prepend
2171 @code{VPATH} prefixes like @samp{$@{srcdir@}/} to file names from the
2172 source tree automatically (@pxref{Automatic Rule Rewriting, , Automatic
2173 Rule Rewriting, autoconf, The Autoconf Manual}). In this case, the user
2174 may have to switch to use GNU Make, or refrain from using VPATH builds,
2175 in order to stay below the length limit.
2177 For libraries and programs built from many sources, convenience archives
2178 may be used as intermediates in order to limit the object list length
2179 (@pxref{Libtool Convenience Libraries}).
2182 @node Canonicalization
2183 @section How derived variables are named
2185 @cindex canonicalizing Automake variables
2187 Sometimes a Makefile variable name is derived from some text the
2188 maintainer supplies. For instance, a program name listed in
2189 @samp{_PROGRAMS} is rewritten into the name of a @samp{_SOURCES}
2190 variable. In cases like this, Automake canonicalizes the text, so that
2191 program names and the like do not have to follow Makefile variable naming
2192 rules. All characters in the name except for letters, numbers, the
2193 strudel (@@), and the underscore are turned into underscores when making
2194 variable references.
2196 For example, if your program is named @file{sniff-glue}, the derived
2197 variable name would be @samp{sniff_glue_SOURCES}, not
2198 @samp{sniff-glue_SOURCES}. Similarly the sources for a library named
2199 @file{libmumble++.a} should be listed in the
2200 @samp{libmumble___a_SOURCES} variable.
2202 The strudel is an addition, to make the use of Autoconf substitutions in
2203 variable names less obfuscating.
2206 @node User Variables
2207 @section Variables reserved for the user
2209 @cindex variables, reserved for the user
2210 @cindex user variables
2212 Some @file{Makefile} variables are reserved by the GNU Coding Standards
2213 for the use of the ``user''---the person building the package. For
2214 instance, @code{CFLAGS} is one such variable.
2216 Sometimes package developers are tempted to set user variables such as
2217 @code{CFLAGS} because it appears to make their job easier. However,
2218 the package itself should never set a user variable, particularly not
2219 to include switches that are required for proper compilation of the
2220 package. Since these variables are documented as being for the
2221 package builder, that person rightfully expects to be able to override
2222 any of these variables at build time.
2224 To get around this problem, Automake introduces an automake-specific
2225 shadow variable for each user flag variable. (Shadow variables are
2226 not introduced for variables like @code{CC}, where they would make no
2227 sense.) The shadow variable is named by prepending @samp{AM_} to the
2228 user variable's name. For instance, the shadow variable for
2229 @code{YFLAGS} is @code{AM_YFLAGS}. The package maintainer---that is,
2230 the author(s) of the @file{Makefile.am} and @file{configure.ac}
2231 files---may adjust these shadow variables however necessary.
2233 @xref{Flag Variables Ordering}, for more discussion about these
2234 variables and how they interact with per-target variables.
2236 @node Auxiliary Programs
2237 @section Programs automake might require
2239 @cindex Programs, auxiliary
2240 @cindex Auxiliary programs
2242 Automake sometimes requires helper programs so that the generated
2243 @file{Makefile} can do its work properly. There are a fairly large
2244 number of them, and we list them here.
2246 Although all of these files are distributed and installed with
2247 Automake, a couple of them are maintained separately. The Automake
2248 copies are updated before each release, but we mention the original
2249 source in case you need more recent versions.
2253 This is a wrapper primarily for the Microsoft lib archiver, to make
2258 These two files are used for de-ANSI-fication support (they are
2259 deprecated now, and @emph{will be removed} in the next major Automake
2260 release; @pxref{ANSI}).
2263 This is a wrapper for compilers that do not accept options @option{-c}
2264 and @option{-o} at the same time. It is only used when absolutely
2265 required. Such compilers are rare, with the Microsoft C/C++ Compiler
2266 as the most notable exception. This wrapper also makes the following
2267 common options available for that compiler, while performing file name
2268 translation where needed: @option{-I}, @option{-L}, @option{-l},
2269 @option{-Wl,} and @option{-Xlinker}.
2273 These two programs compute the canonical triplets for the given build,
2274 host, or target architecture. These programs are updated regularly to
2275 support new architectures and fix probes broken by changes in new
2276 kernel versions. Each new release of Automake comes with up-to-date
2277 copies of these programs. If your copy of Automake is getting old,
2278 you are encouraged to fetch the latest versions of these files from
2279 @url{http://savannah.gnu.org/git/?group=config} before making a
2283 This file is not a program, it is a @file{configure} fragment used for
2284 multilib support (@pxref{Multilibs}). This file is maintained in the
2285 GCC tree at @url{http://gcc.gnu.org/svn.html}.
2288 This program understands how to run a compiler so that it will
2289 generate not only the desired output but also dependency information
2290 that is then used by the automatic dependency tracking feature
2291 (@pxref{Dependencies}).
2294 This program is used to byte-compile Emacs Lisp code.
2297 This is a replacement for the @command{install} program that works on
2298 platforms where @command{install} is unavailable or unusable.
2301 This script is used to generate a @file{version.texi} file. It examines
2302 a file and prints some date information about it.
2305 This wraps a number of programs that are typically only required by
2306 maintainers. If the program in question doesn't exist,
2307 @command{missing} prints an informative warning and attempts to fix
2308 things so that the build can continue.
2311 This script used to be a wrapper around @samp{mkdir -p}, which is not
2312 portable. Now we prefer to use @samp{install-sh -d} when @command{configure}
2313 finds that @samp{mkdir -p} does not work, this makes one less script to
2316 For backward compatibility @file{mkinstalldirs} is still used and
2317 distributed when @command{automake} finds it in a package. But it is no
2318 longer installed automatically, and it should be safe to remove it.
2321 This is used to byte-compile Python scripts.
2324 This program duplicates a tree of directories, using symbolic links
2325 instead of copying files. Such an operation is performed when building
2326 multilibs (@pxref{Multilibs}). This file is maintained in the GCC
2327 tree at @url{http://gcc.gnu.org/svn.html}.
2330 Not a program, this file is required for @samp{make dvi}, @samp{make
2331 ps} and @samp{make pdf} to work when Texinfo sources are in the
2332 package. The latest version can be downloaded from
2333 @url{http://www.gnu.org/software/texinfo/}.
2336 This program wraps @command{lex} and @command{yacc} to rename their
2337 output files. It also ensures that, for instance, multiple
2338 @command{yacc} instances can be invoked in a single directory in
2345 @chapter Some example packages
2347 This section contains two small examples.
2349 The first example (@pxref{Complete}) assumes you have an existing
2350 project already using Autoconf, with handcrafted @file{Makefile}s, and
2351 that you want to convert it to using Automake. If you are discovering
2352 both tools, it is probably better that you look at the Hello World
2353 example presented earlier (@pxref{Hello World}).
2355 The second example (@pxref{true}) shows how two programs can be built
2356 from the same file, using different compilation parameters. It
2357 contains some technical digressions that are probably best skipped on
2361 * Complete:: A simple example, start to finish
2362 * true:: Building true and false
2367 @section A simple example, start to finish
2369 @cindex Complete example
2371 Let's suppose you just finished writing @code{zardoz}, a program to make
2372 your head float from vortex to vortex. You've been using Autoconf to
2373 provide a portability framework, but your @file{Makefile.in}s have been
2374 ad-hoc. You want to make them bulletproof, so you turn to Automake.
2376 @cindex @code{AM_INIT_AUTOMAKE}, example use
2378 The first step is to update your @file{configure.ac} to include the
2379 commands that @command{automake} needs. The way to do this is to add an
2380 @code{AM_INIT_AUTOMAKE} call just after @code{AC_INIT}:
2383 AC_INIT([zardoz], [1.0])
2388 Since your program doesn't have any complicating factors (e.g., it
2389 doesn't use @code{gettext}, it doesn't want to build a shared library),
2390 you're done with this part. That was easy!
2392 @cindex @command{aclocal} program, introduction
2393 @cindex @file{aclocal.m4}, preexisting
2394 @cindex @file{acinclude.m4}, defined
2396 Now you must regenerate @file{configure}. But to do that, you'll need
2397 to tell @command{autoconf} how to find the new macro you've used. The
2398 easiest way to do this is to use the @command{aclocal} program to
2399 generate your @file{aclocal.m4} for you. But wait@dots{} maybe you
2400 already have an @file{aclocal.m4}, because you had to write some hairy
2401 macros for your program. The @command{aclocal} program lets you put
2402 your own macros into @file{acinclude.m4}, so simply rename and then
2406 mv aclocal.m4 acinclude.m4
2411 @cindex @command{zardoz} example
2413 Now it is time to write your @file{Makefile.am} for @code{zardoz}.
2414 Since @code{zardoz} is a user program, you want to install it where the
2415 rest of the user programs go: @code{bindir}. Additionally,
2416 @code{zardoz} has some Texinfo documentation. Your @file{configure.ac}
2417 script uses @code{AC_REPLACE_FUNCS}, so you need to link against
2418 @samp{$(LIBOBJS)}. So here's what you'd write:
2421 bin_PROGRAMS = zardoz
2422 zardoz_SOURCES = main.c head.c float.c vortex9.c gun.c
2423 zardoz_LDADD = $(LIBOBJS)
2425 info_TEXINFOS = zardoz.texi
2428 Now you can run @samp{automake --add-missing} to generate your
2429 @file{Makefile.in} and grab any auxiliary files you might need, and
2434 @section Building true and false
2436 @cindex Example, @command{false} and @command{true}
2437 @cindex @command{false} Example
2438 @cindex @command{true} Example
2440 Here is another, trickier example. It shows how to generate two
2441 programs (@code{true} and @code{false}) from the same source file
2442 (@file{true.c}). The difficult part is that each compilation of
2443 @file{true.c} requires different @code{cpp} flags.
2446 bin_PROGRAMS = true false
2448 false_LDADD = false.o
2451 $(COMPILE) -DEXIT_CODE=0 -c true.c
2454 $(COMPILE) -DEXIT_CODE=1 -o false.o -c true.c
2457 Note that there is no @code{true_SOURCES} definition. Automake will
2458 implicitly assume that there is a source file named @file{true.c}
2459 (@pxref{Default _SOURCES}), and
2460 define rules to compile @file{true.o} and link @file{true}. The
2461 @samp{true.o: true.c} rule supplied by the above @file{Makefile.am},
2462 will override the Automake generated rule to build @file{true.o}.
2464 @code{false_SOURCES} is defined to be empty---that way no implicit value
2465 is substituted. Because we have not listed the source of
2466 @file{false}, we have to tell Automake how to link the program. This is
2467 the purpose of the @code{false_LDADD} line. A @code{false_DEPENDENCIES}
2468 variable, holding the dependencies of the @file{false} target will be
2469 automatically generated by Automake from the content of
2472 The above rules won't work if your compiler doesn't accept both
2473 @option{-c} and @option{-o}. The simplest fix for this is to introduce a
2474 bogus dependency (to avoid problems with a parallel @command{make}):
2477 true.o: true.c false.o
2478 $(COMPILE) -DEXIT_CODE=0 -c true.c
2481 $(COMPILE) -DEXIT_CODE=1 -c true.c && mv true.o false.o
2484 As it turns out, there is also a much easier way to do this same task.
2485 Some of the above technique is useful enough that we've kept the
2486 example in the manual. However if you were to build @code{true} and
2487 @code{false} in real life, you would probably use per-program
2488 compilation flags, like so:
2490 @c Keep in sync with specflg7.test and specflg8.test.
2492 bin_PROGRAMS = false true
2494 false_SOURCES = true.c
2495 false_CPPFLAGS = -DEXIT_CODE=1
2497 true_SOURCES = true.c
2498 true_CPPFLAGS = -DEXIT_CODE=0
2501 In this case Automake will cause @file{true.c} to be compiled twice,
2502 with different flags. In this instance, the names of the object files
2503 would be chosen by automake; they would be @file{false-true.o} and
2504 @file{true-true.o}. (The name of the object files rarely matters.)
2507 @node Invoking Automake
2508 @chapter Creating a @file{Makefile.in}
2510 @cindex Multiple @file{configure.ac} files
2511 @cindex Invoking @command{automake}
2512 @cindex @command{automake}, invoking
2514 To create all the @file{Makefile.in}s for a package, run the
2515 @command{automake} program in the top level directory, with no
2516 arguments. @command{automake} will automatically find each
2517 appropriate @file{Makefile.am} (by scanning @file{configure.ac};
2518 @pxref{configure}) and generate the corresponding @file{Makefile.in}.
2519 Note that @command{automake} has a rather simplistic view of what
2520 constitutes a package; it assumes that a package has only one
2521 @file{configure.ac}, at the top. If your package has multiple
2522 @file{configure.ac}s, then you must run @command{automake} in each
2523 directory holding a @file{configure.ac}. (Alternatively, you may rely
2524 on Autoconf's @command{autoreconf}, which is able to recurse your
2525 package tree and run @command{automake} where appropriate.)
2527 You can optionally give @command{automake} an argument; @file{.am} is
2528 appended to the argument and the result is used as the name of the
2529 input file. This feature is generally only used to automatically
2530 rebuild an out-of-date @file{Makefile.in}. Note that
2531 @command{automake} must always be run from the topmost directory of a
2532 project, even if being used to regenerate the @file{Makefile.in} in
2533 some subdirectory. This is necessary because @command{automake} must
2534 scan @file{configure.ac}, and because @command{automake} uses the
2535 knowledge that a @file{Makefile.in} is in a subdirectory to change its
2536 behavior in some cases.
2539 Automake will run @command{autoconf} to scan @file{configure.ac} and
2540 its dependencies (i.e., @file{aclocal.m4} and any included file),
2541 therefore @command{autoconf} must be in your @env{PATH}. If there is
2542 an @env{AUTOCONF} variable in your environment it will be used
2543 instead of @command{autoconf}, this allows you to select a particular
2544 version of Autoconf. By the way, don't misunderstand this paragraph:
2545 @command{automake} runs @command{autoconf} to @strong{scan} your
2546 @file{configure.ac}, this won't build @file{configure} and you still
2547 have to run @command{autoconf} yourself for this purpose.
2549 @cindex @command{automake} options
2550 @cindex Options, @command{automake}
2551 @cindex Strictness, command line
2553 @command{automake} accepts the following options:
2555 @cindex Extra files distributed with Automake
2556 @cindex Files distributed with Automake
2557 @cindex @file{config.guess}
2561 @itemx --add-missing
2563 @opindex --add-missing
2564 Automake requires certain common files to exist in certain situations;
2565 for instance, @file{config.guess} is required if @file{configure.ac} invokes
2566 @code{AC_CANONICAL_HOST}. Automake is distributed with several of these
2567 files (@pxref{Auxiliary Programs}); this option will cause the missing
2568 ones to be automatically added to the package, whenever possible. In
2569 general if Automake tells you a file is missing, try using this option.
2570 By default Automake tries to make a symbolic link pointing to its own
2571 copy of the missing file; this can be changed with @option{--copy}.
2573 Many of the potentially-missing files are common scripts whose
2574 location may be specified via the @code{AC_CONFIG_AUX_DIR} macro.
2575 Therefore, @code{AC_CONFIG_AUX_DIR}'s setting affects whether a
2576 file is considered missing, and where the missing file is added
2579 In some strictness modes, additional files are installed, see @ref{Gnits}
2580 for more information.
2582 @item --libdir=@var{dir}
2584 Look for Automake data files in directory @var{dir} instead of in the
2585 installation directory. This is typically used for debugging.
2591 When used with @option{--add-missing}, causes installed files to be
2592 copied. The default is to make a symbolic link.
2596 Causes the generated @file{Makefile.in}s to follow Cygnus rules, instead
2597 of GNU or Gnits rules. For more information, see @ref{Cygnus}.
2601 @itemx --force-missing
2602 @opindex --force-missing
2603 When used with @option{--add-missing}, causes standard files to be reinstalled
2604 even if they already exist in the source tree. This involves removing
2605 the file from the source tree before creating the new symlink (or, with
2606 @option{--copy}, copying the new file).
2610 Set the global strictness to @option{foreign}. For more information, see
2615 Set the global strictness to @option{gnits}. For more information, see
2620 Set the global strictness to @option{gnu}. For more information, see
2621 @ref{Gnits}. This is the default strictness.
2625 Print a summary of the command line options and exit.
2628 @itemx --ignore-deps
2630 This disables the dependency tracking feature in generated
2631 @file{Makefile}s; see @ref{Dependencies}.
2633 @item --include-deps
2634 @opindex --include-deps
2635 This enables the dependency tracking feature. This feature is enabled
2636 by default. This option is provided for historical reasons only and
2637 probably should not be used.
2641 Ordinarily @command{automake} creates all @file{Makefile.in}s mentioned in
2642 @file{configure.ac}. This option causes it to only update those
2643 @file{Makefile.in}s that are out of date with respect to one of their
2647 @itemx --output-dir=@var{dir}
2649 @opindex --output-dir
2650 Put the generated @file{Makefile.in} in the directory @var{dir}.
2651 Ordinarily each @file{Makefile.in} is created in the directory of the
2652 corresponding @file{Makefile.am}. This option is deprecated and will be
2653 removed in a future release.
2659 Cause Automake to print information about which files are being read or
2664 Print the version number of Automake and exit.
2667 @itemx --warnings=@var{category}
2670 Output warnings falling in @var{category}. @var{category} can be
2674 warnings related to the GNU Coding Standards
2675 (@pxref{Top, , , standards, The GNU Coding Standards}).
2677 obsolete features or constructions
2679 user redefinitions of Automake rules or variables
2681 portability issues (e.g., use of @command{make} features that are
2682 known to be not portable)
2683 @item extra-portability
2684 extra portability issues related to obscure tools. One example of such
2685 a tool is the Microsoft @command{lib} archiver.
2687 weird syntax, unused variables, typos
2689 unsupported or incomplete features
2693 turn off all the warnings
2695 treat warnings as errors
2698 A category can be turned off by prefixing its name with @samp{no-}. For
2699 instance, @option{-Wno-syntax} will hide the warnings about unused
2702 The categories output by default are @samp{syntax} and
2703 @samp{unsupported}. Additionally, @samp{gnu} and @samp{portability}
2704 are enabled in @option{--gnu} and @option{--gnits} strictness.
2705 On the other hand, the @option{silent-rules} options (@pxref{Options})
2706 turns off portability warnings about recursive variable expansions.
2708 @c Checked by extra-portability.test
2709 Turning off @samp{portability} will also turn off @samp{extra-portability},
2710 and similarly turning on @samp{extra-portability} will also turn on
2711 @samp{portability}. However, turning on @samp{portability} or turning
2712 off @samp{extra-portability} will not affect the other category.
2715 The environment variable @env{WARNINGS} can contain a comma separated
2716 list of categories to enable. It will be taken into account before the
2717 command-line switches, this way @option{-Wnone} will also ignore any
2718 warning category enabled by @env{WARNINGS}. This variable is also used
2719 by other tools like @command{autoconf}; unknown categories are ignored
2724 @vindex AUTOMAKE_JOBS
2725 If the environment variable @env{AUTOMAKE_JOBS} contains a positive
2726 number, it is taken as the maximum number of Perl threads to use in
2727 @command{automake} for generating multiple @file{Makefile.in} files
2728 concurrently. This is an experimental feature.
2732 @chapter Scanning @file{configure.ac}, using @command{aclocal}
2734 @cindex @file{configure.ac}, scanning
2735 @cindex Scanning @file{configure.ac}
2736 @cindex Using @command{aclocal}
2737 @cindex @command{aclocal}, using
2739 Automake scans the package's @file{configure.ac} to determine certain
2740 information about the package. Some @command{autoconf} macros are required
2741 and some variables must be defined in @file{configure.ac}. Automake
2742 will also use information from @file{configure.ac} to further tailor its
2745 Automake also supplies some Autoconf macros to make the maintenance
2746 easier. These macros can automatically be put into your
2747 @file{aclocal.m4} using the @command{aclocal} program.
2750 * Requirements:: Configuration requirements
2751 * Optional:: Other things Automake recognizes
2752 * Invoking aclocal:: Auto-generating aclocal.m4
2753 * Macros:: Autoconf macros supplied with Automake
2758 @section Configuration requirements
2760 @cindex Automake requirements
2761 @cindex Requirements of Automake
2763 @acindex AM_INIT_AUTOMAKE
2764 The one real requirement of Automake is that your @file{configure.ac}
2765 call @code{AM_INIT_AUTOMAKE}. This macro does several things that are
2766 required for proper Automake operation (@pxref{Macros}).
2768 Here are the other macros that Automake requires but which are not run
2769 by @code{AM_INIT_AUTOMAKE}:
2772 @item AC_CONFIG_FILES
2774 @acindex AC_CONFIG_FILES
2776 These two macros are usually invoked as follows near the end of
2777 @file{configure.ac}.
2791 Automake uses these to determine which files to create (@pxref{Output, ,
2792 Creating Output Files, autoconf, The Autoconf Manual}). A listed file
2793 is considered to be an Automake generated @file{Makefile} if there
2794 exists a file with the same name and the @file{.am} extension appended.
2795 Typically, @samp{AC_CONFIG_FILES([foo/Makefile])} will cause Automake to
2796 generate @file{foo/Makefile.in} if @file{foo/Makefile.am} exists.
2798 When using @code{AC_CONFIG_FILES} with multiple input files, as in
2801 AC_CONFIG_FILES([Makefile:top.in:Makefile.in:bot.in])
2805 @command{automake} will generate the first @file{.in} input file for
2806 which a @file{.am} file exists. If no such file exists the output
2807 file is not considered to be generated by Automake.
2809 Files created by @code{AC_CONFIG_FILES}, be they Automake
2810 @file{Makefile}s or not, are all removed by @samp{make distclean}.
2811 Their inputs are automatically distributed, unless they
2812 are the output of prior @code{AC_CONFIG_FILES} commands.
2813 Finally, rebuild rules are generated in the Automake @file{Makefile}
2814 existing in the subdirectory of the output file, if there is one, or
2815 in the top-level @file{Makefile} otherwise.
2817 The above machinery (cleaning, distributing, and rebuilding) works
2818 fine if the @code{AC_CONFIG_FILES} specifications contain only
2819 literals. If part of the specification uses shell variables,
2820 @command{automake} will not be able to fulfill this setup, and you will
2821 have to complete the missing bits by hand. For instance, on
2823 @c Keep in sync with output11.test.
2827 AC_CONFIG_FILES([output:$file],, [file=$file])
2831 @command{automake} will output rules to clean @file{output}, and
2832 rebuild it. However the rebuild rule will not depend on @file{input},
2833 and this file will not be distributed either. (You must add
2834 @samp{EXTRA_DIST = input} to your @file{Makefile.am} if @file{input} is a
2839 @c Keep in sync with output11.test.
2844 AC_CONFIG_FILES([$file:input],, [file=$file])
2845 AC_CONFIG_FILES([$file2],, [file2=$file2])
2849 will only cause @file{input} to be distributed. No file will be
2850 cleaned automatically (add @samp{DISTCLEANFILES = output out}
2851 yourself), and no rebuild rule will be output.
2853 Obviously @command{automake} cannot guess what value @samp{$file} is
2854 going to hold later when @file{configure} is run, and it cannot use
2855 the shell variable @samp{$file} in a @file{Makefile}. However, if you
2856 make reference to @samp{$file} as @samp{$@{file@}} (i.e., in a way
2857 that is compatible with @command{make}'s syntax) and furthermore use
2858 @code{AC_SUBST} to ensure that @samp{$@{file@}} is meaningful in a
2859 @file{Makefile}, then @command{automake} will be able to use
2860 @samp{$@{file@}} to generate all these rules. For instance, here is
2861 how the Automake package itself generates versioned scripts for its
2865 AC_SUBST([APIVERSION], @dots{})
2868 [tests/aclocal-$@{APIVERSION@}:tests/aclocal.in],
2869 [chmod +x tests/aclocal-$@{APIVERSION@}],
2870 [APIVERSION=$APIVERSION])
2872 [tests/automake-$@{APIVERSION@}:tests/automake.in],
2873 [chmod +x tests/automake-$@{APIVERSION@}])
2877 Here cleaning, distributing, and rebuilding are done automatically,
2878 because @samp{$@{APIVERSION@}} is known at @command{make}-time.
2880 Note that you should not use shell variables to declare
2881 @file{Makefile} files for which @command{automake} must create
2882 @file{Makefile.in}. Even @code{AC_SUBST} does not help here, because
2883 @command{automake} needs to know the file name when it runs in order
2884 to check whether @file{Makefile.am} exists. (In the very hairy case
2885 that your setup requires such use of variables, you will have to tell
2886 Automake which @file{Makefile.in}s to generate on the command-line.)
2888 It is possible to let @command{automake} emit conditional rules for
2889 @code{AC_CONFIG_FILES} with the help of @code{AM_COND_IF}
2895 Use literals for @file{Makefile}s, and for other files whenever possible.
2897 Use @samp{$file} (or @samp{$@{file@}} without @samp{AC_SUBST([file])})
2898 for files that @command{automake} should ignore.
2900 Use @samp{$@{file@}} and @samp{AC_SUBST([file])} for files
2901 that @command{automake} should not ignore.
2908 @section Other things Automake recognizes
2910 @cindex Macros Automake recognizes
2911 @cindex Recognized macros by Automake
2913 Every time Automake is run it calls Autoconf to trace
2914 @file{configure.ac}. This way it can recognize the use of certain
2915 macros and tailor the generated @file{Makefile.in} appropriately.
2916 Currently recognized macros and their effects are:
2919 @item AC_CANONICAL_BUILD
2920 @itemx AC_CANONICAL_HOST
2921 @itemx AC_CANONICAL_TARGET
2922 @vindex build_triplet
2923 @vindex host_triplet
2924 @vindex target_triplet
2925 Automake will ensure that @file{config.guess} and @file{config.sub}
2926 exist. Also, the @file{Makefile} variables @code{build_triplet},
2927 @code{host_triplet} and @code{target_triplet} are introduced. See
2928 @ref{Canonicalizing, , Getting the Canonical System Type, autoconf,
2929 The Autoconf Manual}.
2931 @item AC_CONFIG_AUX_DIR
2932 Automake will look for various helper scripts, such as
2933 @file{install-sh}, in the directory named in this macro invocation.
2934 @c This list is accurate relative to version 1.8
2935 (The full list of scripts is: @file{ar-lib}, @file{config.guess},
2936 @file{config.sub}, @file{depcomp}, @file{elisp-comp}, @file{compile},
2937 @file{install-sh}, @file{ltmain.sh}, @file{mdate-sh}, @file{missing},
2938 @file{mkinstalldirs}, @file{py-compile}, @file{texinfo.tex}, and
2939 @file{ylwrap}.) Not all scripts are always searched for; some scripts
2940 will only be sought if the generated @file{Makefile.in} requires them.
2942 If @code{AC_CONFIG_AUX_DIR} is not given, the scripts are looked for in
2943 their standard locations. For @file{mdate-sh},
2944 @file{texinfo.tex}, and @file{ylwrap}, the standard location is the
2945 source directory corresponding to the current @file{Makefile.am}. For
2946 the rest, the standard location is the first one of @file{.}, @file{..},
2947 or @file{../..} (relative to the top source directory) that provides any
2948 one of the helper scripts. @xref{Input, , Finding `configure' Input,
2949 autoconf, The Autoconf Manual}.
2951 Required files from @code{AC_CONFIG_AUX_DIR} are automatically
2952 distributed, even if there is no @file{Makefile.am} in this directory.
2954 @item AC_CONFIG_LIBOBJ_DIR
2955 Automake will require the sources file declared with
2956 @code{AC_LIBSOURCE} (see below) in the directory specified by this
2959 @item AC_CONFIG_HEADERS
2960 Automake will generate rules to rebuild these headers. Older versions
2961 of Automake required the use of @code{AM_CONFIG_HEADER}
2962 (@pxref{Macros}); this is no longer the case.
2964 As with @code{AC_CONFIG_FILES} (@pxref{Requirements}), parts of the
2965 specification using shell variables will be ignored as far as
2966 cleaning, distributing, and rebuilding is concerned.
2968 @item AC_CONFIG_LINKS
2969 Automake will generate rules to remove @file{configure} generated
2970 links on @samp{make distclean} and to distribute named source files as
2971 part of @samp{make dist}.
2973 As for @code{AC_CONFIG_FILES} (@pxref{Requirements}), parts of the
2974 specification using shell variables will be ignored as far as cleaning
2975 and distributing is concerned. (There are no rebuild rules for links.)
2979 @itemx AC_LIBSOURCES
2981 Automake will automatically distribute any file listed in
2982 @code{AC_LIBSOURCE} or @code{AC_LIBSOURCES}.
2984 Note that the @code{AC_LIBOBJ} macro calls @code{AC_LIBSOURCE}. So if
2985 an Autoconf macro is documented to call @samp{AC_LIBOBJ([file])}, then
2986 @file{file.c} will be distributed automatically by Automake. This
2987 encompasses many macros like @code{AC_FUNC_ALLOCA},
2988 @code{AC_FUNC_MEMCMP}, @code{AC_REPLACE_FUNCS}, and others.
2990 By the way, direct assignments to @code{LIBOBJS} are no longer
2991 supported. You should always use @code{AC_LIBOBJ} for this purpose.
2992 @xref{AC_LIBOBJ vs LIBOBJS, , @code{AC_LIBOBJ} vs.@: @code{LIBOBJS},
2993 autoconf, The Autoconf Manual}.
2995 @item AC_PROG_RANLIB
2996 This is required if any libraries are built in the package.
2997 @xref{Particular Programs, , Particular Program Checks, autoconf, The
3001 This is required if any C++ source is included. @xref{Particular
3002 Programs, , Particular Program Checks, autoconf, The Autoconf Manual}.
3005 This is required if any Objective C source is included. @xref{Particular
3006 Programs, , Particular Program Checks, autoconf, The Autoconf Manual}.
3009 This is required if any Fortran 77 source is included. This macro is
3010 distributed with Autoconf version 2.13 and later. @xref{Particular
3011 Programs, , Particular Program Checks, autoconf, The Autoconf Manual}.
3013 @item AC_F77_LIBRARY_LDFLAGS
3014 This is required for programs and shared libraries that are a mixture of
3015 languages that include Fortran 77 (@pxref{Mixing Fortran 77 With C and
3016 C++}). @xref{Macros, , Autoconf macros supplied with Automake}.
3019 Automake will add the flags computed by @code{AC_FC_SRCEXT} to compilation
3020 of files with the respective source extension (@pxref{Fortran Compiler, ,
3021 Fortran Compiler Characteristics, autoconf, The Autoconf Manual}).
3024 This is required if any Fortran 90/95 source is included. This macro is
3025 distributed with Autoconf version 2.58 and later. @xref{Particular
3026 Programs, , Particular Program Checks, autoconf, The Autoconf Manual}.
3028 @item AC_PROG_LIBTOOL
3029 Automake will turn on processing for @command{libtool} (@pxref{Top, ,
3030 Introduction, libtool, The Libtool Manual}).
3034 If a Yacc source file is seen, then you must either use this macro or
3035 define the variable @code{YACC} in @file{configure.ac}. The former is
3036 preferred (@pxref{Particular Programs, , Particular Program Checks,
3037 autoconf, The Autoconf Manual}).
3040 If a Lex source file is seen, then this macro must be used.
3041 @xref{Particular Programs, , Particular Program Checks, autoconf, The
3044 @item AC_REQUIRE_AUX_FILE
3045 For each @code{AC_REQUIRE_AUX_FILE([@var{file}])},
3046 @command{automake} will ensure that @file{@var{file}} exists in the
3047 aux directory, and will complain otherwise. It
3048 will also automatically distribute the file. This macro should be
3049 used by third-party Autoconf macros that require some supporting
3050 files in the aux directory specified with @code{AC_CONFIG_AUX_DIR}
3051 above. @xref{Input, , Finding @command{configure} Input, autoconf,
3052 The Autoconf Manual}.
3055 The first argument is automatically defined as a variable in each
3056 generated @file{Makefile.in}, unless @code{AM_SUBST_NOTMAKE} is also
3057 used for this variable. @xref{Setting Output Variables, , Setting
3058 Output Variables, autoconf, The Autoconf Manual}.
3060 For every substituted variable @var{var}, @command{automake} will add
3061 a line @code{@var{var} = @var{value}} to each @file{Makefile.in} file.
3062 Many Autoconf macros invoke @code{AC_SUBST} to set output variables
3063 this way, e.g., @code{AC_PATH_XTRA} defines @code{X_CFLAGS} and
3064 @code{X_LIBS}. Thus, you can access these variables as
3065 @code{$(X_CFLAGS)} and @code{$(X_LIBS)} in any @file{Makefile.am}
3066 if @code{AC_PATH_XTRA} is called.
3068 @item AM_C_PROTOTYPES
3069 This is required when using the deprecated de-ANSI-fication feature;
3070 @pxref{ANSI}. @emph{It will be removed} in the next major Automake
3073 @item AM_CONDITIONAL
3074 This introduces an Automake conditional (@pxref{Conditionals}).
3077 This macro allows @code{automake} to detect subsequent access within
3078 @file{configure.ac} to a conditional previously introduced with
3079 @code{AM_CONDITIONAL}, thus enabling conditional @code{AC_CONFIG_FILES}
3080 (@pxref{Usage of Conditionals}).
3082 @item AM_GNU_GETTEXT
3083 This macro is required for packages that use GNU gettext
3084 (@pxref{gettext}). It is distributed with gettext. If Automake sees
3085 this macro it ensures that the package meets some of gettext's
3088 @item AM_GNU_GETTEXT_INTL_SUBDIR
3089 This macro specifies that the @file{intl/} subdirectory is to be built,
3090 even if the @code{AM_GNU_GETTEXT} macro was invoked with a first argument
3093 @item AM_MAINTAINER_MODE(@ovar{default-mode})
3094 @opindex --enable-maintainer-mode
3095 @opindex --disable-maintainer-mode
3096 This macro adds an @option{--enable-maintainer-mode} option to
3097 @command{configure}. If this is used, @command{automake} will cause
3098 ``maintainer-only'' rules to be turned off by default in the
3099 generated @file{Makefile.in}s, unless @var{default-mode} is
3100 @samp{enable}. This macro defines the @code{MAINTAINER_MODE}
3101 conditional, which you can use in your own @file{Makefile.am}.
3102 @xref{maintainer-mode}.
3104 @item AM_SUBST_NOTMAKE(@var{var})
3105 Prevent Automake from defining a variable @var{var}, even if it is
3106 substituted by @command{config.status}. Normally, Automake defines a
3107 @command{make} variable for each @command{configure} substitution,
3108 i.e., for each @code{AC_SUBST([@var{var}])}. This macro prevents that
3109 definition from Automake. If @code{AC_SUBST} has not been called
3110 for this variable, then @code{AM_SUBST_NOTMAKE} has no effects.
3111 Preventing variable definitions may be useful for substitution of
3112 multi-line values, where @code{@var{var} = @@@var{value}@@} might yield
3116 Files included by @file{configure.ac} using this macro will be
3117 detected by Automake and automatically distributed. They will also
3118 appear as dependencies in @file{Makefile} rules.
3120 @code{m4_include} is seldom used by @file{configure.ac} authors, but
3121 can appear in @file{aclocal.m4} when @command{aclocal} detects that
3122 some required macros come from files local to your package (as opposed
3123 to macros installed in a system-wide directory, @pxref{Invoking
3129 @node Invoking aclocal
3130 @section Auto-generating aclocal.m4
3132 @cindex Invoking @command{aclocal}
3133 @cindex @command{aclocal}, Invoking
3135 Automake includes a number of Autoconf macros that can be used in
3136 your package (@pxref{Macros}); some of them are actually required by
3137 Automake in certain situations. These macros must be defined in your
3138 @file{aclocal.m4}; otherwise they will not be seen by
3141 The @command{aclocal} program will automatically generate
3142 @file{aclocal.m4} files based on the contents of @file{configure.ac}.
3143 This provides a convenient way to get Automake-provided macros,
3144 without having to search around. The @command{aclocal} mechanism
3145 allows other packages to supply their own macros (@pxref{Extending
3146 aclocal}). You can also use it to maintain your own set of custom
3147 macros (@pxref{Local Macros}).
3149 At startup, @command{aclocal} scans all the @file{.m4} files it can
3150 find, looking for macro definitions (@pxref{Macro Search Path}). Then
3151 it scans @file{configure.ac}. Any mention of one of the macros found
3152 in the first step causes that macro, and any macros it in turn
3153 requires, to be put into @file{aclocal.m4}.
3155 @emph{Putting} the file that contains the macro definition into
3156 @file{aclocal.m4} is usually done by copying the entire text of this
3157 file, including unused macro definitions as well as both @samp{#} and
3158 @samp{dnl} comments. If you want to make a comment that will be
3159 completely ignored by @command{aclocal}, use @samp{##} as the comment
3162 When a file selected by @command{aclocal} is located in a subdirectory
3163 specified as a relative search path with @command{aclocal}'s @option{-I}
3164 argument, @command{aclocal} assumes the file belongs to the package
3165 and uses @code{m4_include} instead of copying it into
3166 @file{aclocal.m4}. This makes the package smaller, eases dependency
3167 tracking, and cause the file to be distributed automatically.
3168 (@xref{Local Macros}, for an example.) Any macro that is found in a
3169 system-wide directory, or via an absolute search path will be copied.
3170 So use @samp{-I `pwd`/reldir} instead of @samp{-I reldir} whenever
3171 some relative directory should be considered outside the package.
3173 The contents of @file{acinclude.m4}, if this file exists, are also
3174 automatically included in @file{aclocal.m4}. We recommend against
3175 using @file{acinclude.m4} in new packages (@pxref{Local Macros}).
3179 While computing @file{aclocal.m4}, @command{aclocal} runs
3180 @command{autom4te} (@pxref{Using autom4te, , Using @command{Autom4te},
3181 autoconf, The Autoconf Manual}) in order to trace the macros that are
3182 really used, and omit from @file{aclocal.m4} all macros that are
3183 mentioned but otherwise unexpanded (this can happen when a macro is
3184 called conditionally). @command{autom4te} is expected to be in the
3185 @env{PATH}, just as @command{autoconf}. Its location can be
3186 overridden using the @env{AUTOM4TE} environment variable.
3189 * aclocal Options:: Options supported by aclocal
3190 * Macro Search Path:: How aclocal finds .m4 files
3191 * Extending aclocal:: Writing your own aclocal macros
3192 * Local Macros:: Organizing local macros
3193 * Serials:: Serial lines in Autoconf macros
3194 * Future of aclocal:: aclocal's scheduled death
3197 @node aclocal Options
3198 @subsection aclocal Options
3200 @cindex @command{aclocal}, Options
3201 @cindex Options, @command{aclocal}
3203 @command{aclocal} accepts the following options:
3206 @item --automake-acdir=@var{dir}
3207 @opindex --automake-acdir
3208 Look for the automake-provided macro files in @var{dir} instead of
3209 in the installation directory. This is typically used for debugging.
3211 @item --system-acdir=@var{dir}
3212 @opindex --system-acdir
3213 Look for the system-wide third-party macro files (and the special
3214 @file{dirlist} file) in @var{dir} instead of in the installation
3215 directory. This is typically used for debugging.
3217 @item --acdir=@var{dir}
3219 @emph{Deprecated} shorthand for ``@option{--automake-acdir=@var{dir}
3220 --system-acdir=@var{dir}}''. Will be removed in future aclocal versions.
3222 @item --diff[=@var{command}]
3224 Run @var{command} on M4 file that would be installed or overwritten
3225 by @option{--install}. The default @var{command} is @samp{diff -u}.
3226 This option implies @option{--install} and @option{--dry-run}.
3230 Do not actually overwrite (or create) @file{aclocal.m4} and M4
3231 files installed by @option{--install}.
3235 Print a summary of the command line options and exit.
3239 Add the directory @var{dir} to the list of directories searched for
3244 Install system-wide third-party macros into the first directory
3245 specified with @samp{-I @var{dir}} instead of copying them in the
3248 @cindex serial number and @option{--install}
3249 When this option is used, and only when this option is used,
3250 @command{aclocal} will also honor @samp{#serial @var{number}} lines
3251 that appear in macros: an M4 file is ignored if there exists another
3252 M4 file with the same basename and a greater serial number in the
3253 search path (@pxref{Serials}).
3257 Always overwrite the output file. The default is to overwrite the output
3258 file only when really needed, i.e., when its contents changes or if one
3259 of its dependencies is younger.
3261 This option forces the update of @file{aclocal.m4} (or the file
3262 specified with @file{--output} below) and only this file, it has
3263 absolutely no influence on files that may need to be installed by
3266 @item --output=@var{file}
3268 Cause the output to be put into @var{file} instead of @file{aclocal.m4}.
3270 @item --print-ac-dir
3271 @opindex --print-ac-dir
3272 Prints the name of the directory that @command{aclocal} will search to
3273 find third-party @file{.m4} files. When this option is given, normal
3274 processing is suppressed. This option was used @emph{in the past} by
3275 third-party packages to determine where to install @file{.m4} macro
3276 files, but @emph{this usage is today discouraged}, since it causes
3277 @samp{$(prefix)} not to be thoroughly honoured (which violates the
3278 GNU Coding Standards), and a similar semantics can be better obtained
3279 with the @env{ACLOCAL_PATH} environment variable; @pxref{Extending aclocal}.
3283 Print the names of the files it examines.
3287 Print the version number of Automake and exit.
3290 @item --warnings=@var{category}
3293 Output warnings falling in @var{category}. @var{category} can be
3297 dubious syntactic constructs, underquoted macros, unused macros, etc.
3301 all the warnings, this is the default
3303 turn off all the warnings
3305 treat warnings as errors
3308 All warnings are output by default.
3311 The environment variable @env{WARNINGS} is honored in the same
3312 way as it is for @command{automake} (@pxref{Invoking Automake}).
3316 @node Macro Search Path
3317 @subsection Macro Search Path
3319 @cindex Macro search path
3320 @cindex @command{aclocal} search path
3322 By default, @command{aclocal} searches for @file{.m4} files in the following
3323 directories, in this order:
3326 @item @var{acdir-APIVERSION}
3327 This is where the @file{.m4} macros distributed with Automake itself
3328 are stored. @var{APIVERSION} depends on the Automake release used;
3329 for example, for Automake 1.11.x, @var{APIVERSION} = @code{1.11}.
3332 This directory is intended for third party @file{.m4} files, and is
3333 configured when @command{automake} itself is built. This is
3334 @file{@@datadir@@/aclocal/}, which typically
3335 expands to @file{$@{prefix@}/share/aclocal/}. To find the compiled-in
3336 value of @var{acdir}, use the @option{--print-ac-dir} option
3337 (@pxref{aclocal Options}).
3340 As an example, suppose that @command{automake-1.11.2} was configured with
3341 @option{--prefix=@-/usr/local}. Then, the search path would be:
3344 @item @file{/usr/local/share/aclocal-1.11.2/}
3345 @item @file{/usr/local/share/aclocal/}
3348 The paths for the @var{acdir} and @var{acdir-APIVERSION} directories can
3349 be changed respectively through aclocal options @option{--system-acdir}
3350 and @option{--automake-acdir} (@pxref{aclocal Options}). Note however
3351 that these options are only intended for use by the internal Automake
3352 test suite, or for debugging under highly unusual situations; they are
3353 not ordinarily needed by end-users.
3355 As explained in (@pxref{aclocal Options}), there are several options that
3356 can be used to change or extend this search path.
3358 @subsubheading Modifying the Macro Search Path: @samp{-I @var{dir}}
3360 Any extra directories specified using @option{-I} options
3361 (@pxref{aclocal Options}) are @emph{prepended} to this search list. Thus,
3362 @samp{aclocal -I /foo -I /bar} results in the following search path:
3367 @item @var{acdir}-@var{APIVERSION}
3371 @subsubheading Modifying the Macro Search Path: @file{dirlist}
3372 @cindex @file{dirlist}
3374 There is a third mechanism for customizing the search path. If a
3375 @file{dirlist} file exists in @var{acdir}, then that file is assumed to
3376 contain a list of directory patterns, one per line. @command{aclocal}
3377 expands these patterns to directory names, and adds them to the search
3378 list @emph{after} all other directories. @file{dirlist} entries may
3379 use shell wildcards such as @samp{*}, @samp{?}, or @code{[...]}.
3381 For example, suppose
3382 @file{@var{acdir}/dirlist} contains the following:
3391 and that @command{aclocal} was called with the @samp{-I /foo -I /bar} options.
3392 Then, the search path would be
3394 @c @code looks better than @file here
3398 @item @var{acdir}-@var{APIVERSION}
3405 and all directories with path names starting with @code{/test3}.
3407 If the @option{--system-acdir=@var{dir}} option is used, then
3408 @command{aclocal} will search for the @file{dirlist} file in
3409 @var{dir}; but remember the warnings above against the use of
3410 @option{--system-acdir}.
3412 @file{dirlist} is useful in the following situation: suppose that
3413 @command{automake} version @code{1.11.2} is installed with
3414 @samp{--prefix=/usr} by the system vendor. Thus, the default search
3417 @c @code looks better than @file here
3419 @item @code{/usr/share/aclocal-1.11/}
3420 @item @code{/usr/share/aclocal/}
3423 However, suppose further that many packages have been manually
3424 installed on the system, with $prefix=/usr/local, as is typical. In
3425 that case, many of these ``extra'' @file{.m4} files are in
3426 @file{/usr/local/share/aclocal}. The only way to force
3427 @file{/usr/bin/aclocal} to find these ``extra'' @file{.m4} files is to
3428 always call @samp{aclocal -I /usr/local/share/aclocal}. This is
3429 inconvenient. With @file{dirlist}, one may create a file
3430 @file{/usr/share/aclocal/dirlist} containing only the single line
3433 /usr/local/share/aclocal
3436 Now, the ``default'' search path on the affected system is
3438 @c @code looks better than @file here
3440 @item @code{/usr/share/aclocal-1.11/}
3441 @item @code{/usr/share/aclocal/}
3442 @item @code{/usr/local/share/aclocal/}
3445 without the need for @option{-I} options; @option{-I} options can be reserved
3446 for project-specific needs (@file{my-source-dir/m4/}), rather than
3447 using it to work around local system-dependent tool installation
3450 Similarly, @file{dirlist} can be handy if you have installed a local
3451 copy of Automake in your account and want @command{aclocal} to look for
3452 macros installed at other places on the system.
3454 @anchor{ACLOCAL_PATH}
3455 @subsubheading Modifying the Macro Search Path: @file{ACLOCAL_PATH}
3456 @cindex @env{ACLOCAL_PATH}
3458 The fourth and last mechanism to customize the macro search path is
3459 also the simplest. Any directory included in the colon-separated
3460 environment variable @env{ACLOCAL_PATH} is added to the search path
3461 @c Keep in sync with aclocal-path-precedence.test.
3462 and takes precedence over system directories (including those found via
3463 @file{dirlist}), with the exception of the versioned directory
3464 @var{acdir-APIVERSION} (@pxref{Macro Search Path}). However, directories
3465 passed via @option{-I} will take precedence over directories in
3468 @c Keep in sync with aclocal-path-installed.test.
3469 Also note that, if the @option{--install} option is used, any @file{.m4}
3470 file containing a required macro that is found in a directory listed in
3471 @env{ACLOCAL_PATH} will be installed locally.
3472 @c Keep in sync with aclocal-path-installed-serial.test.
3473 In this case, serial numbers in @file{.m4} are honoured too,
3476 Conversely to @file{dirlist}, @env{ACLOCAL_PATH} is useful if you are
3477 using a global copy of Automake and want @command{aclocal} to look for
3478 macros somewhere under your home directory.
3480 @subsubheading Planned future incompatibilities
3482 The order in which the directories in the macro search path are currently
3483 looked up is confusing and/or suboptimal in various aspects, and is
3484 probably going to be changed in the future Automake release. In
3485 particular, directories in @env{ACLOCAL_PATH} and @file{@var{acdir}}
3486 might end up taking precedence over @file{@var{acdir-APIVERSION}}, and
3487 directories in @file{@var{acdir}/dirlist} might end up taking precedence
3488 over @file{@var{acdir}}. @emph{This is a possible future incompatibility!}
3490 @node Extending aclocal
3491 @subsection Writing your own aclocal macros
3493 @cindex @command{aclocal}, extending
3494 @cindex Extending @command{aclocal}
3496 The @command{aclocal} program doesn't have any built-in knowledge of any
3497 macros, so it is easy to extend it with your own macros.
3499 This can be used by libraries that want to supply their own Autoconf
3500 macros for use by other programs. For instance, the @command{gettext}
3501 library supplies a macro @code{AM_GNU_GETTEXT} that should be used by
3502 any package using @command{gettext}. When the library is installed, it
3503 installs this macro so that @command{aclocal} will find it.
3505 A macro file's name should end in @file{.m4}. Such files should be
3506 installed in @file{$(datadir)/aclocal}. This is as simple as writing:
3508 @c Keep in sync with primary-prefix-couples-documented-valid.test.
3510 aclocaldir = $(datadir)/aclocal
3511 aclocal_DATA = mymacro.m4 myothermacro.m4
3515 Please do use @file{$(datadir)/aclocal}, and not something based on
3516 the result of @samp{aclocal --print-ac-dir} (@pxref{Hard-Coded Install
3517 Paths}, for arguments). It might also be helpful to suggest to
3518 the user to add the @file{$(datadir)/aclocal} directory to his
3519 @env{ACLOCAL_PATH} variable (@pxref{ACLOCAL_PATH}) so that
3520 @command{aclocal} will find the @file{.m4} files installed by your
3521 package automatically.
3523 A file of macros should be a series of properly quoted
3524 @code{AC_DEFUN}'s (@pxref{Macro Definitions, , , autoconf, The
3525 Autoconf Manual}). The @command{aclocal} programs also understands
3526 @code{AC_REQUIRE} (@pxref{Prerequisite Macros, , , autoconf, The
3527 Autoconf Manual}), so it is safe to put each macro in a separate file.
3528 Each file should have no side effects but macro definitions.
3529 Especially, any call to @code{AC_PREREQ} should be done inside the
3530 defined macro, not at the beginning of the file.
3532 @cindex underquoted @code{AC_DEFUN}
3536 Starting with Automake 1.8, @command{aclocal} will warn about all
3537 underquoted calls to @code{AC_DEFUN}. We realize this will annoy a
3538 lot of people, because @command{aclocal} was not so strict in the past
3539 and many third party macros are underquoted; and we have to apologize
3540 for this temporary inconvenience. The reason we have to be stricter
3541 is that a future implementation of @command{aclocal} (@pxref{Future of
3542 aclocal}) will have to temporarily include all these third party
3543 @file{.m4} files, maybe several times, including even files that are
3544 not actually needed. Doing so should alleviate many problems of the
3545 current implementation, however it requires a stricter style from the
3546 macro authors. Hopefully it is easy to revise the existing macros.
3553 [AC_REQUIRE([AX_SOMETHING])dnl
3560 should be rewritten as
3563 AC_DEFUN([AX_FOOBAR],
3564 [AC_PREREQ([2.57])dnl
3565 AC_REQUIRE([AX_SOMETHING])dnl
3571 Wrapping the @code{AC_PREREQ} call inside the macro ensures that
3572 Autoconf 2.57 will not be required if @code{AX_FOOBAR} is not actually
3573 used. Most importantly, quoting the first argument of @code{AC_DEFUN}
3574 allows the macro to be redefined or included twice (otherwise this
3575 first argument would be expanded during the second definition). For
3576 consistency we like to quote even arguments such as @code{2.57} that
3579 If you have been directed here by the @command{aclocal} diagnostic but
3580 are not the maintainer of the implicated macro, you will want to
3581 contact the maintainer of that macro. Please make sure you have the
3582 latest version of the macro and that the problem hasn't already been
3583 reported before doing so: people tend to work faster when they aren't
3586 Another situation where @command{aclocal} is commonly used is to
3587 manage macros that are used locally by the package, @ref{Local
3591 @subsection Handling Local Macros
3593 Feature tests offered by Autoconf do not cover all needs. People
3594 often have to supplement existing tests with their own macros, or
3595 with third-party macros.
3597 There are two ways to organize custom macros in a package.
3599 The first possibility (the historical practice) is to list all your
3600 macros in @file{acinclude.m4}. This file will be included in
3601 @file{aclocal.m4} when you run @command{aclocal}, and its macro(s) will
3602 henceforth be visible to @command{autoconf}. However if it contains
3603 numerous macros, it will rapidly become difficult to maintain, and it
3604 will be almost impossible to share macros between packages.
3606 @vindex ACLOCAL_AMFLAGS
3607 The second possibility, which we do recommend, is to write each macro
3608 in its own file and gather all these files in a directory. This
3609 directory is usually called @file{m4/}. To build @file{aclocal.m4},
3610 one should therefore instruct @command{aclocal} to scan @file{m4/}.
3611 From the command line, this is done with @samp{aclocal -I m4}. The
3612 top-level @file{Makefile.am} should also be updated to define
3615 ACLOCAL_AMFLAGS = -I m4
3618 @code{ACLOCAL_AMFLAGS} contains options to pass to @command{aclocal}
3619 when @file{aclocal.m4} is to be rebuilt by @command{make}. This line is
3620 also used by @command{autoreconf} (@pxref{autoreconf Invocation, ,
3621 Using @command{autoreconf} to Update @file{configure} Scripts,
3622 autoconf, The Autoconf Manual}) to run @command{aclocal} with suitable
3623 options, or by @command{autopoint} (@pxref{autopoint Invocation, ,
3624 Invoking the @command{autopoint} Program, gettext, GNU gettext tools})
3625 and @command{gettextize} (@pxref{gettextize Invocation, , Invoking the
3626 @command{gettextize} Program, gettext, GNU gettext tools}) to locate
3627 the place where Gettext's macros should be installed. So even if you
3628 do not really care about the rebuild rules, you should define
3629 @code{ACLOCAL_AMFLAGS}.
3631 When @samp{aclocal -I m4} is run, it will build an @file{aclocal.m4}
3632 that @code{m4_include}s any file from @file{m4/} that defines a
3633 required macro. Macros not found locally will still be searched in
3634 system-wide directories, as explained in @ref{Macro Search Path}.
3636 Custom macros should be distributed for the same reason that
3637 @file{configure.ac} is: so that other people have all the sources of
3638 your package if they want to work on it. Actually, this distribution
3639 happens automatically because all @code{m4_include}d files are
3642 However there is no consensus on the distribution of third-party
3643 macros that your package may use. Many libraries install their own
3644 macro in the system-wide @command{aclocal} directory (@pxref{Extending
3645 aclocal}). For instance, Guile ships with a file called
3646 @file{guile.m4} that contains the macro @code{GUILE_FLAGS} that can
3647 be used to define setup compiler and linker flags appropriate for
3648 using Guile. Using @code{GUILE_FLAGS} in @file{configure.ac} will
3649 cause @command{aclocal} to copy @file{guile.m4} into
3650 @file{aclocal.m4}, but as @file{guile.m4} is not part of the project,
3651 it will not be distributed. Technically, that means a user who
3652 needs to rebuild @file{aclocal.m4} will have to install Guile first.
3653 This is probably OK, if Guile already is a requirement to build the
3654 package. However, if Guile is only an optional feature, or if your
3655 package might run on architectures where Guile cannot be installed,
3656 this requirement will hinder development. An easy solution is to copy
3657 such third-party macros in your local @file{m4/} directory so they get
3660 Since Automake 1.10, @command{aclocal} offers an option to copy these
3661 system-wide third-party macros in your local macro directory, solving
3662 the above problem. Simply use:
3665 ACLOCAL_AMFLAGS = -I m4 --install
3669 With this setup, system-wide macros will be copied to @file{m4/}
3670 the first time you run @command{autoreconf}. Then the locally
3671 installed macros will have precedence over the system-wide installed
3672 macros each time @command{aclocal} is run again.
3674 One reason why you should keep @option{--install} in the flags even
3675 after the first run is that when you later edit @file{configure.ac}
3676 and depend on a new macro, this macro will be installed in your
3677 @file{m4/} automatically. Another one is that serial numbers
3678 (@pxref{Serials}) can be used to update the macros in your source tree
3679 automatically when new system-wide versions are installed. A serial
3680 number should be a single line of the form
3687 where @var{nnn} contains only digits and dots. It should appear in
3688 the M4 file before any macro definition. It is a good practice to
3689 maintain a serial number for each macro you distribute, even if you do
3690 not use the @option{--install} option of @command{aclocal}: this allows
3691 other people to use it.
3695 @subsection Serial Numbers
3696 @cindex serial numbers in macros
3697 @cindex macro serial numbers
3698 @cindex @code{#serial} syntax
3699 @cindex @command{aclocal} and serial numbers
3701 Because third-party macros defined in @file{*.m4} files are naturally
3702 shared between multiple projects, some people like to version them.
3703 This makes it easier to tell which of two M4 files is newer. Since at
3704 least 1996, the tradition is to use a @samp{#serial} line for this.
3706 A serial number should be a single line of the form
3709 # serial @var{version}
3713 where @var{version} is a version number containing only digits and
3714 dots. Usually people use a single integer, and they increment it each
3715 time they change the macro (hence the name of ``serial''). Such a
3716 line should appear in the M4 file before any macro definition.
3718 The @samp{#} must be the first character on the line,
3719 and it is OK to have extra words after the version, as in
3722 #serial @var{version} @var{garbage}
3725 Normally these serial numbers are completely ignored by
3726 @command{aclocal} and @command{autoconf}, like any genuine comment.
3727 However when using @command{aclocal}'s @option{--install} feature, these
3728 serial numbers will modify the way @command{aclocal} selects the
3729 macros to install in the package: if two files with the same basename
3730 exist in your search path, and if at least one of them uses a
3731 @samp{#serial} line, @command{aclocal} will ignore the file that has
3732 the older @samp{#serial} line (or the file that has none).
3734 Note that a serial number applies to a whole M4 file, not to any macro
3735 it contains. A file can contains multiple macros, but only one
3738 Here is a use case that illustrates the use of @option{--install} and
3739 its interaction with serial numbers. Let's assume we maintain a
3740 package called MyPackage, the @file{configure.ac} of which requires a
3741 third-party macro @code{AX_THIRD_PARTY} defined in
3742 @file{/usr/share/aclocal/thirdparty.m4} as follows:
3746 AC_DEFUN([AX_THIRD_PARTY], [...])
3749 MyPackage uses an @file{m4/} directory to store local macros as
3750 explained in @ref{Local Macros}, and has
3753 ACLOCAL_AMFLAGS = -I m4 --install
3757 in its top-level @file{Makefile.am}.
3759 Initially the @file{m4/} directory is empty. The first time we run
3760 @command{autoreconf}, it will fetch the options to pass to
3761 @command{aclocal} in @file{Makefile.am}, and run @samp{aclocal -I m4
3762 --install}. @command{aclocal} will notice that
3766 @file{configure.ac} uses @code{AX_THIRD_PARTY}
3768 No local macros define @code{AX_THIRD_PARTY}
3770 @file{/usr/share/aclocal/thirdparty.m4} defines @code{AX_THIRD_PARTY}
3775 Because @file{/usr/share/aclocal/thirdparty.m4} is a system-wide macro
3776 and @command{aclocal} was given the @option{--install} option, it will
3777 copy this file in @file{m4/thirdparty.m4}, and output an
3778 @file{aclocal.m4} that contains @samp{m4_include([m4/thirdparty.m4])}.
3780 The next time @samp{aclocal -I m4 --install} is run (either via
3781 @command{autoreconf}, by hand, or from the @file{Makefile} rebuild
3782 rules) something different happens. @command{aclocal} notices that
3786 @file{configure.ac} uses @code{AX_THIRD_PARTY}
3788 @file{m4/thirdparty.m4} defines @code{AX_THIRD_PARTY}
3791 @file{/usr/share/aclocal/thirdparty.m4} defines @code{AX_THIRD_PARTY}
3796 Because both files have the same serial number, @command{aclocal} uses
3797 the first it found in its search path order (@pxref{Macro Search
3798 Path}). @command{aclocal} therefore ignores
3799 @file{/usr/share/aclocal/thirdparty.m4} and outputs an
3800 @file{aclocal.m4} that contains @samp{m4_include([m4/thirdparty.m4])}.
3802 Local directories specified with @option{-I} are always searched before
3803 system-wide directories, so a local file will always be preferred to
3804 the system-wide file in case of equal serial numbers.
3806 Now suppose the system-wide third-party macro is changed. This can
3807 happen if the package installing this macro is updated. Let's suppose
3808 the new macro has serial number 2. The next time @samp{aclocal -I m4
3809 --install} is run the situation is the following:
3813 @file{configure.ac} uses @code{AX_THIRD_PARTY}
3815 @file{m4/thirdparty.m4} defines @code{AX_THIRD_PARTY}
3818 @file{/usr/share/aclocal/thirdparty.m4} defines @code{AX_THIRD_PARTY}
3823 When @command{aclocal} sees a greater serial number, it immediately
3824 forgets anything it knows from files that have the same basename and a
3825 smaller serial number. So after it has found
3826 @file{/usr/share/aclocal/thirdparty.m4} with serial 2,
3827 @command{aclocal} will proceed as if it had never seen
3828 @file{m4/thirdparty.m4}. This brings us back to a situation similar
3829 to that at the beginning of our example, where no local file defined
3830 the macro. @command{aclocal} will install the new version of the
3831 macro in @file{m4/thirdparty.m4}, in this case overriding the old
3832 version. MyPackage just had its macro updated as a side effect of
3833 running @command{aclocal}.
3835 If you are leery of letting @command{aclocal} update your local macro,
3836 you can run @samp{aclocal -I m4 --diff} to review the changes
3837 @samp{aclocal -I m4 --install} would perform on these macros.
3839 Finally, note that the @option{--force} option of @command{aclocal} has
3840 absolutely no effect on the files installed by @option{--install}. For
3841 instance, if you have modified your local macros, do not expect
3842 @option{--install --force} to replace the local macros by their
3843 system-wide versions. If you want to do so, simply erase the local
3844 macros you want to revert, and run @samp{aclocal -I m4 --install}.
3847 @node Future of aclocal
3848 @subsection The Future of @command{aclocal}
3849 @cindex @command{aclocal}'s scheduled death
3851 @command{aclocal} is expected to disappear. This feature really
3852 should not be offered by Automake. Automake should focus on
3853 generating @file{Makefile}s; dealing with M4 macros really is
3854 Autoconf's job. The fact that some people install Automake just to use
3855 @command{aclocal}, but do not use @command{automake} otherwise is an
3856 indication of how that feature is misplaced.
3858 The new implementation will probably be done slightly differently.
3859 For instance, it could enforce the @file{m4/}-style layout discussed in
3862 We have no idea when and how this will happen. This has been
3863 discussed several times in the past, but someone still has to commit
3864 to that non-trivial task.
3866 From the user point of view, @command{aclocal}'s removal might turn
3867 out to be painful. There is a simple precaution that you may take to
3868 make that switch more seamless: never call @command{aclocal} yourself.
3869 Keep this guy under the exclusive control of @command{autoreconf} and
3870 Automake's rebuild rules. Hopefully you won't need to worry about
3871 things breaking, when @command{aclocal} disappears, because everything
3872 will have been taken care of. If otherwise you used to call
3873 @command{aclocal} directly yourself or from some script, you will
3874 quickly notice the change.
3876 Many packages come with a script called @file{bootstrap.sh} or
3877 @file{autogen.sh}, that will just call @command{aclocal},
3878 @command{libtoolize}, @command{gettextize} or @command{autopoint},
3879 @command{autoconf}, @command{autoheader}, and @command{automake} in
3880 the right order. Actually this is precisely what @command{autoreconf}
3881 can do for you. If your package has such a @file{bootstrap.sh} or
3882 @file{autogen.sh} script, consider using @command{autoreconf}. That
3883 should simplify its logic a lot (less things to maintain, yum!), it's
3884 even likely you will not need the script anymore, and more to the point
3885 you will not call @command{aclocal} directly anymore.
3887 For the time being, third-party packages should continue to install
3888 public macros into @file{/usr/share/aclocal/}. If @command{aclocal}
3889 is replaced by another tool it might make sense to rename the
3890 directory, but supporting @file{/usr/share/aclocal/} for backward
3891 compatibility should be really easy provided all macros are properly
3892 written (@pxref{Extending aclocal}).
3897 @section Autoconf macros supplied with Automake
3899 Automake ships with several Autoconf macros that you can use from your
3900 @file{configure.ac}. When you use one of them it will be included by
3901 @command{aclocal} in @file{aclocal.m4}.
3904 * Public Macros:: Macros that you can use.
3905 * Obsolete Macros:: Macros that you should stop using.
3906 * Private Macros:: Macros that you should not use.
3909 @c consider generating the following subsections automatically from m4 files.
3912 @subsection Public Macros
3916 @item AM_ENABLE_MULTILIB
3917 @acindex AM_ENABLE_MULTILIB
3918 This is used when a ``multilib'' library is being built. The first
3919 optional argument is the name of the @file{Makefile} being generated; it
3920 defaults to @samp{Makefile}. The second optional argument is used to find
3921 the top source directory; it defaults to the empty string (generally
3922 this should not be used unless you are familiar with the internals).
3925 @item AM_INIT_AUTOMAKE([OPTIONS])
3926 @itemx AM_INIT_AUTOMAKE(PACKAGE, VERSION, [NO-DEFINE])
3927 @acindex AM_INIT_AUTOMAKE
3928 Runs many macros required for proper operation of the generated Makefiles.
3930 @vindex AUTOMAKE_OPTIONS
3931 This macro has two forms, the first of which is preferred.
3932 In this form, @code{AM_INIT_AUTOMAKE} is called with a
3933 single argument: a space-separated list of Automake options that should
3934 be applied to every @file{Makefile.am} in the tree. The effect is as if
3935 each option were listed in @code{AUTOMAKE_OPTIONS} (@pxref{Options}).
3938 The second, deprecated, form of @code{AM_INIT_AUTOMAKE} has two required
3939 arguments: the package and the version number. This form is
3940 obsolete because the @var{package} and @var{version} can be obtained
3941 from Autoconf's @code{AC_INIT} macro (which itself has an old and a new
3944 If your @file{configure.ac} has:
3947 AC_INIT([src/foo.c])
3948 AM_INIT_AUTOMAKE([mumble], [1.5])
3952 you can modernize it as follows:
3955 AC_INIT([mumble], [1.5])
3956 AC_CONFIG_SRCDIR([src/foo.c])
3960 Note that if you're upgrading your @file{configure.ac} from an earlier
3961 version of Automake, it is not always correct to simply move the
3962 package and version arguments from @code{AM_INIT_AUTOMAKE} directly to
3963 @code{AC_INIT}, as in the example above. The first argument to
3964 @code{AC_INIT} should be the name of your package (e.g., @samp{GNU
3965 Automake}), not the tarball name (e.g., @samp{automake}) that you used
3966 to pass to @code{AM_INIT_AUTOMAKE}. Autoconf tries to derive a
3967 tarball name from the package name, which should work for most but not
3968 all package names. (If it doesn't work for yours, you can use the
3969 four-argument form of @code{AC_INIT} to provide the tarball name
3972 @cindex @code{PACKAGE}, prevent definition
3973 @cindex @code{VERSION}, prevent definition
3975 By default this macro @code{AC_DEFINE}'s @code{PACKAGE} and
3976 @code{VERSION}. This can be avoided by passing the @option{no-define}
3979 AM_INIT_AUTOMAKE([gnits 1.5 no-define dist-bzip2])
3981 or by passing a third non-empty argument to the obsolete form.
3983 @item AM_PATH_LISPDIR
3984 @acindex AM_PATH_LISPDIR
3987 Searches for the program @command{emacs}, and, if found, sets the
3988 output variable @code{lispdir} to the full path to Emacs' site-lisp
3991 Note that this test assumes the @command{emacs} found to be a version
3992 that supports Emacs Lisp (such as GNU Emacs or XEmacs). Other
3993 emacsen can cause this test to hang (some, like old versions of
3994 MicroEmacs, start up in interactive mode, requiring @kbd{C-x C-c} to
3995 exit, which is hardly obvious for a non-emacs user). In most cases,
3996 however, you should be able to use @kbd{C-c} to kill the test. In
3997 order to avoid problems, you can set @env{EMACS} to ``no'' in the
3998 environment, or use the @option{--with-lispdir} option to
3999 @command{configure} to explicitly set the correct path (if you're sure
4000 you have an @command{emacs} that supports Emacs Lisp).
4002 @item AM_PROG_AR(@ovar{act-if-fail})
4005 You must use this macro when you use the archiver in your project, if
4006 you want support for unusual archivers such as Microsoft @command{lib}.
4007 The content of the optional argument is executed if the archiver
4008 interface is not recognized; the default action is to abort configure
4009 with an error message.
4015 Use this macro when you have assembly code in your project. This will
4016 choose the assembler for you (by default the C compiler) and set
4017 @code{CCAS}, and will also set @code{CCASFLAGS} if required.
4019 @item AM_PROG_CC_C_O
4020 @acindex AM_PROG_CC_C_O
4021 @acindex AC_PROG_CC_C_O
4022 This is like @code{AC_PROG_CC_C_O}, but it generates its results in
4023 the manner required by Automake. You must use this instead of
4024 @code{AC_PROG_CC_C_O} when you need this functionality, that is, when
4025 using per-target flags or subdir-objects with C sources.
4028 @acindex AM_PROG_LEX
4029 @acindex AC_PROG_LEX
4030 @cindex HP-UX 10, @command{lex} problems
4031 @cindex @command{lex} problems with HP-UX 10
4032 Like @code{AC_PROG_LEX} (@pxref{Particular Programs, , Particular
4033 Program Checks, autoconf, The Autoconf Manual}), but uses the
4034 @command{missing} script on systems that do not have @command{lex}.
4035 HP-UX 10 is one such system.
4038 @acindex AM_PROG_GCJ
4041 This macro finds the @command{gcj} program or causes an error. It sets
4042 @code{GCJ} and @code{GCJFLAGS}. @command{gcj} is the Java front-end to the
4043 GNU Compiler Collection.
4045 @item AM_PROG_UPC([@var{compiler-search-list}])
4046 @acindex AM_PROG_UPC
4048 Find a compiler for Unified Parallel C and define the @code{UPC}
4049 variable. The default @var{compiler-search-list} is @samp{upcc upc}.
4050 This macro will abort @command{configure} if no Unified Parallel C
4053 @item AM_SILENT_RULES
4054 @acindex AM_SILENT_RULES
4055 Enable the machinery for less verbose build output (@pxref{Options}).
4057 @item AM_WITH_DMALLOC
4058 @acindex AM_WITH_DMALLOC
4059 @cindex @command{dmalloc}, support for
4060 @vindex WITH_DMALLOC
4061 @opindex --with-dmalloc
4062 Add support for the @uref{http://dmalloc.com/, Dmalloc package}. If
4063 the user runs @command{configure} with @option{--with-dmalloc}, then
4064 define @code{WITH_DMALLOC} and add @option{-ldmalloc} to @code{LIBS}.
4067 @acindex AM_WITH_REGEX
4069 @opindex --with-regex
4070 @cindex regex package
4072 Adds @option{--with-regex} to the @command{configure} command line. If
4073 specified (the default), then the @samp{regex} regular expression
4074 library is used, @file{regex.o} is put into @code{LIBOBJS}, and
4075 @code{WITH_REGEX} is defined. If @option{--without-regex} is given, then
4076 the @code{rx} regular expression library is used, and @file{rx.o} is put
4077 into @code{LIBOBJS}.
4082 @node Obsolete Macros
4083 @subsection Obsolete Macros
4084 @cindex obsolete macros
4087 Although using some of the following macros was required in past
4088 releases, you should not use any of them in new code. Running
4089 @command{autoupdate} should adjust your @file{configure.ac}
4090 automatically (@pxref{autoupdate Invocation, , Using
4091 @command{autoupdate} to Modernize @file{configure.ac}, autoconf, The
4095 @item AM_C_PROTOTYPES
4096 @acindex AM_C_PROTOTYPES
4099 Check to see if function prototypes are understood by the compiler. If
4100 so, define @samp{PROTOTYPES} and set the output variables @code{U} and
4101 @code{ANSI2KNR} to the empty string. Otherwise, set @code{U} to
4102 @samp{_} and @code{ANSI2KNR} to @samp{./ansi2knr}. Automake used these
4103 values to implement the deprecated de-ANSI-fication feature; however,
4104 support for @emph{that feature will be removed} in the next major Automake
4105 release, and then @emph{these macros and variables will go away as well}.
4107 @item AM_CONFIG_HEADER
4108 @acindex AM_CONFIG_HEADER
4109 Automake will generate rules to automatically regenerate the config
4110 header. This obsolete macro is a synonym of @code{AC_CONFIG_HEADERS}
4111 today (@pxref{Optional}).
4113 @item AM_HEADER_TIOCGWINSZ_NEEDS_SYS_IOCTL
4114 @acindex AM_HEADER_TIOCGWINSZ_NEEDS_SYS_IOCTL
4115 If the use of @code{TIOCGWINSZ} requires @file{<sys/ioctl.h>}, then
4116 define @code{GWINSZ_IN_SYS_IOCTL}. Otherwise @code{TIOCGWINSZ} can be
4117 found in @file{<termios.h>}. This macro is obsolete, you should
4118 use Autoconf's @code{AC_HEADER_TIOCGWINSZ} instead.
4120 @item AM_PROG_MKDIR_P
4121 @acindex AM_PROG_MKDIR_P
4122 @cindex @code{mkdir -p}, macro check
4126 From Automake 1.8 to 1.9.6 this macro used to define the output
4127 variable @code{mkdir_p} to one of @code{mkdir -p}, @code{install-sh
4128 -d}, or @code{mkinstalldirs}.
4130 Nowadays Autoconf provides a similar functionality with
4131 @code{AC_PROG_MKDIR_P} (@pxref{Particular Programs, , Particular
4132 Program Checks, autoconf, The Autoconf Manual}), however this defines
4133 the output variable @code{MKDIR_P} instead. Therefore
4134 @code{AM_PROG_MKDIR_P} has been rewritten as a thin wrapper around
4135 @code{AC_PROG_MKDIR_P} to define @code{mkdir_p} to the same value as
4136 @code{MKDIR_P} for backward compatibility.
4138 If you are using Automake, there is normally no reason to call this
4139 macro, because @code{AM_INIT_AUTOMAKE} already does so. However, make
4140 sure that the custom rules in your @file{Makefile}s use
4141 @code{$(MKDIR_P)} and not @code{$(mkdir_p)}. Even if both variables
4142 still work, the latter should be considered obsolete.
4144 If you are not using Automake, please call @code{AC_PROG_MKDIR_P}
4145 instead of @code{AM_PROG_MKDIR_P}.
4147 @item AM_SYS_POSIX_TERMIOS
4148 @acindex AM_SYS_POSIX_TERMIOS
4149 @cindex POSIX termios headers
4150 @cindex termios POSIX headers
4151 Check to see if POSIX termios headers and functions are available on the
4152 system. If so, set the shell variable @code{am_cv_sys_posix_termios} to
4153 @samp{yes}. If not, set the variable to @samp{no}. This macro is obsolete,
4154 you should use Autoconf's @code{AC_SYS_POSIX_TERMIOS} instead.
4159 @node Private Macros
4160 @subsection Private Macros
4162 The following macros are private macros you should not call directly.
4163 They are called by the other public macros when appropriate. Do not
4164 rely on them, as they might be changed in a future version. Consider
4165 them as implementation details; or better, do not consider them at all:
4169 @item _AM_DEPENDENCIES
4170 @itemx AM_SET_DEPDIR
4172 @itemx AM_OUTPUT_DEPENDENCY_COMMANDS
4173 These macros are used to implement Automake's automatic dependency
4174 tracking scheme. They are called automatically by Automake when
4175 required, and there should be no need to invoke them manually.
4177 @item AM_MAKE_INCLUDE
4178 This macro is used to discover how the user's @command{make} handles
4179 @code{include} statements. This macro is automatically invoked when
4180 needed; there should be no need to invoke it manually.
4182 @item AM_PROG_INSTALL_STRIP
4183 This is used to find a version of @code{install} that can be used to
4184 strip a program at installation time. This macro is automatically
4185 included when required.
4187 @item AM_SANITY_CHECK
4188 This checks to make sure that a file created in the build directory is
4189 newer than a file in the source directory. This can fail on systems
4190 where the clock is set incorrectly. This macro is automatically run
4191 from @code{AM_INIT_AUTOMAKE}.
4197 @chapter Directories
4199 For simple projects that distribute all files in the same directory
4200 it is enough to have a single @file{Makefile.am} that builds
4201 everything in place.
4203 In larger projects it is common to organize files in different
4204 directories, in a tree. For instance one directory per program, per
4205 library or per module. The traditional approach is to build these
4206 subdirectories recursively: each directory contains its @file{Makefile}
4207 (generated from @file{Makefile.am}), and when @command{make} is run
4208 from the top level directory it enters each subdirectory in turn to
4212 * Subdirectories:: Building subdirectories recursively
4213 * Conditional Subdirectories:: Conditionally not building directories
4214 * Alternative:: Subdirectories without recursion
4215 * Subpackages:: Nesting packages
4218 @node Subdirectories
4219 @section Recursing subdirectories
4221 @cindex @code{SUBDIRS}, explained
4223 In packages with subdirectories, the top level @file{Makefile.am} must
4224 tell Automake which subdirectories are to be built. This is done via
4225 the @code{SUBDIRS} variable.
4228 The @code{SUBDIRS} variable holds a list of subdirectories in which
4229 building of various sorts can occur. The rules for many targets
4230 (e.g., @code{all}) in the generated @file{Makefile} will run commands
4231 both locally and in all specified subdirectories. Note that the
4232 directories listed in @code{SUBDIRS} are not required to contain
4233 @file{Makefile.am}s; only @file{Makefile}s (after configuration).
4234 This allows inclusion of libraries from packages that do not use
4235 Automake (such as @code{gettext}; see also @ref{Third-Party
4238 In packages that use subdirectories, the top-level @file{Makefile.am} is
4239 often very short. For instance, here is the @file{Makefile.am} from the
4240 GNU Hello distribution:
4243 EXTRA_DIST = BUGS ChangeLog.O README-alpha
4244 SUBDIRS = doc intl po src tests
4247 When Automake invokes @command{make} in a subdirectory, it uses the value
4248 of the @code{MAKE} variable. It passes the value of the variable
4249 @code{AM_MAKEFLAGS} to the @command{make} invocation; this can be set in
4250 @file{Makefile.am} if there are flags you must always pass to
4253 @vindex AM_MAKEFLAGS
4255 The directories mentioned in @code{SUBDIRS} are usually direct
4256 children of the current directory, each subdirectory containing its
4257 own @file{Makefile.am} with a @code{SUBDIRS} pointing to deeper
4258 subdirectories. Automake can be used to construct packages of
4259 arbitrary depth this way.
4261 By default, Automake generates @file{Makefiles} that work depth-first
4262 in postfix order: the subdirectories are built before the current
4263 directory. However, it is possible to change this ordering. You can
4264 do this by putting @samp{.} into @code{SUBDIRS}. For instance,
4265 putting @samp{.} first will cause a prefix ordering of
4271 SUBDIRS = lib src . test
4275 will cause @file{lib/} to be built before @file{src/}, then the
4276 current directory will be built, finally the @file{test/} directory
4277 will be built. It is customary to arrange test directories to be
4278 built after everything else since they are meant to test what has
4281 All @code{clean} rules are run in reverse order of build rules.
4283 @node Conditional Subdirectories
4284 @section Conditional Subdirectories
4285 @cindex Subdirectories, building conditionally
4286 @cindex Conditional subdirectories
4287 @cindex @code{SUBDIRS}, conditional
4288 @cindex Conditional @code{SUBDIRS}
4290 It is possible to define the @code{SUBDIRS} variable conditionally if,
4291 like in the case of GNU Inetutils, you want to only build a subset of
4294 To illustrate how this works, let's assume we have two directories
4295 @file{src/} and @file{opt/}. @file{src/} should always be built, but we
4296 want to decide in @command{configure} whether @file{opt/} will be built
4297 or not. (For this example we will assume that @file{opt/} should be
4298 built when the variable @samp{$want_opt} was set to @samp{yes}.)
4300 Running @command{make} should thus recurse into @file{src/} always, and
4301 then maybe in @file{opt/}.
4303 However @samp{make dist} should always recurse into both @file{src/}
4304 and @file{opt/}. Because @file{opt/} should be distributed even if it
4305 is not needed in the current configuration. This means
4306 @file{opt/Makefile} should be created @emph{unconditionally}.
4308 There are two ways to setup a project like this. You can use Automake
4309 conditionals (@pxref{Conditionals}) or use Autoconf @code{AC_SUBST}
4310 variables (@pxref{Setting Output Variables, , Setting Output
4311 Variables, autoconf, The Autoconf Manual}). Using Automake
4312 conditionals is the preferred solution. Before we illustrate these
4313 two possibilities, let's introduce @code{DIST_SUBDIRS}.
4316 * SUBDIRS vs DIST_SUBDIRS:: Two sets of directories
4317 * Subdirectories with AM_CONDITIONAL:: Specifying conditional subdirectories
4318 * Subdirectories with AC_SUBST:: Another way for conditional recursion
4319 * Unconfigured Subdirectories:: Not even creating a @samp{Makefile}
4322 @node SUBDIRS vs DIST_SUBDIRS
4323 @subsection @code{SUBDIRS} vs.@: @code{DIST_SUBDIRS}
4324 @cindex @code{DIST_SUBDIRS}, explained
4326 Automake considers two sets of directories, defined by the variables
4327 @code{SUBDIRS} and @code{DIST_SUBDIRS}.
4329 @code{SUBDIRS} contains the subdirectories of the current directory
4330 that must be built (@pxref{Subdirectories}). It must be defined
4331 manually; Automake will never guess a directory is to be built. As we
4332 will see in the next two sections, it is possible to define it
4333 conditionally so that some directory will be omitted from the build.
4335 @code{DIST_SUBDIRS} is used in rules that need to recurse in all
4336 directories, even those that have been conditionally left out of the
4337 build. Recall our example where we may not want to build subdirectory
4338 @file{opt/}, but yet we want to distribute it? This is where
4339 @code{DIST_SUBDIRS} comes into play: @samp{opt} may not appear in
4340 @code{SUBDIRS}, but it must appear in @code{DIST_SUBDIRS}.
4342 Precisely, @code{DIST_SUBDIRS} is used by @samp{make
4343 maintainer-clean}, @samp{make distclean} and @samp{make dist}. All
4344 other recursive rules use @code{SUBDIRS}.
4346 If @code{SUBDIRS} is defined conditionally using Automake
4347 conditionals, Automake will define @code{DIST_SUBDIRS} automatically
4348 from the possible values of @code{SUBDIRS} in all conditions.
4350 If @code{SUBDIRS} contains @code{AC_SUBST} variables,
4351 @code{DIST_SUBDIRS} will not be defined correctly because Automake
4352 does not know the possible values of these variables. In this case
4353 @code{DIST_SUBDIRS} needs to be defined manually.
4355 @node Subdirectories with AM_CONDITIONAL
4356 @subsection Subdirectories with @code{AM_CONDITIONAL}
4357 @cindex @code{SUBDIRS} and @code{AM_CONDITIONAL}
4358 @cindex @code{AM_CONDITIONAL} and @code{SUBDIRS}
4360 @c Keep in sync with subcond2.test.
4362 @file{configure} should output the @file{Makefile} for each directory
4363 and define a condition into which @file{opt/} should be built.
4367 AM_CONDITIONAL([COND_OPT], [test "$want_opt" = yes])
4368 AC_CONFIG_FILES([Makefile src/Makefile opt/Makefile])
4372 Then @code{SUBDIRS} can be defined in the top-level @file{Makefile.am}
4379 SUBDIRS = src $(MAYBE_OPT)
4382 As you can see, running @command{make} will rightly recurse into
4383 @file{src/} and maybe @file{opt/}.
4385 @vindex DIST_SUBDIRS
4386 As you can't see, running @samp{make dist} will recurse into both
4387 @file{src/} and @file{opt/} directories because @samp{make dist}, unlike
4388 @samp{make all}, doesn't use the @code{SUBDIRS} variable. It uses the
4389 @code{DIST_SUBDIRS} variable.
4391 In this case Automake will define @samp{DIST_SUBDIRS = src opt}
4392 automatically because it knows that @code{MAYBE_OPT} can contain
4393 @samp{opt} in some condition.
4395 @node Subdirectories with AC_SUBST
4396 @subsection Subdirectories with @code{AC_SUBST}
4397 @cindex @code{SUBDIRS} and @code{AC_SUBST}
4398 @cindex @code{AC_SUBST} and @code{SUBDIRS}
4400 @c Keep in sync with subcond3.test.
4402 Another possibility is to define @code{MAYBE_OPT} from
4403 @file{./configure} using @code{AC_SUBST}:
4407 if test "$want_opt" = yes; then
4412 AC_SUBST([MAYBE_OPT])
4413 AC_CONFIG_FILES([Makefile src/Makefile opt/Makefile])
4417 In this case the top-level @file{Makefile.am} should look as follows.
4420 SUBDIRS = src $(MAYBE_OPT)
4421 DIST_SUBDIRS = src opt
4424 The drawback is that since Automake cannot guess what the possible
4425 values of @code{MAYBE_OPT} are, it is necessary to define
4426 @code{DIST_SUBDIRS}.
4428 @node Unconfigured Subdirectories
4429 @subsection Unconfigured Subdirectories
4430 @cindex Subdirectories, configured conditionally
4432 The semantics of @code{DIST_SUBDIRS} are often misunderstood by some
4433 users that try to @emph{configure and build} subdirectories
4434 conditionally. Here by configuring we mean creating the
4435 @file{Makefile} (it might also involve running a nested
4436 @command{configure} script: this is a costly operation that explains
4437 why people want to do it conditionally, but only the @file{Makefile}
4438 is relevant to the discussion).
4440 The above examples all assume that every @file{Makefile} is created,
4441 even in directories that are not going to be built. The simple reason
4442 is that we want @samp{make dist} to distribute even the directories
4443 that are not being built (e.g., platform-dependent code), hence
4444 @file{make dist} must recurse into the subdirectory, hence this
4445 directory must be configured and appear in @code{DIST_SUBDIRS}.
4447 Building packages that do not configure every subdirectory is a tricky
4448 business, and we do not recommend it to the novice as it is easy to
4449 produce an incomplete tarball by mistake. We will not discuss this
4450 topic in depth here, yet for the adventurous here are a few rules to
4455 @item @code{SUBDIRS} should always be a subset of @code{DIST_SUBDIRS}.
4457 It makes little sense to have a directory in @code{SUBDIRS} that
4458 is not in @code{DIST_SUBDIRS}. Think of the former as a way to tell
4459 which directories listed in the latter should be built.
4460 @item Any directory listed in @code{DIST_SUBDIRS} and @code{SUBDIRS}
4463 I.e., the @file{Makefile} must exists or the recursive @command{make}
4464 rules will not be able to process the directory.
4465 @item Any configured directory must be listed in @code{DIST_SUBDIRS}.
4467 So that the cleaning rules remove the generated @file{Makefile}s.
4468 It would be correct to see @code{DIST_SUBDIRS} as a variable that
4469 lists all the directories that have been configured.
4473 In order to prevent recursion in some unconfigured directory you
4474 must therefore ensure that this directory does not appear in
4475 @code{DIST_SUBDIRS} (and @code{SUBDIRS}). For instance, if you define
4476 @code{SUBDIRS} conditionally using @code{AC_SUBST} and do not define
4477 @code{DIST_SUBDIRS} explicitly, it will be default to
4478 @samp{$(SUBDIRS)}; another possibility is to force @code{DIST_SUBDIRS
4481 Of course, directories that are omitted from @code{DIST_SUBDIRS} will
4482 not be distributed unless you make other arrangements for this to
4483 happen (for instance, always running @samp{make dist} in a
4484 configuration where all directories are known to appear in
4485 @code{DIST_SUBDIRS}; or writing a @code{dist-hook} target to
4486 distribute these directories).
4488 @cindex Subdirectories, not distributed
4489 In few packages, unconfigured directories are not even expected to
4490 be distributed. Although these packages do not require the
4491 aforementioned extra arrangements, there is another pitfall. If the
4492 name of a directory appears in @code{SUBDIRS} or @code{DIST_SUBDIRS},
4493 @command{automake} will make sure the directory exists. Consequently
4494 @command{automake} cannot be run on such a distribution when one
4495 directory has been omitted. One way to avoid this check is to use the
4496 @code{AC_SUBST} method to declare conditional directories; since
4497 @command{automake} does not know the values of @code{AC_SUBST}
4498 variables it cannot ensure the corresponding directory exists.
4501 @section An Alternative Approach to Subdirectories
4503 If you've ever read Peter Miller's excellent paper,
4504 @uref{http://miller.emu.id.au/pmiller/books/rmch/,
4505 Recursive Make Considered Harmful}, the preceding sections on the use of
4506 subdirectories will probably come as unwelcome advice. For those who
4507 haven't read the paper, Miller's main thesis is that recursive
4508 @command{make} invocations are both slow and error-prone.
4510 Automake provides sufficient cross-directory support @footnote{We
4511 believe. This work is new and there are probably warts.
4512 @xref{Introduction}, for information on reporting bugs.} to enable you
4513 to write a single @file{Makefile.am} for a complex multi-directory
4517 By default an installable file specified in a subdirectory will have its
4518 directory name stripped before installation. For instance, in this
4519 example, the header file will be installed as
4520 @file{$(includedir)/stdio.h}:
4523 include_HEADERS = inc/stdio.h
4527 @cindex @code{nobase_} prefix
4528 @cindex Path stripping, avoiding
4529 @cindex Avoiding path stripping
4531 However, the @samp{nobase_} prefix can be used to circumvent this path
4532 stripping. In this example, the header file will be installed as
4533 @file{$(includedir)/sys/types.h}:
4536 nobase_include_HEADERS = sys/types.h
4539 @cindex @code{nobase_} and @code{dist_} or @code{nodist_}
4540 @cindex @code{dist_} and @code{nobase_}
4541 @cindex @code{nodist_} and @code{nobase_}
4545 @samp{nobase_} should be specified first when used in conjunction with
4546 either @samp{dist_} or @samp{nodist_} (@pxref{Fine-grained Distribution
4547 Control}). For instance:
4550 nobase_dist_pkgdata_DATA = images/vortex.pgm sounds/whirl.ogg
4553 Finally, note that a variable using the @samp{nobase_} prefix can
4554 often be replaced by several variables, one for each destination
4555 directory (@pxref{Uniform}). For instance, the last example could be
4556 rewritten as follows:
4558 @c Keep in sync with primary-prefix-couples-documented-valid.test.
4560 imagesdir = $(pkgdatadir)/images
4561 soundsdir = $(pkgdatadir)/sounds
4562 dist_images_DATA = images/vortex.pgm
4563 dist_sounds_DATA = sounds/whirl.ogg
4567 This latter syntax makes it possible to change one destination
4568 directory without changing the layout of the source tree.
4570 Currently, @samp{nobase_*_LTLIBRARIES} are the only exception to this
4571 rule, in that there is no particular installation order guarantee for
4572 an otherwise equivalent set of variables without @samp{nobase_} prefix.
4575 @section Nesting Packages
4576 @cindex Nesting packages
4578 @acindex AC_CONFIG_SUBDIRS
4579 @acindex AC_CONFIG_AUX_DIR
4582 In the GNU Build System, packages can be nested to arbitrary depth.
4583 This means that a package can embed other packages with their own
4584 @file{configure}, @file{Makefile}s, etc.
4586 These other packages should just appear as subdirectories of their
4587 parent package. They must be listed in @code{SUBDIRS} like other
4588 ordinary directories. However the subpackage's @file{Makefile}s
4589 should be output by its own @file{configure} script, not by the
4590 parent's @file{configure}. This is achieved using the
4591 @code{AC_CONFIG_SUBDIRS} Autoconf macro (@pxref{Subdirectories,
4592 AC_CONFIG_SUBDIRS, Configuring Other Packages in Subdirectories,
4593 autoconf, The Autoconf Manual}).
4595 Here is an example package for an @code{arm} program that links with
4596 a @code{hand} library that is a nested package in subdirectory
4599 @code{arm}'s @file{configure.ac}:
4602 AC_INIT([arm], [1.0])
4603 AC_CONFIG_AUX_DIR([.])
4606 AC_CONFIG_FILES([Makefile])
4607 # Call hand's ./configure script recursively.
4608 AC_CONFIG_SUBDIRS([hand])
4612 @code{arm}'s @file{Makefile.am}:
4615 # Build the library in the hand subdirectory first.
4618 # Include hand's header when compiling this directory.
4619 AM_CPPFLAGS = -I$(srcdir)/hand
4623 # link with the hand library.
4624 arm_LDADD = hand/libhand.a
4627 Now here is @code{hand}'s @file{hand/configure.ac}:
4630 AC_INIT([hand], [1.2])
4631 AC_CONFIG_AUX_DIR([.])
4636 AC_CONFIG_FILES([Makefile])
4641 and its @file{hand/Makefile.am}:
4644 lib_LIBRARIES = libhand.a
4645 libhand_a_SOURCES = hand.c
4648 When @samp{make dist} is run from the top-level directory it will
4649 create an archive @file{arm-1.0.tar.gz} that contains the @code{arm}
4650 code as well as the @file{hand} subdirectory. This package can be
4651 built and installed like any ordinary package, with the usual
4652 @samp{./configure && make && make install} sequence (the @code{hand}
4653 subpackage will be built and installed by the process).
4655 When @samp{make dist} is run from the hand directory, it will create a
4656 self-contained @file{hand-1.2.tar.gz} archive. So although it appears
4657 to be embedded in another package, it can still be used separately.
4659 The purpose of the @samp{AC_CONFIG_AUX_DIR([.])} instruction is to
4660 force Automake and Autoconf to search for auxiliary scripts in the
4661 current directory. For instance, this means that there will be two
4662 copies of @file{install-sh}: one in the top-level of the @code{arm}
4663 package, and another one in the @file{hand/} subdirectory for the
4664 @code{hand} package.
4666 The historical default is to search for these auxiliary scripts in
4667 the parent directory and the grandparent directory. So if the
4668 @samp{AC_CONFIG_AUX_DIR([.])} line was removed from
4669 @file{hand/configure.ac}, that subpackage would share the auxiliary
4670 script of the @code{arm} package. This may looks like a gain in size
4671 (a few kilobytes), but it is actually a loss of modularity as the
4672 @code{hand} subpackage is no longer self-contained (@samp{make dist}
4673 in the subdirectory will not work anymore).
4675 Packages that do not use Automake need more work to be integrated this
4676 way. @xref{Third-Party Makefiles}.
4679 @chapter Building Programs and Libraries
4681 A large part of Automake's functionality is dedicated to making it easy
4682 to build programs and libraries.
4685 * A Program:: Building a program
4686 * A Library:: Building a library
4687 * A Shared Library:: Building a Libtool library
4688 * Program and Library Variables:: Variables controlling program and
4690 * Default _SOURCES:: Default source files
4691 * LIBOBJS:: Special handling for LIBOBJS and ALLOCA
4692 * Program Variables:: Variables used when building a program
4693 * Yacc and Lex:: Yacc and Lex support
4694 * C++ Support:: Compiling C++ sources
4695 * Objective C Support:: Compiling Objective C sources
4696 * Unified Parallel C Support:: Compiling Unified Parallel C sources
4697 * Assembly Support:: Compiling assembly sources
4698 * Fortran 77 Support:: Compiling Fortran 77 sources
4699 * Fortran 9x Support:: Compiling Fortran 9x sources
4700 * Java Support with gcj:: Compiling Java sources using gcj
4701 * Vala Support:: Compiling Vala sources
4702 * Support for Other Languages:: Compiling other languages
4703 * ANSI:: Automatic de-ANSI-fication (deprecated, soon to be removed)
4704 * Dependencies:: Automatic dependency tracking
4705 * EXEEXT:: Support for executable extensions
4710 @section Building a program
4712 In order to build a program, you need to tell Automake which sources
4713 are part of it, and which libraries it should be linked with.
4715 This section also covers conditional compilation of sources or
4716 programs. Most of the comments about these also apply to libraries
4717 (@pxref{A Library}) and libtool libraries (@pxref{A Shared Library}).
4720 * Program Sources:: Defining program sources
4721 * Linking:: Linking with libraries or extra objects
4722 * Conditional Sources:: Handling conditional sources
4723 * Conditional Programs:: Building a program conditionally
4726 @node Program Sources
4727 @subsection Defining program sources
4729 @cindex @code{PROGRAMS}, @code{bindir}
4731 @vindex bin_PROGRAMS
4732 @vindex sbin_PROGRAMS
4733 @vindex libexec_PROGRAMS
4734 @vindex pkglibexec_PROGRAMS
4735 @vindex noinst_PROGRAMS
4736 @vindex check_PROGRAMS
4738 In a directory containing source that gets built into a program (as
4739 opposed to a library or a script), the @code{PROGRAMS} primary is used.
4740 Programs can be installed in @code{bindir}, @code{sbindir},
4741 @code{libexecdir}, @code{pkglibexecdir}, or not at all
4742 (@code{noinst_}). They can also be built only for @samp{make check}, in
4743 which case the prefix is @samp{check_}.
4748 bin_PROGRAMS = hello
4751 In this simple case, the resulting @file{Makefile.in} will contain code
4752 to generate a program named @code{hello}.
4754 Associated with each program are several assisting variables that are
4755 named after the program. These variables are all optional, and have
4756 reasonable defaults. Each variable, its use, and default is spelled out
4757 below; we use the ``hello'' example throughout.
4759 The variable @code{hello_SOURCES} is used to specify which source files
4760 get built into an executable:
4763 hello_SOURCES = hello.c version.c getopt.c getopt1.c getopt.h system.h
4766 This causes each mentioned @file{.c} file to be compiled into the
4767 corresponding @file{.o}. Then all are linked to produce @file{hello}.
4769 @cindex @code{_SOURCES} primary, defined
4770 @cindex @code{SOURCES} primary, defined
4771 @cindex Primary variable, @code{SOURCES}
4774 If @code{hello_SOURCES} is not specified, then it defaults to the single
4775 file @file{hello.c} (@pxref{Default _SOURCES}).
4779 Multiple programs can be built in a single directory. Multiple programs
4780 can share a single source file, which must be listed in each
4781 @code{_SOURCES} definition.
4783 @cindex Header files in @code{_SOURCES}
4784 @cindex @code{_SOURCES} and header files
4786 Header files listed in a @code{_SOURCES} definition will be included in
4787 the distribution but otherwise ignored. In case it isn't obvious, you
4788 should not include the header file generated by @file{configure} in a
4789 @code{_SOURCES} variable; this file should not be distributed. Lex
4790 (@file{.l}) and Yacc (@file{.y}) files can also be listed; see @ref{Yacc
4795 @subsection Linking the program
4797 If you need to link against libraries that are not found by
4798 @command{configure}, you can use @code{LDADD} to do so. This variable is
4799 used to specify additional objects or libraries to link with; it is
4800 inappropriate for specifying specific linker flags, you should use
4801 @code{AM_LDFLAGS} for this purpose.
4805 @cindex @code{prog_LDADD}, defined
4807 Sometimes, multiple programs are built in one directory but do not share
4808 the same link-time requirements. In this case, you can use the
4809 @code{@var{prog}_LDADD} variable (where @var{prog} is the name of the
4810 program as it appears in some @code{_PROGRAMS} variable, and usually
4811 written in lowercase) to override @code{LDADD}. If this variable exists
4812 for a given program, then that program is not linked using @code{LDADD}.
4815 For instance, in GNU cpio, @code{pax}, @code{cpio} and @code{mt} are
4816 linked against the library @file{libcpio.a}. However, @code{rmt} is
4817 built in the same directory, and has no such link requirement. Also,
4818 @code{mt} and @code{rmt} are only built on certain architectures. Here
4819 is what cpio's @file{src/Makefile.am} looks like (abridged):
4822 bin_PROGRAMS = cpio pax $(MT)
4823 libexec_PROGRAMS = $(RMT)
4824 EXTRA_PROGRAMS = mt rmt
4826 LDADD = ../lib/libcpio.a $(INTLLIBS)
4829 cpio_SOURCES = @dots{}
4830 pax_SOURCES = @dots{}
4831 mt_SOURCES = @dots{}
4832 rmt_SOURCES = @dots{}
4835 @cindex @code{_LDFLAGS}, defined
4836 @vindex maude_LDFLAGS
4837 @code{@var{prog}_LDADD} is inappropriate for passing program-specific
4838 linker flags (except for @option{-l}, @option{-L}, @option{-dlopen} and
4839 @option{-dlpreopen}). So, use the @code{@var{prog}_LDFLAGS} variable for
4842 @cindex @code{_DEPENDENCIES}, defined
4843 @vindex maude_DEPENDENCIES
4844 It is also occasionally useful to have a program depend on some other
4845 target that is not actually part of that program. This can be done
4846 using the @code{@var{prog}_DEPENDENCIES} variable. Each program
4847 depends on the contents of such a variable, but no further
4848 interpretation is done.
4850 Since these dependencies are associated to the link rule used to
4851 create the programs they should normally list files used by the link
4852 command. That is @file{*.$(OBJEXT)}, @file{*.a}, or @file{*.la}
4853 files. In rare cases you may need to add other kinds of files such as
4854 linker scripts, but @emph{listing a source file in
4855 @code{_DEPENDENCIES} is wrong}. If some source file needs to be built
4856 before all the components of a program are built, consider using the
4857 @code{BUILT_SOURCES} variable instead (@pxref{Sources}).
4859 If @code{@var{prog}_DEPENDENCIES} is not supplied, it is computed by
4860 Automake. The automatically-assigned value is the contents of
4861 @code{@var{prog}_LDADD}, with most configure substitutions, @option{-l},
4862 @option{-L}, @option{-dlopen} and @option{-dlpreopen} options removed. The
4863 configure substitutions that are left in are only @samp{$(LIBOBJS)} and
4864 @samp{$(ALLOCA)}; these are left because it is known that they will not
4865 cause an invalid value for @code{@var{prog}_DEPENDENCIES} to be
4868 @ref{Conditional Sources} shows a situation where @code{_DEPENDENCIES}
4871 @cindex @code{LDADD} and @option{-l}
4872 @cindex @option{-l} and @code{LDADD}
4873 We recommend that you avoid using @option{-l} options in @code{LDADD}
4874 or @code{@var{prog}_LDADD} when referring to libraries built by your
4875 package. Instead, write the file name of the library explicitly as in
4876 the above @code{cpio} example. Use @option{-l} only to list
4877 third-party libraries. If you follow this rule, the default value of
4878 @code{@var{prog}_DEPENDENCIES} will list all your local libraries and
4879 omit the other ones.
4882 @node Conditional Sources
4883 @subsection Conditional compilation of sources
4885 You can't put a configure substitution (e.g., @samp{@@FOO@@} or
4886 @samp{$(FOO)} where @code{FOO} is defined via @code{AC_SUBST}) into a
4887 @code{_SOURCES} variable. The reason for this is a bit hard to
4888 explain, but suffice to say that it simply won't work. Automake will
4889 give an error if you try to do this.
4891 Fortunately there are two other ways to achieve the same result. One is
4892 to use configure substitutions in @code{_LDADD} variables, the other is
4893 to use an Automake conditional.
4895 @subsubheading Conditional Compilation using @code{_LDADD} Substitutions
4897 @cindex @code{EXTRA_prog_SOURCES}, defined
4899 Automake must know all the source files that could possibly go into a
4900 program, even if not all the files are built in every circumstance. Any
4901 files that are only conditionally built should be listed in the
4902 appropriate @code{EXTRA_} variable. For instance, if
4903 @file{hello-linux.c} or @file{hello-generic.c} were conditionally included
4904 in @code{hello}, the @file{Makefile.am} would contain:
4907 bin_PROGRAMS = hello
4908 hello_SOURCES = hello-common.c
4909 EXTRA_hello_SOURCES = hello-linux.c hello-generic.c
4910 hello_LDADD = $(HELLO_SYSTEM)
4911 hello_DEPENDENCIES = $(HELLO_SYSTEM)
4915 You can then setup the @samp{$(HELLO_SYSTEM)} substitution from
4916 @file{configure.ac}:
4921 *linux*) HELLO_SYSTEM='hello-linux.$(OBJEXT)' ;;
4922 *) HELLO_SYSTEM='hello-generic.$(OBJEXT)' ;;
4924 AC_SUBST([HELLO_SYSTEM])
4928 In this case, the variable @code{HELLO_SYSTEM} should be replaced by
4929 either @file{hello-linux.o} or @file{hello-generic.o}, and added to
4930 both @code{hello_DEPENDENCIES} and @code{hello_LDADD} in order to be
4931 built and linked in.
4933 @subsubheading Conditional Compilation using Automake Conditionals
4935 An often simpler way to compile source files conditionally is to use
4936 Automake conditionals. For instance, you could use this
4937 @file{Makefile.am} construct to build the same @file{hello} example:
4940 bin_PROGRAMS = hello
4942 hello_SOURCES = hello-linux.c hello-common.c
4944 hello_SOURCES = hello-generic.c hello-common.c
4948 In this case, @file{configure.ac} should setup the @code{LINUX}
4949 conditional using @code{AM_CONDITIONAL} (@pxref{Conditionals}).
4951 When using conditionals like this you don't need to use the
4952 @code{EXTRA_} variable, because Automake will examine the contents of
4953 each variable to construct the complete list of source files.
4955 If your program uses a lot of files, you will probably prefer a
4956 conditional @samp{+=}.
4959 bin_PROGRAMS = hello
4960 hello_SOURCES = hello-common.c
4962 hello_SOURCES += hello-linux.c
4964 hello_SOURCES += hello-generic.c
4968 @node Conditional Programs
4969 @subsection Conditional compilation of programs
4970 @cindex Conditional programs
4971 @cindex Programs, conditional
4973 Sometimes it is useful to determine the programs that are to be built
4974 at configure time. For instance, GNU @code{cpio} only builds
4975 @code{mt} and @code{rmt} under special circumstances. The means to
4976 achieve conditional compilation of programs are the same you can use
4977 to compile source files conditionally: substitutions or conditionals.
4979 @subsubheading Conditional Programs using @command{configure} Substitutions
4981 @vindex EXTRA_PROGRAMS
4982 @cindex @code{EXTRA_PROGRAMS}, defined
4983 In this case, you must notify Automake of all the programs that can
4984 possibly be built, but at the same time cause the generated
4985 @file{Makefile.in} to use the programs specified by @command{configure}.
4986 This is done by having @command{configure} substitute values into each
4987 @code{_PROGRAMS} definition, while listing all optionally built programs
4988 in @code{EXTRA_PROGRAMS}.
4991 bin_PROGRAMS = cpio pax $(MT)
4992 libexec_PROGRAMS = $(RMT)
4993 EXTRA_PROGRAMS = mt rmt
4996 As explained in @ref{EXEEXT}, Automake will rewrite
4997 @code{bin_PROGRAMS}, @code{libexec_PROGRAMS}, and
4998 @code{EXTRA_PROGRAMS}, appending @samp{$(EXEEXT)} to each binary.
4999 Obviously it cannot rewrite values obtained at run-time through
5000 @command{configure} substitutions, therefore you should take care of
5001 appending @samp{$(EXEEXT)} yourself, as in @samp{AC_SUBST([MT],
5002 ['mt$@{EXEEXT@}'])}.
5004 @subsubheading Conditional Programs using Automake Conditionals
5006 You can also use Automake conditionals (@pxref{Conditionals}) to
5007 select programs to be built. In this case you don't have to worry
5008 about @samp{$(EXEEXT)} or @code{EXTRA_PROGRAMS}.
5010 @c Keep in sync with exeext.test.
5012 bin_PROGRAMS = cpio pax
5017 libexec_PROGRAMS = rmt
5023 @section Building a library
5025 @cindex @code{_LIBRARIES} primary, defined
5026 @cindex @code{LIBRARIES} primary, defined
5027 @cindex Primary variable, @code{LIBRARIES}
5030 @vindex lib_LIBRARIES
5031 @vindex pkglib_LIBRARIES
5032 @vindex noinst_LIBRARIES
5034 Building a library is much like building a program. In this case, the
5035 name of the primary is @code{LIBRARIES}. Libraries can be installed in
5036 @code{libdir} or @code{pkglibdir}.
5038 @xref{A Shared Library}, for information on how to build shared
5039 libraries using libtool and the @code{LTLIBRARIES} primary.
5041 Each @code{_LIBRARIES} variable is a list of the libraries to be built.
5042 For instance, to create a library named @file{libcpio.a}, but not install
5043 it, you would write:
5046 noinst_LIBRARIES = libcpio.a
5047 libcpio_a_SOURCES = @dots{}
5050 The sources that go into a library are determined exactly as they are
5051 for programs, via the @code{_SOURCES} variables. Note that the library
5052 name is canonicalized (@pxref{Canonicalization}), so the @code{_SOURCES}
5053 variable corresponding to @file{libcpio.a} is @samp{libcpio_a_SOURCES},
5054 not @samp{libcpio.a_SOURCES}.
5056 @vindex maude_LIBADD
5057 Extra objects can be added to a library using the
5058 @code{@var{library}_LIBADD} variable. This should be used for objects
5059 determined by @command{configure}. Again from @code{cpio}:
5061 @c Keep in sync with pr401c.test.
5063 libcpio_a_LIBADD = $(LIBOBJS) $(ALLOCA)
5066 In addition, sources for extra objects that will not exist until
5067 configure-time must be added to the @code{BUILT_SOURCES} variable
5070 Building a static library is done by compiling all object files, then
5071 by invoking @samp{$(AR) $(ARFLAGS)} followed by the name of the
5072 library and the list of objects, and finally by calling
5073 @samp{$(RANLIB)} on that library. You should call
5074 @code{AC_PROG_RANLIB} from your @file{configure.ac} to define
5075 @code{RANLIB} (Automake will complain otherwise). You should also
5076 call @code{AM_PROG_AR} to define @code{AR}, in order to support unusual
5077 archivers such as Microsoft lib. @code{ARFLAGS} will default to
5078 @code{cru}; you can override this variable by setting it in your
5079 @file{Makefile.am} or by @code{AC_SUBST}ing it from your
5080 @file{configure.ac}. You can override the @code{AR} variable by
5081 defining a per-library @code{maude_AR} variable (@pxref{Program and
5082 Library Variables}).
5084 @cindex Empty libraries
5085 Be careful when selecting library components conditionally. Because
5086 building an empty library is not portable, you should ensure that any
5087 library always contains at least one object.
5089 To use a static library when building a program, add it to
5090 @code{LDADD} for this program. In the following example, the program
5091 @file{cpio} is statically linked with the library @file{libcpio.a}.
5094 noinst_LIBRARIES = libcpio.a
5095 libcpio_a_SOURCES = @dots{}
5098 cpio_SOURCES = cpio.c @dots{}
5099 cpio_LDADD = libcpio.a
5103 @node A Shared Library
5104 @section Building a Shared Library
5106 @cindex Shared libraries, support for
5108 Building shared libraries portably is a relatively complex matter.
5109 For this reason, GNU Libtool (@pxref{Top, , Introduction, libtool, The
5110 Libtool Manual}) was created to help build shared libraries in a
5111 platform-independent way.
5114 * Libtool Concept:: Introducing Libtool
5115 * Libtool Libraries:: Declaring Libtool Libraries
5116 * Conditional Libtool Libraries:: Building Libtool Libraries Conditionally
5117 * Conditional Libtool Sources:: Choosing Library Sources Conditionally
5118 * Libtool Convenience Libraries:: Building Convenience Libtool Libraries
5119 * Libtool Modules:: Building Libtool Modules
5120 * Libtool Flags:: Using _LIBADD, _LDFLAGS, and _LIBTOOLFLAGS
5121 * LTLIBOBJS:: Using $(LTLIBOBJS) and $(LTALLOCA)
5122 * Libtool Issues:: Common Issues Related to Libtool's Use
5125 @node Libtool Concept
5126 @subsection The Libtool Concept
5128 @cindex @command{libtool}, introduction
5129 @cindex libtool library, definition
5130 @cindex suffix @file{.la}, defined
5131 @cindex @file{.la} suffix, defined
5133 Libtool abstracts shared and static libraries into a unified concept
5134 henceforth called @dfn{libtool libraries}. Libtool libraries are
5135 files using the @file{.la} suffix, and can designate a static library,
5136 a shared library, or maybe both. Their exact nature cannot be
5137 determined until @file{./configure} is run: not all platforms support
5138 all kinds of libraries, and users can explicitly select which
5139 libraries should be built. (However the package's maintainers can
5140 tune the default, @pxref{AC_PROG_LIBTOOL, , The @code{AC_PROG_LIBTOOL}
5141 macro, libtool, The Libtool Manual}.)
5143 @cindex suffix @file{.lo}, defined
5144 Because object files for shared and static libraries must be compiled
5145 differently, libtool is also used during compilation. Object files
5146 built by libtool are called @dfn{libtool objects}: these are files
5147 using the @file{.lo} suffix. Libtool libraries are built from these
5150 You should not assume anything about the structure of @file{.la} or
5151 @file{.lo} files and how libtool constructs them: this is libtool's
5152 concern, and the last thing one wants is to learn about libtool's
5153 guts. However the existence of these files matters, because they are
5154 used as targets and dependencies in @file{Makefile}s rules when
5155 building libtool libraries. There are situations where you may have
5156 to refer to these, for instance when expressing dependencies for
5157 building source files conditionally (@pxref{Conditional Libtool
5160 @cindex @file{libltdl}, introduction
5162 People considering writing a plug-in system, with dynamically loaded
5163 modules, should look into @file{libltdl}: libtool's dlopening library
5164 (@pxref{Using libltdl, , Using libltdl, libtool, The Libtool Manual}).
5165 This offers a portable dlopening facility to load libtool libraries
5166 dynamically, and can also achieve static linking where unavoidable.
5168 Before we discuss how to use libtool with Automake in details, it
5169 should be noted that the libtool manual also has a section about how
5170 to use Automake with libtool (@pxref{Using Automake, , Using Automake
5171 with Libtool, libtool, The Libtool Manual}).
5173 @node Libtool Libraries
5174 @subsection Building Libtool Libraries
5176 @cindex @code{_LTLIBRARIES} primary, defined
5177 @cindex @code{LTLIBRARIES} primary, defined
5178 @cindex Primary variable, @code{LTLIBRARIES}
5179 @cindex Example of shared libraries
5180 @vindex lib_LTLIBRARIES
5181 @vindex pkglib_LTLIBRARIES
5182 @vindex _LTLIBRARIES
5184 Automake uses libtool to build libraries declared with the
5185 @code{LTLIBRARIES} primary. Each @code{_LTLIBRARIES} variable is a
5186 list of libtool libraries to build. For instance, to create a libtool
5187 library named @file{libgettext.la}, and install it in @code{libdir},
5191 lib_LTLIBRARIES = libgettext.la
5192 libgettext_la_SOURCES = gettext.c gettext.h @dots{}
5195 Automake predefines the variable @code{pkglibdir}, so you can use
5196 @code{pkglib_LTLIBRARIES} to install libraries in
5197 @samp{$(libdir)/@@PACKAGE@@/}.
5199 If @file{gettext.h} is a public header file that needs to be installed
5200 in order for people to use the library, it should be declared using a
5201 @code{_HEADERS} variable, not in @code{libgettext_la_SOURCES}.
5202 Headers listed in the latter should be internal headers that are not
5203 part of the public interface.
5206 lib_LTLIBRARIES = libgettext.la
5207 libgettext_la_SOURCES = gettext.c @dots{}
5208 include_HEADERS = gettext.h @dots{}
5211 A package can build and install such a library along with other
5212 programs that use it. This dependency should be specified using
5213 @code{LDADD}. The following example builds a program named
5214 @file{hello} that is linked with @file{libgettext.la}.
5217 lib_LTLIBRARIES = libgettext.la
5218 libgettext_la_SOURCES = gettext.c @dots{}
5220 bin_PROGRAMS = hello
5221 hello_SOURCES = hello.c @dots{}
5222 hello_LDADD = libgettext.la
5226 Whether @file{hello} is statically or dynamically linked with
5227 @file{libgettext.la} is not yet known: this will depend on the
5228 configuration of libtool and the capabilities of the host.
5231 @node Conditional Libtool Libraries
5232 @subsection Building Libtool Libraries Conditionally
5233 @cindex libtool libraries, conditional
5234 @cindex conditional libtool libraries
5236 Like conditional programs (@pxref{Conditional Programs}), there are
5237 two main ways to build conditional libraries: using Automake
5238 conditionals or using Autoconf @code{AC_SUBST}itutions.
5240 The important implementation detail you have to be aware of is that
5241 the place where a library will be installed matters to libtool: it
5242 needs to be indicated @emph{at link-time} using the @option{-rpath}
5245 For libraries whose destination directory is known when Automake runs,
5246 Automake will automatically supply the appropriate @option{-rpath}
5247 option to libtool. This is the case for libraries listed explicitly in
5248 some installable @code{_LTLIBRARIES} variables such as
5249 @code{lib_LTLIBRARIES}.
5251 However, for libraries determined at configure time (and thus
5252 mentioned in @code{EXTRA_LTLIBRARIES}), Automake does not know the
5253 final installation directory. For such libraries you must add the
5254 @option{-rpath} option to the appropriate @code{_LDFLAGS} variable by
5257 The examples below illustrate the differences between these two methods.
5259 Here is an example where @code{WANTEDLIBS} is an @code{AC_SUBST}ed
5260 variable set at @file{./configure}-time to either @file{libfoo.la},
5261 @file{libbar.la}, both, or none. Although @samp{$(WANTEDLIBS)}
5262 appears in the @code{lib_LTLIBRARIES}, Automake cannot guess it
5263 relates to @file{libfoo.la} or @file{libbar.la} at the time it creates
5264 the link rule for these two libraries. Therefore the @option{-rpath}
5265 argument must be explicitly supplied.
5267 @c Keep in sync with ltcond.test.
5269 EXTRA_LTLIBRARIES = libfoo.la libbar.la
5270 lib_LTLIBRARIES = $(WANTEDLIBS)
5271 libfoo_la_SOURCES = foo.c @dots{}
5272 libfoo_la_LDFLAGS = -rpath '$(libdir)'
5273 libbar_la_SOURCES = bar.c @dots{}
5274 libbar_la_LDFLAGS = -rpath '$(libdir)'
5277 Here is how the same @file{Makefile.am} would look using Automake
5278 conditionals named @code{WANT_LIBFOO} and @code{WANT_LIBBAR}. Now
5279 Automake is able to compute the @option{-rpath} setting itself, because
5280 it's clear that both libraries will end up in @samp{$(libdir)} if they
5283 @c Keep in sync with ltcond.test.
5287 lib_LTLIBRARIES += libfoo.la
5290 lib_LTLIBRARIES += libbar.la
5292 libfoo_la_SOURCES = foo.c @dots{}
5293 libbar_la_SOURCES = bar.c @dots{}
5296 @node Conditional Libtool Sources
5297 @subsection Libtool Libraries with Conditional Sources
5299 Conditional compilation of sources in a library can be achieved in the
5300 same way as conditional compilation of sources in a program
5301 (@pxref{Conditional Sources}). The only difference is that
5302 @code{_LIBADD} should be used instead of @code{_LDADD} and that it
5303 should mention libtool objects (@file{.lo} files).
5305 So, to mimic the @file{hello} example from @ref{Conditional Sources},
5306 we could build a @file{libhello.la} library using either
5307 @file{hello-linux.c} or @file{hello-generic.c} with the following
5310 @c Keep in sync with ltcond2.test.
5312 lib_LTLIBRARIES = libhello.la
5313 libhello_la_SOURCES = hello-common.c
5314 EXTRA_libhello_la_SOURCES = hello-linux.c hello-generic.c
5315 libhello_la_LIBADD = $(HELLO_SYSTEM)
5316 libhello_la_DEPENDENCIES = $(HELLO_SYSTEM)
5320 And make sure @command{configure} defines @code{HELLO_SYSTEM} as
5321 either @file{hello-linux.lo} or @file{hello-@-generic.lo}.
5323 Or we could simply use an Automake conditional as follows.
5325 @c Keep in sync with ltcond2.test.
5327 lib_LTLIBRARIES = libhello.la
5328 libhello_la_SOURCES = hello-common.c
5330 libhello_la_SOURCES += hello-linux.c
5332 libhello_la_SOURCES += hello-generic.c
5336 @node Libtool Convenience Libraries
5337 @subsection Libtool Convenience Libraries
5338 @cindex convenience libraries, libtool
5339 @cindex libtool convenience libraries
5340 @vindex noinst_LTLIBRARIES
5341 @vindex check_LTLIBRARIES
5343 Sometimes you want to build libtool libraries that should not be
5344 installed. These are called @dfn{libtool convenience libraries} and
5345 are typically used to encapsulate many sublibraries, later gathered
5346 into one big installed library.
5348 Libtool convenience libraries are declared by directory-less variables
5349 such as @code{noinst_LTLIBRARIES}, @code{check_LTLIBRARIES}, or even
5350 @code{EXTRA_LTLIBRARIES}. Unlike installed libtool libraries they do
5351 not need an @option{-rpath} flag at link time (actually this is the only
5354 Convenience libraries listed in @code{noinst_LTLIBRARIES} are always
5355 built. Those listed in @code{check_LTLIBRARIES} are built only upon
5356 @samp{make check}. Finally, libraries listed in
5357 @code{EXTRA_LTLIBRARIES} are never built explicitly: Automake outputs
5358 rules to build them, but if the library does not appear as a Makefile
5359 dependency anywhere it won't be built (this is why
5360 @code{EXTRA_LTLIBRARIES} is used for conditional compilation).
5362 Here is a sample setup merging libtool convenience libraries from
5363 subdirectories into one main @file{libtop.la} library.
5365 @c Keep in sync with ltconv.test.
5367 # -- Top-level Makefile.am --
5368 SUBDIRS = sub1 sub2 @dots{}
5369 lib_LTLIBRARIES = libtop.la
5371 libtop_la_LIBADD = \
5376 # -- sub1/Makefile.am --
5377 noinst_LTLIBRARIES = libsub1.la
5378 libsub1_la_SOURCES = @dots{}
5380 # -- sub2/Makefile.am --
5381 # showing nested convenience libraries
5382 SUBDIRS = sub2.1 sub2.2 @dots{}
5383 noinst_LTLIBRARIES = libsub2.la
5384 libsub2_la_SOURCES =
5385 libsub2_la_LIBADD = \
5391 When using such setup, beware that @command{automake} will assume
5392 @file{libtop.la} is to be linked with the C linker. This is because
5393 @code{libtop_la_SOURCES} is empty, so @command{automake} picks C as
5394 default language. If @code{libtop_la_SOURCES} was not empty,
5395 @command{automake} would select the linker as explained in @ref{How
5396 the Linker is Chosen}.
5398 If one of the sublibraries contains non-C source, it is important that
5399 the appropriate linker be chosen. One way to achieve this is to
5400 pretend that there is such a non-C file among the sources of the
5401 library, thus forcing @command{automake} to select the appropriate
5402 linker. Here is the top-level @file{Makefile} of our example updated
5403 to force C++ linking.
5406 SUBDIRS = sub1 sub2 @dots{}
5407 lib_LTLIBRARIES = libtop.la
5409 # Dummy C++ source to cause C++ linking.
5410 nodist_EXTRA_libtop_la_SOURCES = dummy.cxx
5411 libtop_la_LIBADD = \
5417 @samp{EXTRA_*_SOURCES} variables are used to keep track of source
5418 files that might be compiled (this is mostly useful when doing
5419 conditional compilation using @code{AC_SUBST}, @pxref{Conditional
5420 Libtool Sources}), and the @code{nodist_} prefix means the listed
5421 sources are not to be distributed (@pxref{Program and Library
5422 Variables}). In effect the file @file{dummy.cxx} does not need to
5423 exist in the source tree. Of course if you have some real source file
5424 to list in @code{libtop_la_SOURCES} there is no point in cheating with
5425 @code{nodist_EXTRA_libtop_la_SOURCES}.
5428 @node Libtool Modules
5429 @subsection Libtool Modules
5430 @cindex modules, libtool
5431 @cindex libtool modules
5432 @cindex @option{-module}, libtool
5434 These are libtool libraries meant to be dlopened. They are
5435 indicated to libtool by passing @option{-module} at link-time.
5438 pkglib_LTLIBRARIES = mymodule.la
5439 mymodule_la_SOURCES = doit.c
5440 mymodule_la_LDFLAGS = -module
5443 Ordinarily, Automake requires that a library's name start with
5444 @code{lib}. However, when building a dynamically loadable module you
5445 might wish to use a "nonstandard" name. Automake will not complain
5446 about such nonstandard names if it knows the library being built is a
5447 libtool module, i.e., if @option{-module} explicitly appears in the
5448 library's @code{_LDFLAGS} variable (or in the common @code{AM_LDFLAGS}
5449 variable when no per-library @code{_LDFLAGS} variable is defined).
5451 As always, @code{AC_SUBST} variables are black boxes to Automake since
5452 their values are not yet known when @command{automake} is run.
5453 Therefore if @option{-module} is set via such a variable, Automake
5454 cannot notice it and will proceed as if the library was an ordinary
5455 libtool library, with strict naming.
5457 If @code{mymodule_la_SOURCES} is not specified, then it defaults to
5458 the single file @file{mymodule.c} (@pxref{Default _SOURCES}).
5461 @subsection @code{_LIBADD}, @code{_LDFLAGS}, and @code{_LIBTOOLFLAGS}
5462 @cindex @code{_LIBADD}, libtool
5463 @cindex @code{_LDFLAGS}, libtool
5464 @cindex @code{_LIBTOOLFLAGS}, libtool
5465 @vindex AM_LIBTOOLFLAGS
5466 @vindex LIBTOOLFLAGS
5467 @vindex maude_LIBTOOLFLAGS
5469 As shown in previous sections, the @samp{@var{library}_LIBADD}
5470 variable should be used to list extra libtool objects (@file{.lo}
5471 files) or libtool libraries (@file{.la}) to add to @var{library}.
5473 The @samp{@var{library}_LDFLAGS} variable is the place to list
5474 additional libtool linking flags, such as @option{-version-info},
5475 @option{-static}, and a lot more. @xref{Link mode, , Link mode,
5476 libtool, The Libtool Manual}.
5478 The @command{libtool} command has two kinds of options: mode-specific
5479 options and generic options. Mode-specific options such as the
5480 aforementioned linking flags should be lumped with the other flags
5481 passed to the tool invoked by @command{libtool} (hence the use of
5482 @samp{@var{library}_LDFLAGS} for libtool linking flags). Generic
5483 options include @option{--tag=@var{tag}} and @option{--silent}
5484 (@pxref{Invoking libtool, , Invoking @command{libtool}, libtool, The
5485 Libtool Manual} for more options) should appear before the mode
5486 selection on the command line; in @file{Makefile.am}s they should
5487 be listed in the @samp{@var{library}_LIBTOOLFLAGS} variable.
5489 If @samp{@var{library}_LIBTOOLFLAGS} is not defined, then the variable
5490 @code{AM_LIBTOOLFLAGS} is used instead.
5492 These flags are passed to libtool after the @option{--tag=@var{tag}}
5493 option computed by Automake (if any), so
5494 @samp{@var{library}_LIBTOOLFLAGS} (or @code{AM_LIBTOOLFLAGS}) is a
5495 good place to override or supplement the @option{--tag=@var{tag}}
5498 The libtool rules also use a @code{LIBTOOLFLAGS} variable that should
5499 not be set in @file{Makefile.am}: this is a user variable (@pxref{Flag
5500 Variables Ordering}. It allows users to run @samp{make
5501 LIBTOOLFLAGS=--silent}, for instance. Note that the verbosity of
5502 @command{libtool} can also be influenced with the Automake
5503 @option{silent-rules} option (@pxref{Options}).
5506 @node LTLIBOBJS, Libtool Issues, Libtool Flags, A Shared Library
5507 @subsection @code{LTLIBOBJS} and @code{LTALLOCA}
5508 @cindex @code{LTLIBOBJS}, special handling
5509 @cindex @code{LIBOBJS}, and Libtool
5510 @cindex @code{LTALLOCA}, special handling
5511 @cindex @code{ALLOCA}, and Libtool
5518 Where an ordinary library might include @samp{$(LIBOBJS)} or
5519 @samp{$(ALLOCA)} (@pxref{LIBOBJS}), a libtool library must use
5520 @samp{$(LTLIBOBJS)} or @samp{$(LTALLOCA)}. This is required because
5521 the object files that libtool operates on do not necessarily end in
5524 Nowadays, the computation of @code{LTLIBOBJS} from @code{LIBOBJS} is
5525 performed automatically by Autoconf (@pxref{AC_LIBOBJ vs LIBOBJS, ,
5526 @code{AC_LIBOBJ} vs.@: @code{LIBOBJS}, autoconf, The Autoconf Manual}).
5528 @node Libtool Issues
5529 @subsection Common Issues Related to Libtool's Use
5532 * Error required file ltmain.sh not found:: The need to run libtoolize
5533 * Objects created both with libtool and without:: Avoid a specific build race
5536 @node Error required file ltmain.sh not found
5537 @subsubsection Error: @samp{required file `./ltmain.sh' not found}
5538 @cindex @file{ltmain.sh} not found
5539 @cindex @command{libtoolize}, no longer run by @command{automake}
5540 @cindex @command{libtoolize} and @command{autoreconf}
5541 @cindex @command{autoreconf} and @command{libtoolize}
5542 @cindex @file{bootstrap.sh} and @command{autoreconf}
5543 @cindex @file{autogen.sh} and @command{autoreconf}
5545 Libtool comes with a tool called @command{libtoolize} that will
5546 install libtool's supporting files into a package. Running this
5547 command will install @file{ltmain.sh}. You should execute it before
5548 @command{aclocal} and @command{automake}.
5550 People upgrading old packages to newer autotools are likely to face
5551 this issue because older Automake versions used to call
5552 @command{libtoolize}. Therefore old build scripts do not call
5553 @command{libtoolize}.
5555 Since Automake 1.6, it has been decided that running
5556 @command{libtoolize} was none of Automake's business. Instead, that
5557 functionality has been moved into the @command{autoreconf} command
5558 (@pxref{autoreconf Invocation, , Using @command{autoreconf}, autoconf,
5559 The Autoconf Manual}). If you do not want to remember what to run and
5560 when, just learn the @command{autoreconf} command. Hopefully,
5561 replacing existing @file{bootstrap.sh} or @file{autogen.sh} scripts by
5562 a call to @command{autoreconf} should also free you from any similar
5563 incompatible change in the future.
5565 @node Objects created both with libtool and without
5566 @subsubsection Objects @samp{created with both libtool and without}
5568 Sometimes, the same source file is used both to build a libtool
5569 library and to build another non-libtool target (be it a program or
5572 Let's consider the following @file{Makefile.am}.
5576 prog_SOURCES = prog.c foo.c @dots{}
5578 lib_LTLIBRARIES = libfoo.la
5579 libfoo_la_SOURCES = foo.c @dots{}
5583 (In this trivial case the issue could be avoided by linking
5584 @file{libfoo.la} with @file{prog} instead of listing @file{foo.c} in
5585 @code{prog_SOURCES}. But let's assume we really want to keep
5586 @file{prog} and @file{libfoo.la} separate.)
5588 Technically, it means that we should build @file{foo.$(OBJEXT)} for
5589 @file{prog}, and @file{foo.lo} for @file{libfoo.la}. The problem is
5590 that in the course of creating @file{foo.lo}, libtool may erase (or
5591 replace) @file{foo.$(OBJEXT)}, and this cannot be avoided.
5593 Therefore, when Automake detects this situation it will complain
5594 with a message such as
5596 object `foo.$(OBJEXT)' created both with libtool and without
5599 A workaround for this issue is to ensure that these two objects get
5600 different basenames. As explained in @ref{Renamed Objects}, this
5601 happens automatically when per-targets flags are used.
5605 prog_SOURCES = prog.c foo.c @dots{}
5606 prog_CFLAGS = $(AM_CFLAGS)
5608 lib_LTLIBRARIES = libfoo.la
5609 libfoo_la_SOURCES = foo.c @dots{}
5613 Adding @samp{prog_CFLAGS = $(AM_CFLAGS)} is almost a no-op, because
5614 when the @code{prog_CFLAGS} is defined, it is used instead of
5615 @code{AM_CFLAGS}. However as a side effect it will cause
5616 @file{prog.c} and @file{foo.c} to be compiled as
5617 @file{prog-prog.$(OBJEXT)} and @file{prog-foo.$(OBJEXT)}, which solves
5620 @node Program and Library Variables
5621 @section Program and Library Variables
5623 Associated with each program is a collection of variables that can be
5624 used to modify how that program is built. There is a similar list of
5625 such variables for each library. The canonical name of the program (or
5626 library) is used as a base for naming these variables.
5628 In the list below, we use the name ``maude'' to refer to the program or
5629 library. In your @file{Makefile.am} you would replace this with the
5630 canonical name of your program. This list also refers to ``maude'' as a
5631 program, but in general the same rules apply for both static and dynamic
5632 libraries; the documentation below notes situations where programs and
5637 This variable, if it exists, lists all the source files that are
5638 compiled to build the program. These files are added to the
5639 distribution by default. When building the program, Automake will cause
5640 each source file to be compiled to a single @file{.o} file (or
5641 @file{.lo} when using libtool). Normally these object files are named
5642 after the source file, but other factors can change this. If a file in
5643 the @code{_SOURCES} variable has an unrecognized extension, Automake
5644 will do one of two things with it. If a suffix rule exists for turning
5645 files with the unrecognized extension into @file{.o} files, then
5646 @command{automake} will treat this file as it will any other source file
5647 (@pxref{Support for Other Languages}). Otherwise, the file will be
5648 ignored as though it were a header file.
5650 The prefixes @code{dist_} and @code{nodist_} can be used to control
5651 whether files listed in a @code{_SOURCES} variable are distributed.
5652 @code{dist_} is redundant, as sources are distributed by default, but it
5653 can be specified for clarity if desired.
5655 It is possible to have both @code{dist_} and @code{nodist_} variants of
5656 a given @code{_SOURCES} variable at once; this lets you easily
5657 distribute some files and not others, for instance:
5660 nodist_maude_SOURCES = nodist.c
5661 dist_maude_SOURCES = dist-me.c
5664 By default the output file (on Unix systems, the @file{.o} file) will
5665 be put into the current build directory. However, if the option
5666 @option{subdir-objects} is in effect in the current directory then the
5667 @file{.o} file will be put into the subdirectory named after the
5668 source file. For instance, with @option{subdir-objects} enabled,
5669 @file{sub/dir/file.c} will be compiled to @file{sub/dir/file.o}. Some
5670 people prefer this mode of operation. You can specify
5671 @option{subdir-objects} in @code{AUTOMAKE_OPTIONS} (@pxref{Options}).
5672 @cindex Subdirectory, objects in
5673 @cindex Objects in subdirectory
5676 @item EXTRA_maude_SOURCES
5677 Automake needs to know the list of files you intend to compile
5678 @emph{statically}. For one thing, this is the only way Automake has of
5679 knowing what sort of language support a given @file{Makefile.in}
5680 requires. @footnote{There are other, more obscure reasons for
5681 this limitation as well.} This means that, for example, you can't put a
5682 configure substitution like @samp{@@my_sources@@} into a @samp{_SOURCES}
5683 variable. If you intend to conditionally compile source files and use
5684 @file{configure} to substitute the appropriate object names into, e.g.,
5685 @code{_LDADD} (see below), then you should list the corresponding source
5686 files in the @code{EXTRA_} variable.
5688 This variable also supports @code{dist_} and @code{nodist_} prefixes.
5689 For instance, @code{nodist_EXTRA_maude_SOURCES} would list extra
5690 sources that may need to be built, but should not be distributed.
5693 A static library is created by default by invoking @samp{$(AR)
5694 $(ARFLAGS)} followed by the name of the library and then the objects
5695 being put into the library. You can override this by setting the
5696 @code{_AR} variable. This is usually used with C++; some C++
5697 compilers require a special invocation in order to instantiate all the
5698 templates that should go into a library. For instance, the SGI C++
5699 compiler likes this variable set like so:
5701 libmaude_a_AR = $(CXX) -ar -o
5705 Extra objects can be added to a @emph{library} using the @code{_LIBADD}
5706 variable. For instance, this should be used for objects determined by
5707 @command{configure} (@pxref{A Library}).
5709 In the case of libtool libraries, @code{maude_LIBADD} can also refer
5710 to other libtool libraries.
5713 Extra objects (@file{*.$(OBJEXT)}) and libraries (@file{*.a},
5714 @file{*.la}) can be added to a @emph{program} by listing them in the
5715 @code{_LDADD} variable. For instance, this should be used for objects
5716 determined by @command{configure} (@pxref{Linking}).
5718 @code{_LDADD} and @code{_LIBADD} are inappropriate for passing
5719 program-specific linker flags (except for @option{-l}, @option{-L},
5720 @option{-dlopen} and @option{-dlpreopen}). Use the @code{_LDFLAGS} variable
5723 For instance, if your @file{configure.ac} uses @code{AC_PATH_XTRA}, you
5724 could link your program against the X libraries like so:
5727 maude_LDADD = $(X_PRE_LIBS) $(X_LIBS) $(X_EXTRA_LIBS)
5730 We recommend that you use @option{-l} and @option{-L} only when
5731 referring to third-party libraries, and give the explicit file names
5732 of any library built by your package. Doing so will ensure that
5733 @code{maude_DEPENDENCIES} (see below) is correctly defined by default.
5736 This variable is used to pass extra flags to the link step of a program
5737 or a shared library. It overrides the @code{AM_LDFLAGS} variable.
5739 @item maude_LIBTOOLFLAGS
5740 This variable is used to pass extra options to @command{libtool}.
5741 It overrides the @code{AM_LIBTOOLFLAGS} variable.
5742 These options are output before @command{libtool}'s @option{--mode=@var{mode}}
5743 option, so they should not be mode-specific options (those belong to
5744 the compiler or linker flags). @xref{Libtool Flags}.
5746 @item maude_DEPENDENCIES
5747 It is also occasionally useful to have a target (program or library)
5748 depend on some other file that is not actually part of that target.
5749 This can be done using the @code{_DEPENDENCIES} variable. Each
5750 target depends on the contents of such a variable, but no further
5751 interpretation is done.
5753 Since these dependencies are associated to the link rule used to
5754 create the programs they should normally list files used by the link
5755 command. That is @file{*.$(OBJEXT)}, @file{*.a}, or @file{*.la} files
5756 for programs; @file{*.lo} and @file{*.la} files for Libtool libraries;
5757 and @file{*.$(OBJEXT)} files for static libraries. In rare cases you
5758 may need to add other kinds of files such as linker scripts, but
5759 @emph{listing a source file in @code{_DEPENDENCIES} is wrong}. If
5760 some source file needs to be built before all the components of a
5761 program are built, consider using the @code{BUILT_SOURCES} variable
5764 If @code{_DEPENDENCIES} is not supplied, it is computed by Automake.
5765 The automatically-assigned value is the contents of @code{_LDADD} or
5766 @code{_LIBADD}, with most configure substitutions, @option{-l}, @option{-L},
5767 @option{-dlopen} and @option{-dlpreopen} options removed. The configure
5768 substitutions that are left in are only @samp{$(LIBOBJS)} and
5769 @samp{$(ALLOCA)}; these are left because it is known that they will not
5770 cause an invalid value for @code{_DEPENDENCIES} to be generated.
5772 @code{_DEPENDENCIES} is more likely used to perform conditional
5773 compilation using an @code{AC_SUBST} variable that contains a list of
5774 objects. @xref{Conditional Sources}, and @ref{Conditional Libtool
5778 You can override the linker on a per-program basis. By default the
5779 linker is chosen according to the languages used by the program. For
5780 instance, a program that includes C++ source code would use the C++
5781 compiler to link. The @code{_LINK} variable must hold the name of a
5782 command that can be passed all the @file{.o} file names and libraries
5783 to link against as arguments. Note that the name of the underlying
5784 program is @emph{not} passed to @code{_LINK}; typically one uses
5788 maude_LINK = $(CCLD) -magic -o $@@
5791 If a @code{_LINK} variable is not supplied, it may still be generated
5792 and used by Automake due to the use of per-target link flags such as
5793 @code{_CFLAGS}, @code{_LDFLAGS} or @code{_LIBTOOLFLAGS}, in cases where
5796 @item maude_CCASFLAGS
5798 @itemx maude_CPPFLAGS
5799 @itemx maude_CXXFLAGS
5801 @itemx maude_GCJFLAGS
5803 @itemx maude_OBJCFLAGS
5805 @itemx maude_UPCFLAGS
5807 @cindex per-target compilation flags, defined
5808 Automake allows you to set compilation flags on a per-program (or
5809 per-library) basis. A single source file can be included in several
5810 programs, and it will potentially be compiled with different flags for
5811 each program. This works for any language directly supported by
5812 Automake. These @dfn{per-target compilation flags} are
5822 @samp{_UPCFLAGS}, and
5825 When using a per-target compilation flag, Automake will choose a
5826 different name for the intermediate object files. Ordinarily a file
5827 like @file{sample.c} will be compiled to produce @file{sample.o}.
5828 However, if the program's @code{_CFLAGS} variable is set, then the
5829 object file will be named, for instance, @file{maude-sample.o}. (See
5830 also @ref{Renamed Objects}.) The use of per-target compilation flags
5831 with C sources requires that the macro @code{AM_PROG_CC_C_O} be called
5832 from @file{configure.ac}.
5834 In compilations with per-target flags, the ordinary @samp{AM_} form of
5835 the flags variable is @emph{not} automatically included in the
5836 compilation (however, the user form of the variable @emph{is} included).
5837 So for instance, if you want the hypothetical @file{maude} compilations
5838 to also use the value of @code{AM_CFLAGS}, you would need to write:
5841 maude_CFLAGS = @dots{} your flags @dots{} $(AM_CFLAGS)
5844 @xref{Flag Variables Ordering}, for more discussion about the
5845 interaction between user variables, @samp{AM_} shadow variables, and
5846 per-target variables.
5848 @item maude_SHORTNAME
5849 On some platforms the allowable file names are very short. In order to
5850 support these systems and per-target compilation flags at the same
5851 time, Automake allows you to set a ``short name'' that will influence
5852 how intermediate object files are named. For instance, in the following
5856 bin_PROGRAMS = maude
5857 maude_CPPFLAGS = -DSOMEFLAG
5859 maude_SOURCES = sample.c @dots{}
5863 the object file would be named @file{m-sample.o} rather than
5864 @file{maude-sample.o}.
5866 This facility is rarely needed in practice,
5867 and we recommend avoiding it until you find it is required.
5870 @node Default _SOURCES
5871 @section Default @code{_SOURCES}
5875 @cindex @code{_SOURCES}, default
5876 @cindex default @code{_SOURCES}
5877 @vindex AM_DEFAULT_SOURCE_EXT
5879 @code{_SOURCES} variables are used to specify source files of programs
5880 (@pxref{A Program}), libraries (@pxref{A Library}), and Libtool
5881 libraries (@pxref{A Shared Library}).
5883 When no such variable is specified for a target, Automake will define
5884 one itself. The default is to compile a single C file whose base name
5885 is the name of the target itself, with any extension replaced by
5886 @code{AM_DEFAULT_SOURCE_EXT}, which defaults to @file{.c}.
5888 For example if you have the following somewhere in your
5889 @file{Makefile.am} with no corresponding @code{libfoo_a_SOURCES}:
5892 lib_LIBRARIES = libfoo.a sub/libc++.a
5896 @file{libfoo.a} will be built using a default source file named
5897 @file{libfoo.c}, and @file{sub/libc++.a} will be built from
5898 @file{sub/libc++.c}. (In older versions @file{sub/libc++.a}
5899 would be built from @file{sub_libc___a.c}, i.e., the default source
5900 was the canonized name of the target, with @file{.c} appended.
5901 We believe the new behavior is more sensible, but for backward
5902 compatibility @command{automake} will use the old name if a file or a rule
5903 with that name exists and @code{AM_DEFAULT_SOURCE_EXT} is not used.)
5905 @cindex @code{check_PROGRAMS} example
5906 @vindex check_PROGRAMS
5907 Default sources are mainly useful in test suites, when building many
5908 test programs each from a single source. For instance, in
5911 check_PROGRAMS = test1 test2 test3
5912 AM_DEFAULT_SOURCE_EXT = .cpp
5916 @file{test1}, @file{test2}, and @file{test3} will be built
5917 from @file{test1.cpp}, @file{test2.cpp}, and @file{test3.cpp}.
5918 Without the last line, they will be built from @file{test1.c},
5919 @file{test2.c}, and @file{test3.c}.
5921 @cindex Libtool modules, default source example
5922 @cindex default source, Libtool modules example
5923 Another case where this is convenient is building many Libtool modules
5924 (@file{module@var{n}.la}), each defined in its own file
5925 (@file{module@var{n}.c}).
5928 AM_LDFLAGS = -module
5929 lib_LTLIBRARIES = module1.la module2.la module3.la
5932 @cindex empty @code{_SOURCES}
5933 @cindex @code{_SOURCES}, empty
5934 Finally, there is one situation where this default source computation
5935 needs to be avoided: when a target should not be built from sources.
5936 We already saw such an example in @ref{true}; this happens when all
5937 the constituents of a target have already been compiled and just need
5938 to be combined using a @code{_LDADD} variable. Then it is necessary
5939 to define an empty @code{_SOURCES} variable, so that @command{automake}
5940 does not compute a default.
5943 bin_PROGRAMS = target
5945 target_LDADD = libmain.a libmisc.a
5949 @section Special handling for @code{LIBOBJS} and @code{ALLOCA}
5951 @cindex @code{LIBOBJS}, example
5952 @cindex @code{ALLOCA}, example
5953 @cindex @code{LIBOBJS}, special handling
5954 @cindex @code{ALLOCA}, special handling
5960 The @samp{$(LIBOBJS)} and @samp{$(ALLOCA)} variables list object
5961 files that should be compiled into the project to provide an
5962 implementation for functions that are missing or broken on the host
5963 system. They are substituted by @file{configure}.
5967 These variables are defined by Autoconf macros such as
5968 @code{AC_LIBOBJ}, @code{AC_REPLACE_FUNCS} (@pxref{Generic Functions, ,
5969 Generic Function Checks, autoconf, The Autoconf Manual}), or
5970 @code{AC_FUNC_ALLOCA} (@pxref{Particular Functions, , Particular
5971 Function Checks, autoconf, The Autoconf Manual}). Many other Autoconf
5972 macros call @code{AC_LIBOBJ} or @code{AC_REPLACE_FUNCS} to
5973 populate @samp{$(LIBOBJS)}.
5975 @acindex AC_LIBSOURCE
5977 Using these variables is very similar to doing conditional compilation
5978 using @code{AC_SUBST} variables, as described in @ref{Conditional
5979 Sources}. That is, when building a program, @samp{$(LIBOBJS)} and
5980 @samp{$(ALLOCA)} should be added to the associated @samp{*_LDADD}
5981 variable, or to the @samp{*_LIBADD} variable when building a library.
5982 However there is no need to list the corresponding sources in
5983 @samp{EXTRA_*_SOURCES} nor to define @samp{*_DEPENDENCIES}. Automake
5984 automatically adds @samp{$(LIBOBJS)} and @samp{$(ALLOCA)} to the
5985 dependencies, and it will discover the list of corresponding source
5986 files automatically (by tracing the invocations of the
5987 @code{AC_LIBSOURCE} Autoconf macros). However, if you have already
5988 defined @samp{*_DEPENDENCIES} explicitly for an unrelated reason, then
5989 you have to add these variables manually.
5991 These variables are usually used to build a portability library that
5992 is linked with all the programs of the project. We now review a
5993 sample setup. First, @file{configure.ac} contains some checks that
5994 affect either @code{LIBOBJS} or @code{ALLOCA}.
5999 AC_CONFIG_LIBOBJ_DIR([lib])
6001 AC_FUNC_MALLOC dnl May add malloc.$(OBJEXT) to LIBOBJS
6002 AC_FUNC_MEMCMP dnl May add memcmp.$(OBJEXT) to LIBOBJS
6003 AC_REPLACE_FUNCS([strdup]) dnl May add strdup.$(OBJEXT) to LIBOBJS
6004 AC_FUNC_ALLOCA dnl May add alloca.$(OBJEXT) to ALLOCA
6013 @acindex AC_CONFIG_LIBOBJ_DIR
6015 The @code{AC_CONFIG_LIBOBJ_DIR} tells Autoconf that the source files
6016 of these object files are to be found in the @file{lib/} directory.
6017 Automake can also use this information, otherwise it expects the
6018 source files are to be in the directory where the @samp{$(LIBOBJS)}
6019 and @samp{$(ALLOCA)} variables are used.
6021 The @file{lib/} directory should therefore contain @file{malloc.c},
6022 @file{memcmp.c}, @file{strdup.c}, @file{alloca.c}. Here is its
6028 noinst_LIBRARIES = libcompat.a
6029 libcompat_a_SOURCES =
6030 libcompat_a_LIBADD = $(LIBOBJS) $(ALLOCA)
6033 The library can have any name, of course, and anyway it is not going
6034 to be installed: it just holds the replacement versions of the missing
6035 or broken functions so we can later link them in. Many projects
6036 also include extra functions, specific to the project, in that
6037 library: they are simply added on the @code{_SOURCES} line.
6039 @cindex Empty libraries and @samp{$(LIBOBJS)}
6040 @cindex @samp{$(LIBOBJS)} and empty libraries
6041 There is a small trap here, though: @samp{$(LIBOBJS)} and
6042 @samp{$(ALLOCA)} might be empty, and building an empty library is not
6043 portable. You should ensure that there is always something to put in
6044 @file{libcompat.a}. Most projects will also add some utility
6045 functions in that directory, and list them in
6046 @code{libcompat_a_SOURCES}, so in practice @file{libcompat.a} cannot
6049 Finally here is how this library could be used from the @file{src/}
6055 # Link all programs in this directory with libcompat.a
6056 LDADD = ../lib/libcompat.a
6058 bin_PROGRAMS = tool1 tool2 @dots{}
6059 tool1_SOURCES = @dots{}
6060 tool2_SOURCES = @dots{}
6063 When option @option{subdir-objects} is not used, as in the above
6064 example, the variables @samp{$(LIBOBJS)} or @samp{$(ALLOCA)} can only
6065 be used in the directory where their sources lie. E.g., here it would
6066 be wrong to use @samp{$(LIBOBJS)} or @samp{$(ALLOCA)} in
6067 @file{src/Makefile.am}. However if both @option{subdir-objects} and
6068 @code{AC_CONFIG_LIBOBJ_DIR} are used, it is OK to use these variables
6069 in other directories. For instance @file{src/Makefile.am} could be
6075 AUTOMAKE_OPTIONS = subdir-objects
6076 LDADD = $(LIBOBJS) $(ALLOCA)
6078 bin_PROGRAMS = tool1 tool2 @dots{}
6079 tool1_SOURCES = @dots{}
6080 tool2_SOURCES = @dots{}
6083 Because @samp{$(LIBOBJS)} and @samp{$(ALLOCA)} contain object
6084 file names that end with @samp{.$(OBJEXT)}, they are not suitable for
6085 Libtool libraries (where the expected object extension is @file{.lo}):
6086 @code{LTLIBOBJS} and @code{LTALLOCA} should be used instead.
6088 @code{LTLIBOBJS} is defined automatically by Autoconf and should not
6089 be defined by hand (as in the past), however at the time of writing
6090 @code{LTALLOCA} still needs to be defined from @code{ALLOCA} manually.
6091 @xref{AC_LIBOBJ vs LIBOBJS, , @code{AC_LIBOBJ} vs.@: @code{LIBOBJS},
6092 autoconf, The Autoconf Manual}.
6095 @node Program Variables
6096 @section Variables used when building a program
6098 Occasionally it is useful to know which @file{Makefile} variables
6099 Automake uses for compilations, and in which order (@pxref{Flag
6100 Variables Ordering}); for instance, you might need to do your own
6101 compilation in some special cases.
6103 Some variables are inherited from Autoconf; these are @code{CC},
6104 @code{CFLAGS}, @code{CPPFLAGS}, @code{DEFS}, @code{LDFLAGS}, and
6113 There are some additional variables that Automake defines on its own:
6117 The contents of this variable are passed to every compilation that invokes
6118 the C preprocessor; it is a list of arguments to the preprocessor. For
6119 instance, @option{-I} and @option{-D} options should be listed here.
6121 Automake already provides some @option{-I} options automatically, in a
6122 separate variable that is also passed to every compilation that invokes
6123 the C preprocessor. In particular it generates @samp{-I.},
6124 @samp{-I$(srcdir)}, and a @option{-I} pointing to the directory holding
6125 @file{config.h} (if you've used @code{AC_CONFIG_HEADERS} or
6126 @code{AM_CONFIG_HEADER}). You can disable the default @option{-I}
6127 options using the @option{nostdinc} option.
6129 When a file to be included is generated during the build and not part
6130 of a distribution tarball, its location is under @code{$(builddir)},
6131 not under @code{$(srcdir)}. This matters especially for packages that
6132 use header files placed in sub-directories and want to allow builds
6133 outside the source tree (@pxref{VPATH Builds}). In that case we
6134 recommend to use a pair of @option{-I} options, such as, e.g.,
6135 @samp{-Isome/subdir -I$(srcdir)/some/subdir} or
6136 @samp{-I$(top_builddir)/some/subdir -I$(top_srcdir)/some/subdir}.
6137 Note that the reference to the build tree should come before the
6138 reference to the source tree, so that accidentally leftover generated
6139 files in the source directory are ignored.
6141 @code{AM_CPPFLAGS} is ignored in preference to a per-executable (or
6142 per-library) @code{_CPPFLAGS} variable if it is defined.
6145 This does the same job as @code{AM_CPPFLAGS} (or any per-target
6146 @code{_CPPFLAGS} variable if it is used). It is an older name for the
6147 same functionality. This variable is deprecated; we suggest using
6148 @code{AM_CPPFLAGS} and per-target @code{_CPPFLAGS} instead.
6151 This is the variable the @file{Makefile.am} author can use to pass
6152 in additional C compiler flags. It is more fully documented elsewhere.
6153 In some situations, this is not used, in preference to the
6154 per-executable (or per-library) @code{_CFLAGS}.
6157 This is the command used to actually compile a C source file. The
6158 file name is appended to form the complete command line.
6161 This is the variable the @file{Makefile.am} author can use to pass
6162 in additional linker flags. In some situations, this is not used, in
6163 preference to the per-executable (or per-library) @code{_LDFLAGS}.
6166 This is the command used to actually link a C program. It already
6167 includes @samp{-o $@@} and the usual variable references (for instance,
6168 @code{CFLAGS}); it takes as ``arguments'' the names of the object files
6169 and libraries to link in. This variable is not used when the linker is
6170 overridden with a per-target @code{_LINK} variable or per-target flags
6171 cause Automake to define such a @code{_LINK} variable.
6176 @section Yacc and Lex support
6178 Automake has somewhat idiosyncratic support for Yacc and Lex.
6180 Automake assumes that the @file{.c} file generated by @command{yacc}
6181 (or @command{lex}) should be named using the basename of the input
6182 file. That is, for a yacc source file @file{foo.y}, Automake will
6183 cause the intermediate file to be named @file{foo.c} (as opposed to
6184 @file{y.tab.c}, which is more traditional).
6186 The extension of a yacc source file is used to determine the extension
6187 of the resulting C or C++ file. Files with the extension @file{.y}
6188 will be turned into @file{.c} files; likewise, @file{.yy} will become
6189 @file{.cc}; @file{.y++}, @file{c++}; @file{.yxx}, @file{.cxx}; and
6190 @file{.ypp}, @file{.cpp}.
6192 Likewise, lex source files can be used to generate C or C++; the
6193 extensions @file{.l}, @file{.ll}, @file{.l++}, @file{.lxx}, and
6194 @file{.lpp} are recognized.
6196 You should never explicitly mention the intermediate (C or C++) file
6197 in any @code{SOURCES} variable; only list the source file.
6199 The intermediate files generated by @command{yacc} (or @command{lex})
6200 will be included in any distribution that is made. That way the user
6201 doesn't need to have @command{yacc} or @command{lex}.
6203 If a @command{yacc} source file is seen, then your @file{configure.ac} must
6204 define the variable @code{YACC}. This is most easily done by invoking
6205 the macro @code{AC_PROG_YACC} (@pxref{Particular Programs, , Particular
6206 Program Checks, autoconf, The Autoconf Manual}).
6210 When @code{yacc} is invoked, it is passed @code{AM_YFLAGS} and
6211 @code{YFLAGS}. The latter is a user variable and the former is
6212 intended for the @file{Makefile.am} author.
6214 @code{AM_YFLAGS} is usually used to pass the @option{-d} option to
6215 @command{yacc}. Automake knows what this means and will automatically
6216 adjust its rules to update and distribute the header file built by
6217 @samp{yacc -d}@footnote{Please note that @command{automake} recognizes
6218 @option{-d} in @code{AM_YFLAGS} only if it is not clustered with other
6219 options; for example, it won't be recognized if @code{AM_YFLAGS} is
6220 @option{-dt}, but it will be if @code{AM_YFLAGS} is @option{-d -t} or
6222 What Automake cannot guess, though, is where this
6223 header will be used: it is up to you to ensure the header gets built
6224 before it is first used. Typically this is necessary in order for
6225 dependency tracking to work when the header is included by another
6226 file. The common solution is listing the header file in
6227 @code{BUILT_SOURCES} (@pxref{Sources}) as follows.
6230 BUILT_SOURCES = parser.h
6233 foo_SOURCES = @dots{} parser.y @dots{}
6236 If a @command{lex} source file is seen, then your @file{configure.ac}
6237 must define the variable @code{LEX}. You can use @code{AC_PROG_LEX}
6238 to do this (@pxref{Particular Programs, , Particular Program Checks,
6239 autoconf, The Autoconf Manual}), but using @code{AM_PROG_LEX} macro
6240 (@pxref{Macros}) is recommended.
6244 When @command{lex} is invoked, it is passed @code{AM_LFLAGS} and
6245 @code{LFLAGS}. The latter is a user variable and the former is
6246 intended for the @file{Makefile.am} author.
6248 When @code{AM_MAINTAINER_MODE} (@pxref{maintainer-mode}) is used, the
6249 rebuild rule for distributed Yacc and Lex sources are only used when
6250 @code{maintainer-mode} is enabled, or when the files have been erased.
6252 @cindex @command{ylwrap}
6253 @cindex @command{yacc}, multiple parsers
6254 @cindex Multiple @command{yacc} parsers
6255 @cindex Multiple @command{lex} lexers
6256 @cindex @command{lex}, multiple lexers
6258 When @command{lex} or @command{yacc} sources are used, @code{automake
6259 -i} automatically installs an auxiliary program called
6260 @command{ylwrap} in your package (@pxref{Auxiliary Programs}). This
6261 program is used by the build rules to rename the output of these
6262 tools, and makes it possible to include multiple @command{yacc} (or
6263 @command{lex}) source files in a single directory. (This is necessary
6264 because yacc's output file name is fixed, and a parallel make could
6265 conceivably invoke more than one instance of @command{yacc}
6268 For @command{yacc}, simply managing locking is insufficient. The output of
6269 @command{yacc} always uses the same symbol names internally, so it isn't
6270 possible to link two @command{yacc} parsers into the same executable.
6272 We recommend using the following renaming hack used in @command{gdb}:
6274 #define yymaxdepth c_maxdepth
6275 #define yyparse c_parse
6277 #define yyerror c_error
6278 #define yylval c_lval
6279 #define yychar c_char
6280 #define yydebug c_debug
6281 #define yypact c_pact
6288 #define yyexca c_exca
6289 #define yyerrflag c_errflag
6290 #define yynerrs c_nerrs
6294 #define yy_yys c_yys
6295 #define yystate c_state
6298 #define yy_yyv c_yyv
6300 #define yylloc c_lloc
6301 #define yyreds c_reds
6302 #define yytoks c_toks
6303 #define yylhs c_yylhs
6304 #define yylen c_yylen
6305 #define yydefred c_yydefred
6306 #define yydgoto c_yydgoto
6307 #define yysindex c_yysindex
6308 #define yyrindex c_yyrindex
6309 #define yygindex c_yygindex
6310 #define yytable c_yytable
6311 #define yycheck c_yycheck
6312 #define yyname c_yyname
6313 #define yyrule c_yyrule
6316 For each define, replace the @samp{c_} prefix with whatever you like.
6317 These defines work for @command{bison}, @command{byacc}, and
6318 traditional @code{yacc}s. If you find a parser generator that uses a
6319 symbol not covered here, please report the new name so it can be added
6324 @section C++ Support
6327 @cindex Support for C++
6329 Automake includes full support for C++.
6331 Any package including C++ code must define the output variable
6332 @code{CXX} in @file{configure.ac}; the simplest way to do this is to use
6333 the @code{AC_PROG_CXX} macro (@pxref{Particular Programs, , Particular
6334 Program Checks, autoconf, The Autoconf Manual}).
6336 A few additional variables are defined when a C++ source file is seen:
6340 The name of the C++ compiler.
6343 Any flags to pass to the C++ compiler.
6346 The maintainer's variant of @code{CXXFLAGS}.
6349 The command used to actually compile a C++ source file. The file name
6350 is appended to form the complete command line.
6353 The command used to actually link a C++ program.
6357 @node Objective C Support
6358 @section Objective C Support
6360 @cindex Objective C support
6361 @cindex Support for Objective C
6363 Automake includes some support for Objective C.
6365 Any package including Objective C code must define the output variable
6366 @code{OBJC} in @file{configure.ac}; the simplest way to do this is to use
6367 the @code{AC_PROG_OBJC} macro (@pxref{Particular Programs, , Particular
6368 Program Checks, autoconf, The Autoconf Manual}).
6370 A few additional variables are defined when an Objective C source file
6375 The name of the Objective C compiler.
6378 Any flags to pass to the Objective C compiler.
6381 The maintainer's variant of @code{OBJCFLAGS}.
6384 The command used to actually compile an Objective C source file. The
6385 file name is appended to form the complete command line.
6388 The command used to actually link an Objective C program.
6392 @node Unified Parallel C Support
6393 @section Unified Parallel C Support
6395 @cindex Unified Parallel C support
6396 @cindex Support for Unified Parallel C
6398 Automake includes some support for Unified Parallel C.
6400 Any package including Unified Parallel C code must define the output
6401 variable @code{UPC} in @file{configure.ac}; the simplest way to do
6402 this is to use the @code{AM_PROG_UPC} macro (@pxref{Public Macros}).
6404 A few additional variables are defined when a Unified Parallel C
6405 source file is seen:
6409 The name of the Unified Parallel C compiler.
6412 Any flags to pass to the Unified Parallel C compiler.
6415 The maintainer's variant of @code{UPCFLAGS}.
6418 The command used to actually compile a Unified Parallel C source file.
6419 The file name is appended to form the complete command line.
6422 The command used to actually link a Unified Parallel C program.
6426 @node Assembly Support
6427 @section Assembly Support
6429 Automake includes some support for assembly code. There are two forms
6430 of assembler files: normal (@file{*.s}) and preprocessed by @code{CPP}
6431 (@file{*.S} or @file{*.sx}).
6436 @vindex AM_CCASFLAGS
6438 The variable @code{CCAS} holds the name of the compiler used to build
6439 assembly code. This compiler must work a bit like a C compiler; in
6440 particular it must accept @option{-c} and @option{-o}. The values of
6441 @code{CCASFLAGS} and @code{AM_CCASFLAGS} (or its per-target
6442 definition) is passed to the compilation. For preprocessed files,
6443 @code{DEFS}, @code{DEFAULT_INCLUDES}, @code{INCLUDES}, @code{CPPFLAGS}
6444 and @code{AM_CPPFLAGS} are also used.
6446 The autoconf macro @code{AM_PROG_AS} will define @code{CCAS} and
6447 @code{CCASFLAGS} for you (unless they are already set, it simply sets
6448 @code{CCAS} to the C compiler and @code{CCASFLAGS} to the C compiler
6449 flags), but you are free to define these variables by other means.
6451 Only the suffixes @file{.s}, @file{.S}, and @file{.sx} are recognized by
6452 @command{automake} as being files containing assembly code.
6455 @node Fortran 77 Support
6456 @comment node-name, next, previous, up
6457 @section Fortran 77 Support
6459 @cindex Fortran 77 support
6460 @cindex Support for Fortran 77
6462 Automake includes full support for Fortran 77.
6464 Any package including Fortran 77 code must define the output variable
6465 @code{F77} in @file{configure.ac}; the simplest way to do this is to use
6466 the @code{AC_PROG_F77} macro (@pxref{Particular Programs, , Particular
6467 Program Checks, autoconf, The Autoconf Manual}).
6469 A few additional variables are defined when a Fortran 77 source file is
6475 The name of the Fortran 77 compiler.
6478 Any flags to pass to the Fortran 77 compiler.
6481 The maintainer's variant of @code{FFLAGS}.
6484 Any flags to pass to the Ratfor compiler.
6487 The maintainer's variant of @code{RFLAGS}.
6490 The command used to actually compile a Fortran 77 source file. The file
6491 name is appended to form the complete command line.
6494 The command used to actually link a pure Fortran 77 program or shared
6499 Automake can handle preprocessing Fortran 77 and Ratfor source files in
6500 addition to compiling them@footnote{Much, if not most, of the
6501 information in the following sections pertaining to preprocessing
6502 Fortran 77 programs was taken almost verbatim from @ref{Catalogue of
6503 Rules, , Catalogue of Rules, make, The GNU Make Manual}.}. Automake
6504 also contains some support for creating programs and shared libraries
6505 that are a mixture of Fortran 77 and other languages (@pxref{Mixing
6506 Fortran 77 With C and C++}).
6508 These issues are covered in the following sections.
6511 * Preprocessing Fortran 77:: Preprocessing Fortran 77 sources
6512 * Compiling Fortran 77 Files:: Compiling Fortran 77 sources
6513 * Mixing Fortran 77 With C and C++:: Mixing Fortran 77 With C and C++
6517 @node Preprocessing Fortran 77
6518 @comment node-name, next, previous, up
6519 @subsection Preprocessing Fortran 77
6521 @cindex Preprocessing Fortran 77
6522 @cindex Fortran 77, Preprocessing
6523 @cindex Ratfor programs
6525 @file{N.f} is made automatically from @file{N.F} or @file{N.r}. This
6526 rule runs just the preprocessor to convert a preprocessable Fortran 77
6527 or Ratfor source file into a strict Fortran 77 source file. The precise
6528 command used is as follows:
6533 @code{$(F77) -F $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS)@*
6534 $(AM_FFLAGS) $(FFLAGS)}
6537 @code{$(F77) -F $(AM_FFLAGS) $(FFLAGS) $(AM_RFLAGS) $(RFLAGS)}
6542 @node Compiling Fortran 77 Files
6543 @comment node-name, next, previous, up
6544 @subsection Compiling Fortran 77 Files
6546 @file{N.o} is made automatically from @file{N.f}, @file{N.F} or
6547 @file{N.r} by running the Fortran 77 compiler. The precise command used
6553 @code{$(F77) -c $(AM_FFLAGS) $(FFLAGS)}
6556 @code{$(F77) -c $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS)@*
6557 $(AM_FFLAGS) $(FFLAGS)}
6560 @code{$(F77) -c $(AM_FFLAGS) $(FFLAGS) $(AM_RFLAGS) $(RFLAGS)}
6565 @node Mixing Fortran 77 With C and C++
6566 @comment node-name, next, previous, up
6567 @subsection Mixing Fortran 77 With C and C++
6569 @cindex Fortran 77, mixing with C and C++
6570 @cindex Mixing Fortran 77 with C and C++
6571 @cindex Linking Fortran 77 with C and C++
6573 @cindex Mixing Fortran 77 with C and/or C++
6575 Automake currently provides @emph{limited} support for creating programs
6576 and shared libraries that are a mixture of Fortran 77 and C and/or C++.
6577 However, there are many other issues related to mixing Fortran 77 with
6578 other languages that are @emph{not} (currently) handled by Automake, but
6579 that are handled by other packages@footnote{For example,
6580 @uref{http://www-zeus.desy.de/~burow/cfortran/, the cfortran package}
6581 addresses all of these inter-language issues, and runs under nearly all
6582 Fortran 77, C and C++ compilers on nearly all platforms. However,
6583 @command{cfortran} is not yet Free Software, but it will be in the next
6586 Automake can help in two ways:
6590 Automatic selection of the linker depending on which combinations of
6594 Automatic selection of the appropriate linker flags (e.g., @option{-L} and
6595 @option{-l}) to pass to the automatically selected linker in order to link
6596 in the appropriate Fortran 77 intrinsic and run-time libraries.
6598 @cindex @code{FLIBS}, defined
6600 These extra Fortran 77 linker flags are supplied in the output variable
6601 @code{FLIBS} by the @code{AC_F77_LIBRARY_LDFLAGS} Autoconf macro
6602 supplied with newer versions of Autoconf (Autoconf version 2.13 and
6603 later). @xref{Fortran Compiler, , Fortran Compiler Characteristics,
6604 autoconf, The Autoconf Manual}.
6607 If Automake detects that a program or shared library (as mentioned in
6608 some @code{_PROGRAMS} or @code{_LTLIBRARIES} primary) contains source
6609 code that is a mixture of Fortran 77 and C and/or C++, then it requires
6610 that the macro @code{AC_F77_LIBRARY_LDFLAGS} be called in
6611 @file{configure.ac}, and that either @code{$(FLIBS)}
6612 appear in the appropriate @code{_LDADD} (for programs) or @code{_LIBADD}
6613 (for shared libraries) variables. It is the responsibility of the
6614 person writing the @file{Makefile.am} to make sure that @samp{$(FLIBS)}
6615 appears in the appropriate @code{_LDADD} or
6616 @code{_LIBADD} variable.
6618 @cindex Mixed language example
6619 @cindex Example, mixed language
6621 For example, consider the following @file{Makefile.am}:
6625 foo_SOURCES = main.cc foo.f
6626 foo_LDADD = libfoo.la $(FLIBS)
6628 pkglib_LTLIBRARIES = libfoo.la
6629 libfoo_la_SOURCES = bar.f baz.c zardoz.cc
6630 libfoo_la_LIBADD = $(FLIBS)
6633 In this case, Automake will insist that @code{AC_F77_LIBRARY_LDFLAGS}
6634 is mentioned in @file{configure.ac}. Also, if @samp{$(FLIBS)} hadn't
6635 been mentioned in @code{foo_LDADD} and @code{libfoo_la_LIBADD}, then
6636 Automake would have issued a warning.
6639 * How the Linker is Chosen:: Automatic linker selection
6642 @node How the Linker is Chosen
6643 @comment node-name, next, previous, up
6644 @subsubsection How the Linker is Chosen
6646 @cindex Automatic linker selection
6647 @cindex Selecting the linker automatically
6649 When a program or library mixes several languages, Automake choose the
6650 linker according to the following priorities. (The names in
6651 parentheses are the variables containing the link command.)
6656 Native Java (@code{GCJLINK})
6659 C++ (@code{CXXLINK})
6662 Fortran 77 (@code{F77LINK})
6665 Fortran (@code{FCLINK})
6668 Objective C (@code{OBJCLINK})
6671 Unified Parallel C (@code{UPCLINK})
6677 For example, if Fortran 77, C and C++ source code is compiled
6678 into a program, then the C++ linker will be used. In this case, if the
6679 C or Fortran 77 linkers required any special libraries that weren't
6680 included by the C++ linker, then they must be manually added to an
6681 @code{_LDADD} or @code{_LIBADD} variable by the user writing the
6684 Automake only looks at the file names listed in @file{_SOURCES}
6685 variables to choose the linker, and defaults to the C linker.
6686 Sometimes this is inconvenient because you are linking against a
6687 library written in another language and would like to set the linker
6688 more appropriately. @xref{Libtool Convenience Libraries}, for a
6689 trick with @code{nodist_EXTRA_@dots{}_SOURCES}.
6691 A per-target @code{_LINK} variable will override the above selection.
6692 Per-target link flags will cause Automake to write a per-target
6693 @code{_LINK} variable according to the language chosen as above.
6696 @node Fortran 9x Support
6697 @comment node-name, next, previous, up
6698 @section Fortran 9x Support
6700 @cindex Fortran 9x support
6701 @cindex Support for Fortran 9x
6703 Automake includes support for Fortran 9x.
6705 Any package including Fortran 9x code must define the output variable
6706 @code{FC} in @file{configure.ac}; the simplest way to do this is to use
6707 the @code{AC_PROG_FC} macro (@pxref{Particular Programs, , Particular
6708 Program Checks, autoconf, The Autoconf Manual}).
6710 A few additional variables are defined when a Fortran 9x source file is
6716 The name of the Fortran 9x compiler.
6719 Any flags to pass to the Fortran 9x compiler.
6722 The maintainer's variant of @code{FCFLAGS}.
6725 The command used to actually compile a Fortran 9x source file. The file
6726 name is appended to form the complete command line.
6729 The command used to actually link a pure Fortran 9x program or shared
6735 * Compiling Fortran 9x Files:: Compiling Fortran 9x sources
6738 @node Compiling Fortran 9x Files
6739 @comment node-name, next, previous, up
6740 @subsection Compiling Fortran 9x Files
6742 @file{@var{file}.o} is made automatically from @file{@var{file}.f90},
6743 @file{@var{file}.f95}, @file{@var{file}.f03}, or @file{@var{file}.f08}
6744 by running the Fortran 9x compiler. The precise command used
6750 @code{$(FC) $(AM_FCFLAGS) $(FCFLAGS) -c $(FCFLAGS_f90) $<}
6753 @code{$(FC) $(AM_FCFLAGS) $(FCFLAGS) -c $(FCFLAGS_f95) $<}
6756 @code{$(FC) $(AM_FCFLAGS) $(FCFLAGS) -c $(FCFLAGS_f03) $<}
6759 @code{$(FC) $(AM_FCFLAGS) $(FCFLAGS) -c $(FCFLAGS_f08) $<}
6763 @node Java Support with gcj
6764 @comment node-name, next, previous, up
6765 @section Compiling Java sources using gcj
6767 @cindex Java support with gcj
6768 @cindex Support for Java with gcj
6769 @cindex Java to native code, compilation
6770 @cindex Compilation of Java to native code
6772 Automake includes support for natively compiled Java, using @command{gcj},
6773 the Java front end to the GNU Compiler Collection (rudimentary support
6774 for compiling Java to bytecode using the @command{javac} compiler is
6775 also present, @emph{albeit deprecated}; @pxref{Java}).
6777 Any package including Java code to be compiled must define the output
6778 variable @code{GCJ} in @file{configure.ac}; the variable @code{GCJFLAGS}
6779 must also be defined somehow (either in @file{configure.ac} or
6780 @file{Makefile.am}). The simplest way to do this is to use the
6781 @code{AM_PROG_GCJ} macro.
6785 By default, programs including Java source files are linked with
6788 As always, the contents of @code{AM_GCJFLAGS} are passed to every
6789 compilation invoking @command{gcj} (in its role as an ahead-of-time
6790 compiler, when invoking it to create @file{.class} files,
6791 @code{AM_JAVACFLAGS} is used instead). If it is necessary to pass
6792 options to @command{gcj} from @file{Makefile.am}, this variable, and not
6793 the user variable @code{GCJFLAGS}, should be used.
6797 @command{gcj} can be used to compile @file{.java}, @file{.class},
6798 @file{.zip}, or @file{.jar} files.
6800 When linking, @command{gcj} requires that the main class be specified
6801 using the @option{--main=} option. The easiest way to do this is to use
6802 the @code{_LDFLAGS} variable for the program.
6806 @comment node-name, next, previous, up
6807 @section Vala Support
6809 @cindex Vala Support
6810 @cindex Support for Vala
6812 Automake provides initial support for Vala
6813 (@uref{http://www.vala-project.org/}).
6814 This requires valac version 0.7.0 or later, and currently requires
6815 the user to use GNU @command{make}.
6818 foo_SOURCES = foo.vala bar.vala zardoc.c
6821 Any @file{.vala} file listed in a @code{_SOURCES} variable will be
6822 compiled into C code by the Vala compiler. The generated @file{.c} files are
6823 distributed. The end user does not need to have a Vala compiler installed.
6825 Automake ships with an Autoconf macro called @code{AM_PROG_VALAC}
6826 that will locate the Vala compiler and optionally check its version
6829 @defmac AM_PROG_VALAC (@ovar{minimum-version})
6830 Try to find a Vala compiler in @env{PATH}. If it is found, the variable
6831 @code{VALAC} is set. Optionally a minimum release number of the compiler
6835 AM_PROG_VALAC([0.7.0])
6839 There are a few variables that are used when compiling Vala sources:
6843 Path to the Vala compiler.
6846 Additional arguments for the Vala compiler.
6849 The maintainer's variant of @code{VALAFLAGS}.
6852 lib_LTLIBRARIES = libfoo.la
6853 libfoo_la_SOURCES = foo.vala
6857 Note that currently, you cannot use per-target @code{*_VALAFLAGS}
6858 (@pxref{Renamed Objects}) to produce different C files from one Vala
6862 @node Support for Other Languages
6863 @comment node-name, next, previous, up
6864 @section Support for Other Languages
6866 Automake currently only includes full support for C, C++ (@pxref{C++
6867 Support}), Objective C (@pxref{Objective C Support}), Fortran 77
6868 (@pxref{Fortran 77 Support}), Fortran 9x (@pxref{Fortran 9x Support}),
6869 and Java (@pxref{Java Support with gcj}). There is only rudimentary
6870 support for other languages, support for which will be improved based
6873 Some limited support for adding your own languages is available via the
6874 suffix rule handling (@pxref{Suffixes}).
6878 @section Automatic de-ANSI-fication (deprecated, soon to be removed)
6880 @cindex de-ANSI-fication, defined
6882 @emph{The features described in this section are deprecated; you must
6883 not use any of them in new code, and remove their use from older but
6884 still maintained code: they will be withdrawn in the next major
6887 When the C language was standardized in 1989, there was a long
6888 transition period where package developers needed to worry about
6889 porting to older systems that did not support ANSI C by default.
6890 These older systems are no longer in practical use and are no longer
6891 supported by their original suppliers, so developers need not worry
6892 about this problem any more.
6894 Automake allows you to write packages that are portable to K&R C by
6895 @dfn{de-ANSI-fying} each source file before the actual compilation takes
6898 @vindex AUTOMAKE_OPTIONS
6901 If the @file{Makefile.am} variable @code{AUTOMAKE_OPTIONS}
6902 (@pxref{Options}) contains the option @option{ansi2knr} then code to
6903 handle de-ANSI-fication is inserted into the generated
6906 This causes each C source file in the directory to be treated as ANSI C@.
6907 If an ANSI C compiler is available, it is used. If no ANSI C compiler
6908 is available, the @command{ansi2knr} program is used to convert the source
6909 files into K&R C, which is then compiled.
6911 The @command{ansi2knr} program is simple-minded. It assumes the source
6912 code will be formatted in a particular way; see the @command{ansi2knr} man
6915 @acindex AM_C_PROTOTYPES
6916 Support for the obsolete de-ANSI-fication feature
6917 requires the source files @file{ansi2knr.c}
6918 and @file{ansi2knr.1} to be in the same package as the ANSI C source;
6919 these files are distributed with Automake. Also, the package
6920 @file{configure.ac} must call the macro @code{AM_C_PROTOTYPES}
6923 Automake also handles finding the @command{ansi2knr} support files in some
6924 other directory in the current package. This is done by prepending the
6925 relative path to the appropriate directory to the @command{ansi2knr}
6926 option. For instance, suppose the package has ANSI C code in the
6927 @file{src} and @file{lib} subdirectories. The files @file{ansi2knr.c} and
6928 @file{ansi2knr.1} appear in @file{lib}. Then this could appear in
6929 @file{src/Makefile.am}:
6932 AUTOMAKE_OPTIONS = ../lib/ansi2knr
6935 If no directory prefix is given, the files are assumed to be in the
6938 Note that automatic de-ANSI-fication will not work when the package is
6939 being built for a different host architecture. That is because
6940 @command{automake} currently has no way to build @command{ansi2knr}
6941 for the build machine.
6943 @c FIXME: this paragraph might be better moved to an `upgrading' section.
6944 @cindex @code{LTLIBOBJS} and @code{ansi2knr}
6945 @cindex @code{LIBOBJS} and @code{ansi2knr}
6946 @cindex @code{ansi2knr} and @code{LTLIBOBJS}
6947 @cindex @code{ansi2knr} and @code{LIBOBJS}
6948 Using @code{LIBOBJS} with source de-ANSI-fication used to require
6949 hand-crafted code in @file{configure} to append @samp{$U} to basenames
6950 in @code{LIBOBJS}. This is no longer true today. Starting with version
6951 2.54, Autoconf takes care of rewriting @code{LIBOBJS} and
6952 @code{LTLIBOBJS}. (@pxref{AC_LIBOBJ vs LIBOBJS, , @code{AC_LIBOBJ}
6953 vs.@: @code{LIBOBJS}, autoconf, The Autoconf Manual})
6956 @section Automatic dependency tracking
6958 As a developer it is often painful to continually update the
6959 @file{Makefile.am} whenever the include-file dependencies change in a
6960 project. Automake supplies a way to automatically track dependency
6961 changes (@pxref{Dependency Tracking}).
6963 @cindex Dependency tracking
6964 @cindex Automatic dependency tracking
6966 Automake always uses complete dependencies for a compilation,
6967 including system headers. Automake's model is that dependency
6968 computation should be a side effect of the build. To this end,
6969 dependencies are computed by running all compilations through a
6970 special wrapper program called @command{depcomp}. @command{depcomp}
6971 understands how to coax many different C and C++ compilers into
6972 generating dependency information in the format it requires.
6973 @samp{automake -a} will install @command{depcomp} into your source
6974 tree for you. If @command{depcomp} can't figure out how to properly
6975 invoke your compiler, dependency tracking will simply be disabled for
6978 @cindex @command{depcomp}
6980 Experience with earlier versions of Automake (@pxref{Dependency
6981 Tracking Evolution}) taught us that it is not reliable to generate
6982 dependencies only on the maintainer's system, as configurations vary
6983 too much. So instead Automake implements dependency tracking at build
6986 Automatic dependency tracking can be suppressed by putting
6987 @option{no-dependencies} in the variable @code{AUTOMAKE_OPTIONS}, or
6988 passing @option{no-dependencies} as an argument to @code{AM_INIT_AUTOMAKE}
6989 (this should be the preferred way). Or, you can invoke @command{automake}
6990 with the @option{-i} option. Dependency tracking is enabled by default.
6992 @vindex AUTOMAKE_OPTIONS
6993 @opindex no-dependencies
6995 The person building your package also can choose to disable dependency
6996 tracking by configuring with @option{--disable-dependency-tracking}.
6998 @cindex Disabling dependency tracking
6999 @cindex Dependency tracking, disabling
7003 @section Support for executable extensions
7005 @cindex Executable extension
7006 @cindex Extension, executable
7009 On some platforms, such as Windows, executables are expected to have an
7010 extension such as @file{.exe}. On these platforms, some compilers (GCC
7011 among them) will automatically generate @file{foo.exe} when asked to
7012 generate @file{foo}.
7014 Automake provides mostly-transparent support for this. Unfortunately
7015 @emph{mostly} doesn't yet mean @emph{fully}. Until the English
7016 dictionary is revised, you will have to assist Automake if your package
7017 must support those platforms.
7019 One thing you must be aware of is that, internally, Automake rewrites
7020 something like this:
7023 bin_PROGRAMS = liver
7029 bin_PROGRAMS = liver$(EXEEXT)
7032 The targets Automake generates are likewise given the @samp{$(EXEEXT)}
7035 The variables @code{TESTS} and @code{XFAIL_TESTS} (@pxref{Simple Tests})
7036 are also rewritten if they contain filenames that have been declared as
7037 programs in the same @file{Makefile}. (This is mostly useful when some
7038 programs from @code{check_PROGRAMS} are listed in @code{TESTS}.)
7040 However, Automake cannot apply this rewriting to @command{configure}
7041 substitutions. This means that if you are conditionally building a
7042 program using such a substitution, then your @file{configure.ac} must
7043 take care to add @samp{$(EXEEXT)} when constructing the output variable.
7045 With Autoconf 2.13 and earlier, you must explicitly use @code{AC_EXEEXT}
7046 to get this support. With Autoconf 2.50, @code{AC_EXEEXT} is run
7047 automatically if you configure a compiler (say, through
7050 Sometimes maintainers like to write an explicit link rule for their
7051 program. Without executable extension support, this is easy---you
7052 simply write a rule whose target is the name of the program. However,
7053 when executable extension support is enabled, you must instead add the
7054 @samp{$(EXEEXT)} suffix.
7056 Unfortunately, due to the change in Autoconf 2.50, this means you must
7057 always add this extension. However, this is a problem for maintainers
7058 who know their package will never run on a platform that has
7059 executable extensions. For those maintainers, the @option{no-exeext}
7060 option (@pxref{Options}) will disable this feature. This works in a
7061 fairly ugly way; if @option{no-exeext} is seen, then the presence of a
7062 rule for a target named @code{foo} in @file{Makefile.am} will override
7063 an @command{automake}-generated rule for @samp{foo$(EXEEXT)}. Without
7064 the @option{no-exeext} option, this use will give a diagnostic.
7068 @chapter Other Derived Objects
7070 Automake can handle derived objects that are not C programs. Sometimes
7071 the support for actually building such objects must be explicitly
7072 supplied, but Automake will still automatically handle installation and
7076 * Scripts:: Executable scripts
7077 * Headers:: Header files
7078 * Data:: Architecture-independent data files
7079 * Sources:: Derived sources
7084 @section Executable Scripts
7086 @cindex @code{_SCRIPTS} primary, defined
7087 @cindex @code{SCRIPTS} primary, defined
7088 @cindex Primary variable, @code{SCRIPTS}
7090 @cindex Installing scripts
7092 It is possible to define and install programs that are scripts. Such
7093 programs are listed using the @code{SCRIPTS} primary name. When the
7094 script is distributed in its final, installable form, the
7095 @file{Makefile} usually looks as follows:
7099 # Install my_script in $(bindir) and distribute it.
7100 dist_bin_SCRIPTS = my_script
7103 Scripts are not distributed by default; as we have just seen, those
7104 that should be distributed can be specified using a @code{dist_}
7105 prefix as with other primaries.
7107 @cindex @code{SCRIPTS}, installation directories
7109 @vindex sbin_SCRIPTS
7110 @vindex libexec_SCRIPTS
7111 @vindex pkgdata_SCRIPTS
7112 @vindex noinst_SCRIPTS
7113 @vindex check_SCRIPTS
7115 Scripts can be installed in @code{bindir}, @code{sbindir},
7116 @code{libexecdir}, or @code{pkgdatadir}.
7118 Scripts that need not be installed can be listed in
7119 @code{noinst_SCRIPTS}, and among them, those which are needed only by
7120 @samp{make check} should go in @code{check_SCRIPTS}.
7122 When a script needs to be built, the @file{Makefile.am} should include
7123 the appropriate rules. For instance the @command{automake} program
7124 itself is a Perl script that is generated from @file{automake.in}.
7125 Here is how this is handled:
7128 bin_SCRIPTS = automake
7129 CLEANFILES = $(bin_SCRIPTS)
7130 EXTRA_DIST = automake.in
7132 do_subst = sed -e 's,[@@]datadir[@@],$(datadir),g' \
7133 -e 's,[@@]PERL[@@],$(PERL),g' \
7134 -e 's,[@@]PACKAGE[@@],$(PACKAGE),g' \
7135 -e 's,[@@]VERSION[@@],$(VERSION),g' \
7138 automake: automake.in Makefile
7139 $(do_subst) < $(srcdir)/automake.in > automake
7143 Such scripts for which a build rule has been supplied need to be
7144 deleted explicitly using @code{CLEANFILES} (@pxref{Clean}), and their
7145 sources have to be distributed, usually with @code{EXTRA_DIST}
7146 (@pxref{Basics of Distribution}).
7148 Another common way to build scripts is to process them from
7149 @file{configure} with @code{AC_CONFIG_FILES}. In this situation
7150 Automake knows which files should be cleaned and distributed, and what
7151 the rebuild rules should look like.
7153 For instance if @file{configure.ac} contains
7156 AC_CONFIG_FILES([src/my_script], [chmod +x src/my_script])
7160 to build @file{src/my_script} from @file{src/my_script.in}, then a
7161 @file{src/Makefile.am} to install this script in @code{$(bindir)} can
7165 bin_SCRIPTS = my_script
7166 CLEANFILES = $(bin_SCRIPTS)
7170 There is no need for @code{EXTRA_DIST} or any build rule: Automake
7171 infers them from @code{AC_CONFIG_FILES} (@pxref{Requirements}).
7172 @code{CLEANFILES} is still useful, because by default Automake will
7173 clean targets of @code{AC_CONFIG_FILES} in @code{distclean}, not
7176 Although this looks simpler, building scripts this way has one
7177 drawback: directory variables such as @code{$(datadir)} are not fully
7178 expanded and may refer to other directory variables.
7181 @section Header files
7183 @cindex @code{_HEADERS} primary, defined
7184 @cindex @code{HEADERS} primary, defined
7185 @cindex Primary variable, @code{HEADERS}
7187 @vindex noinst_HEADERS
7188 @cindex @code{HEADERS}, installation directories
7189 @cindex Installing headers
7190 @vindex include_HEADERS
7191 @vindex oldinclude_HEADERS
7192 @vindex pkginclude_HEADERS
7195 Header files that must be installed are specified by the
7196 @code{HEADERS} family of variables. Headers can be installed in
7197 @code{includedir}, @code{oldincludedir}, @code{pkgincludedir} or any
7198 other directory you may have defined (@pxref{Uniform}). For instance,
7201 include_HEADERS = foo.h bar/bar.h
7205 will install the two files as @file{$(includedir)/foo.h} and
7206 @file{$(includedir)/bar.h}.
7208 The @code{nobase_} prefix is also supported,
7211 nobase_include_HEADERS = foo.h bar/bar.h
7215 will install the two files as @file{$(includedir)/foo.h} and
7216 @file{$(includedir)/bar/bar.h} (@pxref{Alternative}).
7218 @vindex noinst_HEADERS
7219 Usually, only header files that accompany installed libraries need to
7220 be installed. Headers used by programs or convenience libraries are
7221 not installed. The @code{noinst_HEADERS} variable can be used for
7222 such headers. However when the header actually belongs to a single
7223 convenience library or program, we recommend listing it in the
7224 program's or library's @code{_SOURCES} variable (@pxref{Program
7225 Sources}) instead of in @code{noinst_HEADERS}. This is clearer for
7226 the @file{Makefile.am} reader. @code{noinst_HEADERS} would be the
7227 right variable to use in a directory containing only headers and no
7228 associated library or program.
7230 All header files must be listed somewhere; in a @code{_SOURCES}
7231 variable or in a @code{_HEADERS} variable. Missing ones will not
7232 appear in the distribution.
7234 For header files that are built and must not be distributed, use the
7235 @code{nodist_} prefix as in @code{nodist_include_HEADERS} or
7236 @code{nodist_prog_SOURCES}. If these generated headers are needed
7237 during the build, you must also ensure they exist before they are
7238 used (@pxref{Sources}).
7242 @section Architecture-independent data files
7244 @cindex @code{_DATA} primary, defined
7245 @cindex @code{DATA} primary, defined
7246 @cindex Primary variable, @code{DATA}
7249 Automake supports the installation of miscellaneous data files using the
7250 @code{DATA} family of variables.
7254 @vindex sysconf_DATA
7255 @vindex sharedstate_DATA
7256 @vindex localstate_DATA
7257 @vindex pkgdata_DATA
7259 Such data can be installed in the directories @code{datadir},
7260 @code{sysconfdir}, @code{sharedstatedir}, @code{localstatedir}, or
7263 By default, data files are @emph{not} included in a distribution. Of
7264 course, you can use the @code{dist_} prefix to change this on a
7267 Here is how Automake declares its auxiliary data files:
7270 dist_pkgdata_DATA = clean-kr.am clean.am @dots{}
7275 @section Built Sources
7277 Because Automake's automatic dependency tracking works as a side-effect
7278 of compilation (@pxref{Dependencies}) there is a bootstrap issue: a
7279 target should not be compiled before its dependencies are made, but
7280 these dependencies are unknown until the target is first compiled.
7282 Ordinarily this is not a problem, because dependencies are distributed
7283 sources: they preexist and do not need to be built. Suppose that
7284 @file{foo.c} includes @file{foo.h}. When it first compiles
7285 @file{foo.o}, @command{make} only knows that @file{foo.o} depends on
7286 @file{foo.c}. As a side-effect of this compilation @command{depcomp}
7287 records the @file{foo.h} dependency so that following invocations of
7288 @command{make} will honor it. In these conditions, it's clear there is
7289 no problem: either @file{foo.o} doesn't exist and has to be built
7290 (regardless of the dependencies), or accurate dependencies exist and
7291 they can be used to decide whether @file{foo.o} should be rebuilt.
7293 It's a different story if @file{foo.h} doesn't exist by the first
7294 @command{make} run. For instance, there might be a rule to build
7295 @file{foo.h}. This time @file{file.o}'s build will fail because the
7296 compiler can't find @file{foo.h}. @command{make} failed to trigger the
7297 rule to build @file{foo.h} first by lack of dependency information.
7299 @vindex BUILT_SOURCES
7300 @cindex @code{BUILT_SOURCES}, defined
7302 The @code{BUILT_SOURCES} variable is a workaround for this problem. A
7303 source file listed in @code{BUILT_SOURCES} is made on @samp{make all}
7304 or @samp{make check} (or even @samp{make install}) before other
7305 targets are processed. However, such a source file is not
7306 @emph{compiled} unless explicitly requested by mentioning it in some
7307 other @code{_SOURCES} variable.
7309 So, to conclude our introductory example, we could use
7310 @samp{BUILT_SOURCES = foo.h} to ensure @file{foo.h} gets built before
7311 any other target (including @file{foo.o}) during @samp{make all} or
7314 @code{BUILT_SOURCES} is actually a bit of a misnomer, as any file which
7315 must be created early in the build process can be listed in this
7316 variable. Moreover, all built sources do not necessarily have to be
7317 listed in @code{BUILT_SOURCES}. For instance, a generated @file{.c} file
7318 doesn't need to appear in @code{BUILT_SOURCES} (unless it is included by
7319 another source), because it's a known dependency of the associated
7322 It might be important to emphasize that @code{BUILT_SOURCES} is
7323 honored only by @samp{make all}, @samp{make check} and @samp{make
7324 install}. This means you cannot build a specific target (e.g.,
7325 @samp{make foo}) in a clean tree if it depends on a built source.
7326 However it will succeed if you have run @samp{make all} earlier,
7327 because accurate dependencies are already available.
7329 The next section illustrates and discusses the handling of built sources
7333 * Built Sources Example:: Several ways to handle built sources.
7336 @node Built Sources Example
7337 @subsection Built Sources Example
7339 Suppose that @file{foo.c} includes @file{bindir.h}, which is
7340 installation-dependent and not distributed: it needs to be built. Here
7341 @file{bindir.h} defines the preprocessor macro @code{bindir} to the
7342 value of the @command{make} variable @code{bindir} (inherited from
7345 We suggest several implementations below. It's not meant to be an
7346 exhaustive listing of all ways to handle built sources, but it will give
7347 you a few ideas if you encounter this issue.
7349 @subsubheading First Try
7351 This first implementation will illustrate the bootstrap issue mentioned
7352 in the previous section (@pxref{Sources}).
7354 Here is a tentative @file{Makefile.am}.
7360 nodist_foo_SOURCES = bindir.h
7361 CLEANFILES = bindir.h
7363 echo '#define bindir "$(bindir)"' >$@@
7366 This setup doesn't work, because Automake doesn't know that @file{foo.c}
7367 includes @file{bindir.h}. Remember, automatic dependency tracking works
7368 as a side-effect of compilation, so the dependencies of @file{foo.o} will
7369 be known only after @file{foo.o} has been compiled (@pxref{Dependencies}).
7370 The symptom is as follows.
7374 source='foo.c' object='foo.o' libtool=no \
7375 depfile='.deps/foo.Po' tmpdepfile='.deps/foo.TPo' \
7376 depmode=gcc /bin/sh ./depcomp \
7377 gcc -I. -I. -g -O2 -c `test -f 'foo.c' || echo './'`foo.c
7378 foo.c:2: bindir.h: No such file or directory
7379 make: *** [foo.o] Error 1
7382 In this example @file{bindir.h} is not distributed nor installed, and
7383 it is not even being built on-time. One may wonder if the
7384 @samp{nodist_foo_SOURCES = bindir.h} line has any use at all. This
7385 line simply states that @file{bindir.h} is a source of @code{foo}, so
7386 for instance, it should be inspected while generating tags
7387 (@pxref{Tags}). In other words, it does not help our present problem,
7388 and the build would fail identically without it.
7390 @subsubheading Using @code{BUILT_SOURCES}
7392 A solution is to require @file{bindir.h} to be built before anything
7393 else. This is what @code{BUILT_SOURCES} is meant for (@pxref{Sources}).
7398 nodist_foo_SOURCES = bindir.h
7399 BUILT_SOURCES = bindir.h
7400 CLEANFILES = bindir.h
7402 echo '#define bindir "$(bindir)"' >$@@
7405 See how @file{bindir.h} gets built first:
7409 echo '#define bindir "/usr/local/bin"' >bindir.h
7411 make[1]: Entering directory `/home/adl/tmp'
7412 source='foo.c' object='foo.o' libtool=no \
7413 depfile='.deps/foo.Po' tmpdepfile='.deps/foo.TPo' \
7414 depmode=gcc /bin/sh ./depcomp \
7415 gcc -I. -I. -g -O2 -c `test -f 'foo.c' || echo './'`foo.c
7416 gcc -g -O2 -o foo foo.o
7417 make[1]: Leaving directory `/home/adl/tmp'
7420 However, as said earlier, @code{BUILT_SOURCES} applies only to the
7421 @code{all}, @code{check}, and @code{install} targets. It still fails
7422 if you try to run @samp{make foo} explicitly:
7426 test -z "bindir.h" || rm -f bindir.h
7427 test -z "foo" || rm -f foo
7429 % : > .deps/foo.Po # Suppress previously recorded dependencies
7431 source='foo.c' object='foo.o' libtool=no \
7432 depfile='.deps/foo.Po' tmpdepfile='.deps/foo.TPo' \
7433 depmode=gcc /bin/sh ./depcomp \
7434 gcc -I. -I. -g -O2 -c `test -f 'foo.c' || echo './'`foo.c
7435 foo.c:2: bindir.h: No such file or directory
7436 make: *** [foo.o] Error 1
7439 @subsubheading Recording Dependencies manually
7441 Usually people are happy enough with @code{BUILT_SOURCES} because they
7442 never build targets such as @samp{make foo} before @samp{make all}, as
7443 in the previous example. However if this matters to you, you can
7444 avoid @code{BUILT_SOURCES} and record such dependencies explicitly in
7445 the @file{Makefile.am}.
7450 nodist_foo_SOURCES = bindir.h
7451 foo.$(OBJEXT): bindir.h
7452 CLEANFILES = bindir.h
7454 echo '#define bindir "$(bindir)"' >$@@
7457 You don't have to list @emph{all} the dependencies of @file{foo.o}
7458 explicitly, only those that might need to be built. If a dependency
7459 already exists, it will not hinder the first compilation and will be
7460 recorded by the normal dependency tracking code. (Note that after
7461 this first compilation the dependency tracking code will also have
7462 recorded the dependency between @file{foo.o} and
7463 @file{bindir.h}; so our explicit dependency is really useful to
7464 the first build only.)
7466 Adding explicit dependencies like this can be a bit dangerous if you are
7467 not careful enough. This is due to the way Automake tries not to
7468 overwrite your rules (it assumes you know better than it).
7469 @samp{foo.$(OBJEXT): bindir.h} supersedes any rule Automake may want to
7470 output to build @samp{foo.$(OBJEXT)}. It happens to work in this case
7471 because Automake doesn't have to output any @samp{foo.$(OBJEXT):}
7472 target: it relies on a suffix rule instead (i.e., @samp{.c.$(OBJEXT):}).
7473 Always check the generated @file{Makefile.in} if you do this.
7475 @subsubheading Build @file{bindir.h} from @file{configure}
7477 It's possible to define this preprocessor macro from @file{configure},
7478 either in @file{config.h} (@pxref{Defining Directories, , Defining
7479 Directories, autoconf, The Autoconf Manual}), or by processing a
7480 @file{bindir.h.in} file using @code{AC_CONFIG_FILES}
7481 (@pxref{Configuration Actions, ,Configuration Actions, autoconf, The
7484 At this point it should be clear that building @file{bindir.h} from
7485 @file{configure} works well for this example. @file{bindir.h} will exist
7486 before you build any target, hence will not cause any dependency issue.
7488 The Makefile can be shrunk as follows. We do not even have to mention
7496 However, it's not always possible to build sources from
7497 @file{configure}, especially when these sources are generated by a tool
7498 that needs to be built first.
7500 @subsubheading Build @file{bindir.c}, not @file{bindir.h}.
7502 Another attractive idea is to define @code{bindir} as a variable or
7503 function exported from @file{bindir.o}, and build @file{bindir.c}
7504 instead of @file{bindir.h}.
7507 noinst_PROGRAMS = foo
7508 foo_SOURCES = foo.c bindir.h
7509 nodist_foo_SOURCES = bindir.c
7510 CLEANFILES = bindir.c
7512 echo 'const char bindir[] = "$(bindir)";' >$@@
7515 @file{bindir.h} contains just the variable's declaration and doesn't
7516 need to be built, so it won't cause any trouble. @file{bindir.o} is
7517 always dependent on @file{bindir.c}, so @file{bindir.c} will get built
7520 @subsubheading Which is best?
7522 There is no panacea, of course. Each solution has its merits and
7525 You cannot use @code{BUILT_SOURCES} if the ability to run @samp{make
7526 foo} on a clean tree is important to you.
7528 You won't add explicit dependencies if you are leery of overriding
7529 an Automake rule by mistake.
7531 Building files from @file{./configure} is not always possible, neither
7532 is converting @file{.h} files into @file{.c} files.
7535 @node Other GNU Tools
7536 @chapter Other GNU Tools
7538 Since Automake is primarily intended to generate @file{Makefile.in}s for
7539 use in GNU programs, it tries hard to interoperate with other GNU tools.
7542 * Emacs Lisp:: Emacs Lisp
7545 * Java:: Java bytecode compilation (deprecated)
7553 @cindex @code{_LISP} primary, defined
7554 @cindex @code{LISP} primary, defined
7555 @cindex Primary variable, @code{LISP}
7561 Automake provides some support for Emacs Lisp. The @code{LISP} primary
7562 is used to hold a list of @file{.el} files. Possible prefixes for this
7563 primary are @code{lisp_} and @code{noinst_}. Note that if
7564 @code{lisp_LISP} is defined, then @file{configure.ac} must run
7565 @code{AM_PATH_LISPDIR} (@pxref{Macros}).
7567 @vindex dist_lisp_LISP
7568 @vindex dist_noinst_LISP
7569 Lisp sources are not distributed by default. You can prefix the
7570 @code{LISP} primary with @code{dist_}, as in @code{dist_lisp_LISP} or
7571 @code{dist_noinst_LISP}, to indicate that these files should be
7574 Automake will byte-compile all Emacs Lisp source files using the Emacs
7575 found by @code{AM_PATH_LISPDIR}, if any was found.
7577 Byte-compiled Emacs Lisp files are not portable among all versions of
7578 Emacs, so it makes sense to turn this off if you expect sites to have
7579 more than one version of Emacs installed. Furthermore, many packages
7580 don't actually benefit from byte-compilation. Still, we recommend
7581 that you byte-compile your Emacs Lisp sources. It is probably better
7582 for sites with strange setups to cope for themselves than to make the
7583 installation less nice for everybody else.
7585 There are two ways to avoid byte-compiling. Historically, we have
7586 recommended the following construct.
7589 lisp_LISP = file1.el file2.el
7594 @code{ELCFILES} is an internal Automake variable that normally lists
7595 all @file{.elc} files that must be byte-compiled. Automake defines
7596 @code{ELCFILES} automatically from @code{lisp_LISP}. Emptying this
7597 variable explicitly prevents byte-compilation.
7599 Since Automake 1.8, we now recommend using @code{lisp_DATA} instead:
7601 @c Keep in sync with primary-prefix-couples-documented-valid.test.
7603 lisp_DATA = file1.el file2.el
7606 Note that these two constructs are not equivalent. @code{_LISP} will
7607 not install a file if Emacs is not installed, while @code{_DATA} will
7608 always install its files.
7613 @cindex GNU Gettext support
7614 @cindex Gettext support
7615 @cindex Support for GNU Gettext
7617 If @code{AM_GNU_GETTEXT} is seen in @file{configure.ac}, then Automake
7618 turns on support for GNU gettext, a message catalog system for
7619 internationalization
7620 (@pxref{Top, , Introduction, gettext, GNU gettext utilities}).
7622 The @code{gettext} support in Automake requires the addition of one or
7623 two subdirectories to the package: @file{po} and possibly also @file{intl}.
7624 The latter is needed if @code{AM_GNU_GETTEXT} is not invoked with the
7625 @samp{external} argument, or if @code{AM_GNU_GETTEXT_INTL_SUBDIR} is used.
7626 Automake ensures that these directories exist and are mentioned in
7632 Automake provides support for GNU Libtool (@pxref{Top, , Introduction,
7633 libtool, The Libtool Manual}) with the @code{LTLIBRARIES} primary.
7634 @xref{A Shared Library}.
7638 @section Java bytecode compilation (deprecated)
7640 @cindex @code{_JAVA} primary, defined
7641 @cindex @code{JAVA} primary, defined
7642 @cindex Primary variable, @code{JAVA}
7643 @cindex Java to bytecode, compilation
7644 @cindex Compilation of Java to bytecode
7646 Automake provides some minimal support for Java bytecode compilation with
7647 the @code{JAVA} primary (in addition to the support for compiling Java to
7648 native machine code; @pxref{Java Support with gcj}). Note however that
7649 @emph{the interface and most features described here are deprecated}; the
7650 next automake release will strive to provide a better and cleaner
7651 interface, which however @emph{won't be backward-compatible}; the present
7652 interface will probably be removed altogether in future automake releases
7653 (1.13 or later), so don't use it in new code.
7655 Any @file{.java} files listed in a @code{_JAVA} variable will be
7656 compiled with @code{JAVAC} at build time. By default, @file{.java}
7657 files are not included in the distribution, you should use the
7658 @code{dist_} prefix to distribute them.
7660 Here is a typical setup for distributing @file{.java} files and
7661 installing the @file{.class} files resulting from their compilation.
7663 @c Keep in sync with primary-prefix-couples-documented-valid.test.
7665 javadir = $(datadir)/java
7666 dist_java_JAVA = a.java b.java @dots{}
7669 @cindex @code{JAVA} restrictions
7670 @cindex Restrictions for @code{JAVA}
7672 Currently Automake enforces the restriction that only one @code{_JAVA}
7673 primary can be used in a given @file{Makefile.am}. The reason for this
7674 restriction is that, in general, it isn't possible to know which
7675 @file{.class} files were generated from which @file{.java} files, so
7676 it would be impossible to know which files to install where. For
7677 instance, a @file{.java} file can define multiple classes; the resulting
7678 @file{.class} file names cannot be predicted without parsing the
7681 There are a few variables that are used when compiling Java sources:
7685 The name of the Java compiler. This defaults to @samp{javac}.
7688 The flags to pass to the compiler. This is considered to be a user
7689 variable (@pxref{User Variables}).
7692 More flags to pass to the Java compiler. This, and not
7693 @code{JAVACFLAGS}, should be used when it is necessary to put Java
7694 compiler flags into @file{Makefile.am}.
7697 The value of this variable is passed to the @option{-d} option to
7698 @code{javac}. It defaults to @samp{$(top_builddir)}.
7701 This variable is a shell expression that is used to set the
7702 @env{CLASSPATH} environment variable on the @code{javac} command line.
7703 (In the future we will probably handle class path setting differently.)
7710 @cindex @code{_PYTHON} primary, defined
7711 @cindex @code{PYTHON} primary, defined
7712 @cindex Primary variable, @code{PYTHON}
7715 Automake provides support for Python compilation with the
7716 @code{PYTHON} primary. A typical setup is to call
7717 @code{AM_PATH_PYTHON} in @file{configure.ac} and use a line like the
7718 following in @file{Makefile.am}:
7721 python_PYTHON = tree.py leave.py
7724 Any files listed in a @code{_PYTHON} variable will be byte-compiled
7725 with @command{py-compile} at install time. @command{py-compile}
7726 actually creates both standard (@file{.pyc}) and optimized
7727 (@file{.pyo}) byte-compiled versions of the source files. Note that
7728 because byte-compilation occurs at install time, any files listed in
7729 @code{noinst_PYTHON} will not be compiled. Python source files are
7730 included in the distribution by default, prepend @code{nodist_} (as in
7731 @code{nodist_python_PYTHON}) to omit them.
7733 Automake ships with an Autoconf macro called @code{AM_PATH_PYTHON}
7734 that will determine some Python-related directory variables (see
7735 below). If you have called @code{AM_PATH_PYTHON} from
7736 @file{configure.ac}, then you may use the variables
7737 @c Keep in sync with primary-prefix-couples-documented-valid.test.
7738 @code{python_PYTHON} or @code{pkgpython_PYTHON} to list Python source
7739 files in your @file{Makefile.am}, depending on where you want your files
7740 installed (see the definitions of @code{pythondir} and
7741 @code{pkgpythondir} below).
7743 @defmac AM_PATH_PYTHON (@ovar{version}, @ovar{action-if-found},
7744 @ovar{action-if-not-found})
7746 Search for a Python interpreter on the system. This macro takes three
7747 optional arguments. The first argument, if present, is the minimum
7748 version of Python required for this package: @code{AM_PATH_PYTHON}
7749 will skip any Python interpreter that is older than @var{version}.
7750 If an interpreter is found and satisfies @var{version}, then
7751 @var{action-if-found} is run. Otherwise, @var{action-if-not-found} is
7754 If @var{action-if-not-found} is not specified, as in the following
7755 example, the default is to abort @command{configure}.
7758 AM_PATH_PYTHON([2.2])
7762 This is fine when Python is an absolute requirement for the package.
7763 If Python >= 2.5 was only @emph{optional} to the package,
7764 @code{AM_PATH_PYTHON} could be called as follows.
7767 AM_PATH_PYTHON([2.5],, [:])
7770 If the @env{PYTHON} variable is set when @code{AM_PATH_PYTHON} is
7771 called, then that will be the only Python interpreter that is tried.
7773 @code{AM_PATH_PYTHON} creates the following output variables based on
7774 the Python installation found during configuration.
7779 The name of the Python executable, or @samp{:} if no suitable
7780 interpreter could be found.
7782 Assuming @var{action-if-not-found} is used (otherwise @file{./configure}
7783 will abort if Python is absent), the value of @code{PYTHON} can be used
7784 to setup a conditional in order to disable the relevant part of a build
7788 AM_PATH_PYTHON(,, [:])
7789 AM_CONDITIONAL([HAVE_PYTHON], [test "$PYTHON" != :])
7792 @item PYTHON_VERSION
7793 The Python version number, in the form @var{major}.@var{minor}
7794 (e.g., @samp{2.5}). This is currently the value of
7795 @samp{sys.version[:3]}.
7798 The string @samp{$@{prefix@}}. This term may be used in future work
7799 that needs the contents of Python's @samp{sys.prefix}, but general
7800 consensus is to always use the value from @command{configure}.
7802 @item PYTHON_EXEC_PREFIX
7803 The string @samp{$@{exec_prefix@}}. This term may be used in future work
7804 that needs the contents of Python's @samp{sys.exec_prefix}, but general
7805 consensus is to always use the value from @command{configure}.
7807 @item PYTHON_PLATFORM
7808 The canonical name used by Python to describe the operating system, as
7809 given by @samp{sys.platform}. This value is sometimes needed when
7810 building Python extensions.
7813 The directory name for the @file{site-packages} subdirectory of the
7814 standard Python install tree.
7817 This is the directory under @code{pythondir} that is named after the
7818 package. That is, it is @samp{$(pythondir)/$(PACKAGE)}. It is provided
7822 This is the directory where Python extension modules (shared libraries)
7823 should be installed. An extension module written in C could be declared
7824 as follows to Automake:
7826 @c Keep in sync with primary-prefix-couples-documented-valid.test.
7828 pyexec_LTLIBRARIES = quaternion.la
7829 quaternion_la_SOURCES = quaternion.c support.c support.h
7830 quaternion_la_LDFLAGS = -avoid-version -module
7834 This is a convenience variable that is defined as
7835 @samp{$(pyexecdir)/$(PACKAGE)}.
7838 All these directory variables have values that start with either
7839 @samp{$@{prefix@}} or @samp{$@{exec_prefix@}} unexpanded. This works
7840 fine in @file{Makefiles}, but it makes these variables hard to use in
7841 @file{configure}. This is mandated by the GNU coding standards, so
7842 that the user can run @samp{make prefix=/foo install}. The Autoconf
7843 manual has a section with more details on this topic
7844 (@pxref{Installation Directory Variables, , Installation Directory
7845 Variables, autoconf, The Autoconf Manual}). See also @ref{Hard-Coded
7850 @chapter Building documentation
7852 Currently Automake provides support for Texinfo and man pages.
7856 * Man Pages:: Man pages
7863 @cindex @code{_TEXINFOS} primary, defined
7864 @cindex @code{TEXINFOS} primary, defined
7865 @cindex Primary variable, @code{TEXINFOS}
7866 @cindex HTML output using Texinfo
7867 @cindex PDF output using Texinfo
7868 @cindex PS output using Texinfo
7869 @cindex DVI output using Texinfo
7871 @vindex info_TEXINFOS
7873 If the current directory contains Texinfo source, you must declare it
7874 with the @code{TEXINFOS} primary. Generally Texinfo files are converted
7875 into info, and thus the @code{info_TEXINFOS} variable is most commonly used
7876 here. Any Texinfo source file must end in the @file{.texi},
7877 @file{.txi}, or @file{.texinfo} extension. We recommend @file{.texi}
7880 Automake generates rules to build @file{.info}, @file{.dvi},
7881 @file{.ps}, @file{.pdf} and @file{.html} files from your Texinfo
7882 sources. Following the GNU Coding Standards, only the @file{.info}
7883 files are built by @samp{make all} and installed by @samp{make
7884 install} (unless you use @option{no-installinfo}, see below).
7885 Furthermore, @file{.info} files are automatically distributed so that
7886 Texinfo is not a prerequisite for installing your package.
7892 @trindex install-dvi
7893 @trindex install-html
7894 @trindex install-pdf
7896 Other documentation formats can be built on request by @samp{make
7897 dvi}, @samp{make ps}, @samp{make pdf} and @samp{make html}, and they
7898 can be installed with @samp{make install-dvi}, @samp{make install-ps},
7899 @samp{make install-pdf} and @samp{make install-html} explicitly.
7900 @samp{make uninstall} will remove everything: the Texinfo
7901 documentation installed by default as well as all the above optional
7904 All these targets can be extended using @samp{-local} rules
7905 (@pxref{Extending}).
7907 @cindex Texinfo flag, @code{VERSION}
7908 @cindex Texinfo flag, @code{UPDATED}
7909 @cindex Texinfo flag, @code{EDITION}
7910 @cindex Texinfo flag, @code{UPDATED-MONTH}
7912 @cindex @code{VERSION} Texinfo flag
7913 @cindex @code{UPDATED} Texinfo flag
7914 @cindex @code{EDITION} Texinfo flag
7915 @cindex @code{UPDATED-MONTH} Texinfo flag
7917 @cindex @file{mdate-sh}
7919 If the @file{.texi} file @code{@@include}s @file{version.texi}, then
7920 that file will be automatically generated. The file @file{version.texi}
7921 defines four Texinfo flag you can reference using
7922 @code{@@value@{EDITION@}}, @code{@@value@{VERSION@}},
7923 @code{@@value@{UPDATED@}}, and @code{@@value@{UPDATED-MONTH@}}.
7928 Both of these flags hold the version number of your program. They are
7929 kept separate for clarity.
7932 This holds the date the primary @file{.texi} file was last modified.
7935 This holds the name of the month in which the primary @file{.texi} file
7939 The @file{version.texi} support requires the @command{mdate-sh}
7940 script; this script is supplied with Automake and automatically
7941 included when @command{automake} is invoked with the
7942 @option{--add-missing} option.
7944 If you have multiple Texinfo files, and you want to use the
7945 @file{version.texi} feature, then you have to have a separate version
7946 file for each Texinfo file. Automake will treat any include in a
7947 Texinfo file that matches @file{vers*.texi} just as an automatically
7948 generated version file.
7950 Sometimes an info file actually depends on more than one @file{.texi}
7951 file. For instance, in GNU Hello, @file{hello.texi} includes the file
7952 @file{fdl.texi}. You can tell Automake about these dependencies using
7953 the @code{@var{texi}_TEXINFOS} variable. Here is how GNU Hello does it:
7958 info_TEXINFOS = hello.texi
7959 hello_TEXINFOS = fdl.texi
7962 @cindex @file{texinfo.tex}
7964 By default, Automake requires the file @file{texinfo.tex} to appear in
7965 the same directory as the @file{Makefile.am} file that lists the
7966 @file{.texi} files. If you used @code{AC_CONFIG_AUX_DIR} in
7967 @file{configure.ac} (@pxref{Input, , Finding `configure' Input,
7968 autoconf, The Autoconf Manual}), then @file{texinfo.tex} is looked for
7969 there. In both cases, @command{automake} then supplies @file{texinfo.tex} if
7970 @option{--add-missing} is given, and takes care of its distribution.
7971 However, if you set the @code{TEXINFO_TEX} variable (see below),
7972 it overrides the location of the file and turns off its installation
7973 into the source as well as its distribution.
7975 The option @option{no-texinfo.tex} can be used to eliminate the
7976 requirement for the file @file{texinfo.tex}. Use of the variable
7977 @code{TEXINFO_TEX} is preferable, however, because that allows the
7978 @code{dvi}, @code{ps}, and @code{pdf} targets to still work.
7980 @cindex Option, @code{no-installinfo}
7981 @cindex Target, @code{install-info}
7982 @cindex @code{install-info} target
7983 @cindex @code{no-installinfo} option
7985 @opindex no-installinfo
7986 @trindex install-info
7988 Automake generates an @code{install-info} rule; some people apparently
7989 use this. By default, info pages are installed by @samp{make
7990 install}, so running @code{make install-info} is pointless. This can
7991 be prevented via the @code{no-installinfo} option. In this case,
7992 @file{.info} files are not installed by default, and user must
7993 request this explicitly using @samp{make install-info}.
7995 The following variables are used by the Texinfo build rules.
7999 The name of the program invoked to build @file{.info} files. This
8000 variable is defined by Automake. If the @command{makeinfo} program is
8001 found on the system then it will be used by default; otherwise
8002 @command{missing} will be used instead.
8005 The command invoked to build @file{.html} files. Automake
8006 defines this to @samp{$(MAKEINFO) --html}.
8009 User flags passed to each invocation of @samp{$(MAKEINFO)} and
8010 @samp{$(MAKEINFOHTML)}. This user variable (@pxref{User Variables}) is
8011 not expected to be defined in any @file{Makefile}; it can be used by
8012 users to pass extra flags to suit their needs.
8014 @item AM_MAKEINFOFLAGS
8015 @itemx AM_MAKEINFOHTMLFLAGS
8016 Maintainer flags passed to each @command{makeinfo} invocation. Unlike
8017 @code{MAKEINFOFLAGS}, these variables are meant to be defined by
8018 maintainers in @file{Makefile.am}. @samp{$(AM_MAKEINFOFLAGS)} is
8019 passed to @code{makeinfo} when building @file{.info} files; and
8020 @samp{$(AM_MAKEINFOHTMLFLAGS)} is used when building @file{.html}
8023 @c Keep in sync with txinfo21.test.
8024 For instance, the following setting can be used to obtain one single
8025 @file{.html} file per manual, without node separators.
8027 AM_MAKEINFOHTMLFLAGS = --no-headers --no-split
8030 @code{AM_MAKEINFOHTMLFLAGS} defaults to @samp{$(AM_MAKEINFOFLAGS)}.
8031 This means that defining @code{AM_MAKEINFOFLAGS} without defining
8032 @code{AM_MAKEINFOHTMLFLAGS} will impact builds of both @file{.info}
8033 and @file{.html} files.
8036 The name of the command that converts a @file{.texi} file into a
8037 @file{.dvi} file. This defaults to @samp{texi2dvi}, a script that ships
8038 with the Texinfo package.
8041 The name of the command that translates a @file{.texi} file into a
8042 @file{.pdf} file. This defaults to @samp{$(TEXI2DVI) --pdf --batch}.
8045 The name of the command that builds a @file{.ps} file out of a
8046 @file{.dvi} file. This defaults to @samp{dvips}.
8050 If your package has Texinfo files in many directories, you can use the
8051 variable @code{TEXINFO_TEX} to tell Automake where to find the canonical
8052 @file{texinfo.tex} for your package. The value of this variable should
8053 be the relative path from the current @file{Makefile.am} to
8057 TEXINFO_TEX = ../doc/texinfo.tex
8065 @cindex @code{_MANS} primary, defined
8066 @cindex @code{MANS} primary, defined
8067 @cindex Primary variable, @code{MANS}
8071 A package can also include man pages (but see the GNU standards on this
8072 matter, @ref{Man Pages, , , standards, The GNU Coding Standards}.) Man
8073 pages are declared using the @code{MANS} primary. Generally the
8074 @code{man_MANS} variable is used. Man pages are automatically installed in
8075 the correct subdirectory of @code{mandir}, based on the file extension.
8077 File extensions such as @file{.1c} are handled by looking for the valid
8078 part of the extension and using that to determine the correct
8079 subdirectory of @code{mandir}. Valid section names are the digits
8080 @samp{0} through @samp{9}, and the letters @samp{l} and @samp{n}.
8082 Sometimes developers prefer to name a man page something like
8083 @file{foo.man} in the source, and then rename it to have the correct
8084 suffix, for example @file{foo.1}, when installing the file. Automake
8085 also supports this mode. For a valid section named @var{section},
8086 there is a corresponding directory named @samp{man@var{section}dir},
8087 and a corresponding @code{_MANS} variable. Files listed in such a
8088 variable are installed in the indicated section. If the file already
8089 has a valid suffix, then it is installed as-is; otherwise the file
8090 suffix is changed to match the section.
8092 For instance, consider this example:
8094 man1_MANS = rename.man thesame.1 alsothesame.1c
8098 In this case, @file{rename.man} will be renamed to @file{rename.1} when
8099 installed, but the other files will keep their names.
8101 @cindex Target, @code{install-man}
8102 @cindex Option, @option{no-installman}
8103 @cindex @code{install-man} target
8104 @cindex @option{no-installman} option
8105 @opindex no-installman
8106 @trindex install-man
8108 By default, man pages are installed by @samp{make install}. However,
8109 since the GNU project does not require man pages, many maintainers do
8110 not expend effort to keep the man pages up to date. In these cases, the
8111 @option{no-installman} option will prevent the man pages from being
8112 installed by default. The user can still explicitly install them via
8113 @samp{make install-man}.
8115 For fast installation, with many files it is preferable to use
8116 @samp{man@var{section}_MANS} over @samp{man_MANS} as well as files that
8117 do not need to be renamed.
8119 Man pages are not currently considered to be source, because it is not
8120 uncommon for man pages to be automatically generated. Therefore they
8121 are not automatically included in the distribution. However, this can
8122 be changed by use of the @code{dist_} prefix. For instance here is
8123 how to distribute and install the two man pages of GNU @command{cpio}
8124 (which includes both Texinfo documentation and man pages):
8127 dist_man_MANS = cpio.1 mt.1
8130 The @code{nobase_} prefix is meaningless for man pages and is
8134 @cindex @code{notrans_} prefix
8135 @cindex Man page renaming, avoiding
8136 @cindex Avoiding man page renaming
8138 Executables and manpages may be renamed upon installation
8139 (@pxref{Renaming}). For manpages this can be avoided by use of the
8140 @code{notrans_} prefix. For instance, suppose an executable @samp{foo}
8141 allowing to access a library function @samp{foo} from the command line.
8142 The way to avoid renaming of the @file{foo.3} manpage is:
8146 notrans_man_MANS = foo.3
8149 @cindex @code{notrans_} and @code{dist_} or @code{nodist_}
8150 @cindex @code{dist_} and @code{notrans_}
8151 @cindex @code{nodist_} and @code{notrans_}
8153 @samp{notrans_} must be specified first when used in conjunction with
8154 either @samp{dist_} or @samp{nodist_} (@pxref{Fine-grained Distribution
8155 Control}). For instance:
8158 notrans_dist_man3_MANS = bar.3
8162 @chapter What Gets Installed
8164 @cindex Installation support
8165 @cindex @samp{make install} support
8167 Naturally, Automake handles the details of actually installing your
8168 program once it has been built. All files named by the various
8169 primaries are automatically installed in the appropriate places when the
8170 user runs @samp{make install}.
8173 * Basics of Installation:: What gets installed where
8174 * The Two Parts of Install:: Installing data and programs separately
8175 * Extending Installation:: Adding your own rules for installation
8176 * Staged Installs:: Installation in a temporary location
8177 * Install Rules for the User:: Useful additional rules
8180 @node Basics of Installation
8181 @section Basics of Installation
8183 A file named in a primary is installed by copying the built file into
8184 the appropriate directory. The base name of the file is used when
8188 bin_PROGRAMS = hello subdir/goodbye
8191 In this example, both @samp{hello} and @samp{goodbye} will be installed
8192 in @samp{$(bindir)}.
8194 Sometimes it is useful to avoid the basename step at install time. For
8195 instance, you might have a number of header files in subdirectories of
8196 the source tree that are laid out precisely how you want to install
8197 them. In this situation you can use the @code{nobase_} prefix to
8198 suppress the base name step. For example:
8201 nobase_include_HEADERS = stdio.h sys/types.h
8205 will install @file{stdio.h} in @samp{$(includedir)} and @file{types.h}
8206 in @samp{$(includedir)/sys}.
8208 For most file types, Automake will install multiple files at once, while
8209 avoiding command line length issues (@pxref{Length Limitations}). Since
8210 some @command{install} programs will not install the same file twice in
8211 one invocation, you may need to ensure that file lists are unique within
8212 one variable such as @samp{nobase_include_HEADERS} above.
8214 You should not rely on the order in which files listed in one variable
8215 are installed. Likewise, to cater for parallel make, you should not
8216 rely on any particular file installation order even among different
8217 file types (library dependencies are an exception here).
8220 @node The Two Parts of Install
8221 @section The Two Parts of Install
8223 Automake generates separate @code{install-data} and @code{install-exec}
8224 rules, in case the installer is installing on multiple machines that
8225 share directory structure---these targets allow the machine-independent
8226 parts to be installed only once. @code{install-exec} installs
8227 platform-dependent files, and @code{install-data} installs
8228 platform-independent files. The @code{install} target depends on both
8229 of these targets. While Automake tries to automatically segregate
8230 objects into the correct category, the @file{Makefile.am} author is, in
8231 the end, responsible for making sure this is done correctly.
8232 @trindex install-data
8233 @trindex install-exec
8235 @cindex Install, two parts of
8237 Variables using the standard directory prefixes @samp{data},
8238 @samp{info}, @samp{man}, @samp{include}, @samp{oldinclude},
8239 @samp{pkgdata}, or @samp{pkginclude} are installed by
8240 @code{install-data}.
8242 Variables using the standard directory prefixes @samp{bin},
8243 @samp{sbin}, @samp{libexec}, @samp{sysconf}, @samp{localstate},
8244 @samp{lib}, or @samp{pkglib} are installed by @code{install-exec}.
8246 For instance, @code{data_DATA} files are installed by @code{install-data},
8247 while @code{bin_PROGRAMS} files are installed by @code{install-exec}.
8249 Any variable using a user-defined directory prefix with
8250 @samp{exec} in the name (e.g.,
8251 @c Keep in sync with primary-prefix-couples-documented-valid.test.
8252 @code{myexecbin_PROGRAMS}) is installed by @code{install-exec}. All
8253 other user-defined prefixes are installed by @code{install-data}.
8255 @node Extending Installation
8256 @section Extending Installation
8258 It is possible to extend this mechanism by defining an
8259 @code{install-exec-local} or @code{install-data-local} rule. If these
8260 rules exist, they will be run at @samp{make install} time. These
8261 rules can do almost anything; care is required.
8262 @trindex install-exec-local
8263 @trindex install-data-local
8265 Automake also supports two install hooks, @code{install-exec-hook} and
8266 @code{install-data-hook}. These hooks are run after all other install
8267 rules of the appropriate type, exec or data, have completed. So, for
8268 instance, it is possible to perform post-installation modifications
8269 using an install hook. @xref{Extending}, for some examples.
8270 @cindex Install hook
8272 @node Staged Installs
8273 @section Staged Installs
8276 Automake generates support for the @code{DESTDIR} variable in all
8277 install rules. @code{DESTDIR} is used during the @samp{make install}
8278 step to relocate install objects into a staging area. Each object and
8279 path is prefixed with the value of @code{DESTDIR} before being copied
8280 into the install area. Here is an example of typical DESTDIR usage:
8283 mkdir /tmp/staging &&
8284 make DESTDIR=/tmp/staging install
8287 The @command{mkdir} command avoids a security problem if the attacker
8288 creates a symbolic link from @file{/tmp/staging} to a victim area;
8289 then @command{make} places install objects in a directory tree built under
8290 @file{/tmp/staging}. If @file{/gnu/bin/foo} and
8291 @file{/gnu/share/aclocal/foo.m4} are to be installed, the above command
8292 would install @file{/tmp/staging/gnu/bin/foo} and
8293 @file{/tmp/staging/gnu/share/aclocal/foo.m4}.
8295 This feature is commonly used to build install images and packages
8298 Support for @code{DESTDIR} is implemented by coding it directly into
8299 the install rules. If your @file{Makefile.am} uses a local install
8300 rule (e.g., @code{install-exec-local}) or an install hook, then you
8301 must write that code to respect @code{DESTDIR}.
8303 @xref{Makefile Conventions, , , standards, The GNU Coding Standards},
8304 for another usage example.
8306 @node Install Rules for the User
8307 @section Install Rules for the User
8309 Automake also generates rules for targets @code{uninstall},
8310 @code{installdirs}, and @code{install-strip}.
8312 @trindex installdirs
8313 @trindex install-strip
8315 Automake supports @code{uninstall-local} and @code{uninstall-hook}.
8316 There is no notion of separate uninstalls for ``exec'' and ``data'', as
8317 these features would not provide additional functionality.
8319 Note that @code{uninstall} is not meant as a replacement for a real
8324 @chapter What Gets Cleaned
8326 @cindex @samp{make clean} support
8328 The GNU Makefile Standards specify a number of different clean rules.
8329 @xref{Standard Targets, , Standard Targets for Users, standards,
8330 The GNU Coding Standards}.
8332 Generally the files that can be cleaned are determined automatically by
8333 Automake. Of course, Automake also recognizes some variables that can
8334 be defined to specify additional files to clean. These variables are
8335 @code{MOSTLYCLEANFILES}, @code{CLEANFILES}, @code{DISTCLEANFILES}, and
8336 @code{MAINTAINERCLEANFILES}.
8337 @vindex MOSTLYCLEANFILES
8339 @vindex DISTCLEANFILES
8340 @vindex MAINTAINERCLEANFILES
8342 @trindex mostlyclean-local
8343 @trindex clean-local
8344 @trindex distclean-local
8345 @trindex maintainer-clean-local
8346 When cleaning involves more than deleting some hard-coded list of
8347 files, it is also possible to supplement the cleaning rules with your
8348 own commands. Simply define a rule for any of the
8349 @code{mostlyclean-local}, @code{clean-local}, @code{distclean-local},
8350 or @code{maintainer-clean-local} targets (@pxref{Extending}). A common
8351 case is deleting a directory, for instance, a directory created by the
8359 Since @command{make} allows only one set of rules for a given target,
8360 a more extensible way of writing this is to use a separate target
8361 listed as a dependency:
8364 clean-local: clean-local-check
8365 .PHONY: clean-local-check
8370 As the GNU Standards aren't always explicit as to which files should
8371 be removed by which rule, we've adopted a heuristic that we believe
8372 was first formulated by Fran@,{c}ois Pinard:
8376 If @command{make} built it, and it is commonly something that one would
8377 want to rebuild (for instance, a @file{.o} file), then
8378 @code{mostlyclean} should delete it.
8381 Otherwise, if @command{make} built it, then @code{clean} should delete it.
8384 If @command{configure} built it, then @code{distclean} should delete it.
8387 If the maintainer built it (for instance, a @file{.info} file), then
8388 @code{maintainer-clean} should delete it. However
8389 @code{maintainer-clean} should not delete anything that needs to exist
8390 in order to run @samp{./configure && make}.
8393 We recommend that you follow this same set of heuristics in your
8398 @chapter What Goes in a Distribution
8401 * Basics of Distribution:: Files distributed by default
8402 * Fine-grained Distribution Control:: @code{dist_} and @code{nodist_} prefixes
8403 * The dist Hook:: A target for last-minute distribution changes
8404 * Checking the Distribution:: @samp{make distcheck} explained
8405 * The Types of Distributions:: A variety of formats and compression methods
8408 @node Basics of Distribution
8409 @section Basics of Distribution
8411 @cindex @samp{make dist}
8416 The @code{dist} rule in the generated @file{Makefile.in} can be used
8417 to generate a gzipped @code{tar} file and other flavors of archive for
8418 distribution. The file is named based on the @code{PACKAGE} and
8419 @code{VERSION} variables defined by @code{AM_INIT_AUTOMAKE}
8420 (@pxref{Macros}); more precisely the gzipped @code{tar} file is named
8421 @samp{@var{package}-@var{version}.tar.gz}.
8423 You can use the @command{make} variable @code{GZIP_ENV} to control how gzip
8424 is run. The default setting is @option{--best}.
8426 @cindex @code{m4_include}, distribution
8427 @cindex @code{include}, distribution
8430 For the most part, the files to distribute are automatically found by
8431 Automake: all source files are automatically included in a distribution,
8432 as are all @file{Makefile.am} and @file{Makefile.in} files. Automake also
8433 has a built-in list of commonly used files that are automatically
8434 included if they are found in the current directory (either physically,
8435 or as the target of a @file{Makefile.am} rule); this list is printed by
8436 @samp{automake --help}. Note that some files in this list are actually
8437 distributed only if other certain conditions hold (for example,
8438 @c Keep in sync with autodist-config-headers.test.
8439 the @file{config.h.top} and @file{config.h.bot} files are automatically
8440 distributed only if, e.g., @samp{AC_CONFIG_HEADERS([config.h])} is used
8441 in @file{configure.ac}). Also, files that are read by @command{configure}
8442 (i.e.@: the source files corresponding to the files specified in various
8443 Autoconf macros such as @code{AC_CONFIG_FILES} and siblings) are
8444 automatically distributed. Files included in a @file{Makefile.am} (using
8445 @code{include}) or in @file{configure.ac} (using @code{m4_include}), and
8446 helper scripts installed with @samp{automake --add-missing} are also
8450 Still, sometimes there are files that must be distributed, but which
8451 are not covered in the automatic rules. These files should be listed in
8452 the @code{EXTRA_DIST} variable. You can mention files from
8453 subdirectories in @code{EXTRA_DIST}.
8455 You can also mention a directory in @code{EXTRA_DIST}; in this case the
8456 entire directory will be recursively copied into the distribution.
8457 Please note that this will also copy @emph{everything} in the directory,
8458 including, e.g., Subversion's @file{.svn} private directories or CVS/RCS
8459 version control files. We recommend against using this feature.
8462 @vindex DIST_SUBDIRS
8463 If you define @code{SUBDIRS}, Automake will recursively include the
8464 subdirectories in the distribution. If @code{SUBDIRS} is defined
8465 conditionally (@pxref{Conditionals}), Automake will normally include
8466 all directories that could possibly appear in @code{SUBDIRS} in the
8467 distribution. If you need to specify the set of directories
8468 conditionally, you can set the variable @code{DIST_SUBDIRS} to the
8469 exact list of subdirectories to include in the distribution
8470 (@pxref{Conditional Subdirectories}).
8473 @node Fine-grained Distribution Control
8474 @section Fine-grained Distribution Control
8478 Sometimes you need tighter control over what does @emph{not} go into the
8479 distribution; for instance, you might have source files that are
8480 generated and that you do not want to distribute. In this case
8481 Automake gives fine-grained control using the @code{dist} and
8482 @code{nodist} prefixes. Any primary or @code{_SOURCES} variable can be
8483 prefixed with @code{dist_} to add the listed files to the distribution.
8484 Similarly, @code{nodist_} can be used to omit the files from the
8487 As an example, here is how you would cause some data to be distributed
8488 while leaving some source code out of the distribution:
8491 dist_data_DATA = distribute-this
8493 nodist_foo_SOURCES = do-not-distribute.c
8497 @section The dist Hook
8501 Occasionally it is useful to be able to change the distribution before
8502 it is packaged up. If the @code{dist-hook} rule exists, it is run
8503 after the distribution directory is filled, but before the actual tar
8504 (or shar) file is created. One way to use this is for distributing
8505 files in subdirectories for which a new @file{Makefile.am} is overkill:
8509 mkdir $(distdir)/random
8510 cp -p $(srcdir)/random/a1 $(srcdir)/random/a2 $(distdir)/random
8513 Another way to use this is for removing unnecessary files that get
8514 recursively included by specifying a directory in EXTRA_DIST:
8520 rm -rf `find $(distdir)/doc -type d -name .svn`
8525 Two variables that come handy when writing @code{dist-hook} rules are
8526 @samp{$(distdir)} and @samp{$(top_distdir)}.
8528 @samp{$(distdir)} points to the directory where the @code{dist} rule
8529 will copy files from the current directory before creating the
8530 tarball. If you are at the top-level directory, then @samp{distdir =
8531 $(PACKAGE)-$(VERSION)}. When used from subdirectory named
8532 @file{foo/}, then @samp{distdir = ../$(PACKAGE)-$(VERSION)/foo}.
8533 @samp{$(distdir)} can be a relative or absolute path, do not assume
8536 @samp{$(top_distdir)} always points to the root directory of the
8537 distributed tree. At the top-level it's equal to @samp{$(distdir)}.
8538 In the @file{foo/} subdirectory
8539 @samp{top_distdir = ../$(PACKAGE)-$(VERSION)}.
8540 @samp{$(top_distdir)} too can be a relative or absolute path.
8542 Note that when packages are nested using @code{AC_CONFIG_SUBDIRS}
8543 (@pxref{Subpackages}), then @samp{$(distdir)} and
8544 @samp{$(top_distdir)} are relative to the package where @samp{make
8545 dist} was run, not to any sub-packages involved.
8547 @node Checking the Distribution
8548 @section Checking the Distribution
8550 @cindex @samp{make distcheck}
8551 @cindex @samp{make distcleancheck}
8552 @vindex distcleancheck_listfiles
8553 @cindex @samp{make distuninstallcheck}
8554 @vindex distuninstallcheck_listfiles
8557 Automake also generates a @code{distcheck} rule that can be of help to
8558 ensure that a given distribution will actually work. @code{distcheck}
8559 makes a distribution, then tries to do a @code{VPATH} build
8560 (@pxref{VPATH Builds}), run the test suite, and finally make another
8561 tarball to ensure the distribution is self-contained.
8563 @vindex AM_DISTCHECK_CONFIGURE_FLAGS
8564 @vindex DISTCHECK_CONFIGURE_FLAGS
8565 Building the package involves running @samp{./configure}. If you need
8566 to supply additional flags to @command{configure}, define them in the
8567 @code{AM_DISTCHECK_CONFIGURE_FLAGS} variable in your top-level
8568 @file{Makefile.am}. The user can still extend or override the flags
8569 provided there by defining the @code{DISTCHECK_CONFIGURE_FLAGS} variable,
8570 on the command line when invoking @command{make}.
8572 Still, developers are encouraged to strive to make their code buildable
8573 without requiring any special configure option; thus, in general, you
8574 shouldn't define @code{AM_DISTCHECK_CONFIGURE_FLAGS}. However, there
8575 might be few scenarios in which the use of this variable is justified.
8576 GNU @command{m4} offers an example. GNU @command{m4} configures by
8577 default with its experimental and seldom used "changeword" feature
8578 disabled; so in its case it is useful to have @command{make distcheck}
8579 run configure with the @option{--with-changeword} option, to ensure that
8580 the code for changeword support still compiles correctly.
8581 GNU @command{m4} also employs the @code{AM_DISTCHECK_CONFIGURE_FLAGS}
8582 variable to stress-test the use of @option{--program-prefix=g}, since at
8583 one point the @command{m4} build system had a bug where @command{make
8584 installcheck} was wrongly assuming it could blindly test "@command{m4}",
8585 rather than the just-installed "@command{gm4}".
8587 @trindex distcheck-hook
8588 If the @code{distcheck-hook} rule is defined in your top-level
8589 @file{Makefile.am}, then it will be invoked by @code{distcheck} after
8590 the new distribution has been unpacked, but before the unpacked copy
8591 is configured and built. Your @code{distcheck-hook} can do almost
8592 anything, though as always caution is advised. Generally this hook is
8593 used to check for potential distribution errors not caught by the
8594 standard mechanism. Note that @code{distcheck-hook} as well as
8595 @code{AM_DISTCHECK_CONFIGURE_FLAGS} and @code{DISTCHECK_CONFIGURE_FLAGS}
8596 are not honored in a subpackage @file{Makefile.am}, but the flags from
8597 @code{AM_DISTCHECK_CONFIGURE_FLAGS} and @code{DISTCHECK_CONFIGURE_FLAGS}
8598 are passed down to the @command{configure} script of the subpackage.
8600 @trindex distcleancheck
8601 @vindex DISTCLEANFILES
8602 @vindex distcleancheck_listfiles
8603 Speaking of potential distribution errors, @code{distcheck} also
8604 ensures that the @code{distclean} rule actually removes all built
8605 files. This is done by running @samp{make distcleancheck} at the end of
8606 the @code{VPATH} build. By default, @code{distcleancheck} will run
8607 @code{distclean} and then make sure the build tree has been emptied by
8608 running @samp{$(distcleancheck_listfiles)}. Usually this check will
8609 find generated files that you forgot to add to the @code{DISTCLEANFILES}
8610 variable (@pxref{Clean}).
8612 The @code{distcleancheck} behavior should be OK for most packages,
8613 otherwise you have the possibility to override the definition of
8614 either the @code{distcleancheck} rule, or the
8615 @samp{$(distcleancheck_listfiles)} variable. For instance, to disable
8616 @code{distcleancheck} completely, add the following rule to your
8617 top-level @file{Makefile.am}:
8624 If you want @code{distcleancheck} to ignore built files that have not
8625 been cleaned because they are also part of the distribution, add the
8626 following definition instead:
8628 @c Keep in sync with distcleancheck.test.
8630 distcleancheck_listfiles = \
8631 find . -type f -exec sh -c 'test -f $(srcdir)/$$1 || echo $$1' \
8635 The above definition is not the default because it's usually an error if
8636 your Makefiles cause some distributed files to be rebuilt when the user
8637 build the package. (Think about the user missing the tool required to
8638 build the file; or if the required tool is built by your package,
8639 consider the cross-compilation case where it can't be run.) There is
8640 an entry in the FAQ about this (@pxref{distcleancheck}), make sure you
8641 read it before playing with @code{distcleancheck_listfiles}.
8643 @code{distcheck} also checks that the @code{uninstall} rule works
8644 properly, both for ordinary and @code{DESTDIR} builds. It does this
8645 by invoking @samp{make uninstall}, and then it checks the install tree
8646 to see if any files are left over. This check will make sure that you
8647 correctly coded your @code{uninstall}-related rules.
8649 By default, the checking is done by the @code{distuninstallcheck} rule,
8650 and the list of files in the install tree is generated by
8651 @samp{$(distuninstallcheck_listfiles)} (this is a variable whose value is
8652 a shell command to run that prints the list of files to stdout).
8654 Either of these can be overridden to modify the behavior of
8655 @code{distcheck}. For instance, to disable this check completely, you
8663 @node The Types of Distributions
8664 @section The Types of Distributions
8666 Automake generates rules to provide archives of the project for
8667 distributions in various formats. Their targets are:
8670 @item @code{dist-bzip2}
8671 Generate a bzip2 tar archive of the distribution. bzip2 archives are
8672 frequently smaller than gzipped archives.
8675 @item @code{dist-gzip}
8676 Generate a gzip tar archive of the distribution.
8679 @item @code{dist-lzma}
8680 Generate an @samp{lzma} tar archive of the distribution. @command{lzma}
8681 archives are frequently smaller than @command{bzip2}-compressed archives.
8682 The @samp{lzma} format is obsolete, you should use the @samp{xz} format
8686 @item @code{dist-shar}
8687 Generate a shar archive of the distribution.
8690 @item @code{dist-xz}
8691 Generate an @samp{xz} tar archive of the distribution. @command{xz}
8692 archives are frequently smaller than @command{bzip2}-compressed archives.
8693 The @samp{xz} format displaces the obsolete @samp{lzma} format.
8696 @item @code{dist-zip}
8697 Generate a zip archive of the distribution.
8700 @item @code{dist-tarZ}
8701 Generate a compressed tar archive of
8706 The rule @code{dist} (and its historical synonym @code{dist-all}) will
8707 create archives in all the enabled formats, @ref{Options}. By
8708 default, only the @code{dist-gzip} target is hooked to @code{dist}.
8712 @chapter Support for test suites
8715 @cindex @code{make check}
8718 Automake supports three forms of test suites, the first two of which
8722 * Simple Tests:: Listing programs and scripts in @code{TESTS}
8723 * Simple Tests using parallel-tests:: More powerful test driver
8724 * DejaGnu Tests:: Interfacing with the external testing framework
8725 * Install Tests:: Running tests on installed packages
8729 @section Simple Tests
8731 If the variable @code{TESTS} is defined, its value is taken to be a
8732 list of programs or scripts to run in order to do the testing.
8733 Programs needing data files should look for them in @code{srcdir}
8734 (which is both an environment variable and a make variable) so they
8735 work when building in a separate directory (@pxref{Build Directories,
8736 , Build Directories , autoconf, The Autoconf Manual}), and in
8737 particular for the @code{distcheck} rule (@pxref{Checking the
8740 For each of the @code{TESTS}, the result of execution is printed along
8741 with the test name, where @code{PASS} denotes a successful test,
8742 @code{FAIL} denotes a failed test, @code{XFAIL} an expected failure,
8743 @code{XPASS} an unexpected pass for a test that is supposed to fail,
8744 and @code{SKIP} denotes a skipped test.
8746 @cindex Exit status 77, special interpretation
8748 The number of failures will be printed at the end of the run. If a
8749 given test program exits with a status of 77, then its result is ignored
8750 in the final count. This feature allows non-portable tests to be
8751 ignored in environments where they don't make sense.
8753 @vindex AM_COLOR_TESTS
8754 If the Automake option @code{color-tests} is used (@pxref{Options})
8755 and standard output is connected to a capable terminal, then the test
8756 results and the summary are colored appropriately. The user can disable
8757 colored output by setting the @command{make} variable
8758 @samp{AM_COLOR_TESTS=no}, or force colored output even without a connecting
8759 terminal with @samp{AM_COLOR_TESTS=always}.
8761 Note that the semantics of some @command{make} implementations when used
8762 in parallel mode (@pxref{Parallel make,,, autoconf, The Autoconf Manual})
8763 can cause the automatic detection of a connection to a capable terminal
8764 to fail. In that case, you can still resort to the use of
8765 @samp{AM_COLOR_TESTS=always}.
8768 @vindex TESTS_ENVIRONMENT
8769 The variable @code{TESTS_ENVIRONMENT} can be used to set environment
8770 variables for the test run; the environment variable @env{srcdir} is
8771 set in the rule. If all your test programs are scripts, you can also
8772 set @code{TESTS_ENVIRONMENT} to an invocation of the shell (e.g.
8773 @samp{$(SHELL) -x} can be useful for debugging the tests), or any other
8774 interpreter. For instance, the following setup may be used to run tests
8777 @c Keep in sync with tests-environment-backcompat.test.
8779 TESTS_ENVIRONMENT = $(PERL) -Mstrict -w
8780 TESTS = foo.pl bar.pl baz.pl
8783 Note that the @option{parallel-tests} driver provides a more elegant
8784 way to achieve the same effect, freeing the @code{TESTS_ENVIRONMENT}
8785 variable for the user to override (@pxref{Simple Tests using
8789 @cindex Tests, expected failure
8790 @cindex Expected test failure
8793 You may define the variable @code{XFAIL_TESTS} to a list of tests
8794 (usually a subset of @code{TESTS}) that are expected to fail. This will
8795 reverse the result of those tests.
8797 Automake ensures that each file listed in @code{TESTS} is built before
8798 any tests are run; you can list both source and derived programs (or
8799 scripts) in @code{TESTS}; the generated rule will look both in
8800 @code{srcdir} and @file{.}. For instance, you might want to run a C
8801 program as a test. To do this you would list its name in @code{TESTS}
8802 and also in @code{check_PROGRAMS}, and then specify it as you would
8805 Programs listed in @code{check_PROGRAMS} (and @code{check_LIBRARIES},
8806 @code{check_LTLIBRARIES}...) are only built during @code{make check},
8807 not during @code{make all}. You should list there any program needed
8808 by your tests that does not need to be built by @code{make all}. Note
8809 that @code{check_PROGRAMS} are @emph{not} automatically added to
8810 @code{TESTS} because @code{check_PROGRAMS} usually lists programs used
8811 by the tests, not the tests themselves. Of course you can set
8812 @code{TESTS = $(check_PROGRAMS)} if all your programs are test cases.
8815 @node Simple Tests using parallel-tests
8816 @section Simple Tests using @samp{parallel-tests}
8817 @cindex @option{parallel-tests}, Using
8819 The option @option{parallel-tests} (@pxref{Options}) enables a test
8820 suite driver that is mostly compatible to the simple test driver described
8821 in the previous section, but provides a few more features and slightly different
8822 semantics. It features concurrent execution of tests with @code{make -j},
8823 allows to specify inter-test dependencies, lazy reruns of tests that
8824 have not completed in a prior run, summary and verbose output in
8825 @samp{RST} (reStructuredText) and @samp{HTML} format, and hard errors
8826 for exceptional failures. Similar to the simple test driver,
8827 @code{TESTS_ENVIRONMENT}, @code{AM_COLOR_TESTS}, @code{XFAIL_TESTS}, and
8828 the @code{check_*} variables are honored, and the environment variable
8829 @env{srcdir} is set during test execution.
8831 This test driver is still experimental and may undergo changes in order
8832 to satisfy additional portability requirements.
8834 @vindex TEST_SUITE_LOG
8836 The driver operates by defining a set of @command{make} rules to create
8837 a summary log file, @code{TEST_SUITE_LOG}, which defaults to
8838 @file{test-suite.log} and requires a @file{.log} suffix. This file
8839 depends upon log files created for each single test program listed in
8840 @code{TESTS}, which in turn contain all output produced by the
8841 corresponding tests.
8843 @vindex TEST_EXTENSIONS
8845 Each log file is created when the corresponding test has completed.
8846 The set of log files is listed in the read-only variable
8847 @code{TEST_LOGS}, and defaults to @code{TESTS}, with the executable
8848 extension if any (@pxref{EXEEXT}), as well as any suffix listed in
8849 @code{TEST_EXTENSIONS} removed, and @file{.log} appended. Results
8850 are undefined if a test file name ends in several concatenated suffixes.
8851 @code{TEST_EXTENSIONS} defaults to @file{.test}; it can be overridden by
8852 the user, in which case any extension listed in it must be constituted
8853 by a dot, followed by a non-digit alphabetic character, followed by any
8854 number of alphabetic characters.
8855 @c Keep in sync with test-extensions.test.
8856 For example, @samp{.sh}, @samp{.T} and @samp{.t1} are valid extensions,
8857 while @samp{.x-y}, @samp{.6c} and @samp{.t.1} are not.
8859 @vindex _LOG_COMPILE
8860 @vindex _LOG_COMPILER
8863 @vindex LOG_COMPILER
8865 @vindex @var{ext}_LOG_COMPILE
8866 @vindex @var{ext}_LOG_COMPILER
8867 @vindex @var{ext}_LOG_FLAGS
8868 @vindex AM_@var{ext}_LOG_FLAGS
8869 @vindex AM_LOG_FLAGS
8870 For tests that match an extension @code{.@var{ext}} listed in
8871 @code{TEST_EXTENSIONS}, you can provide a test driver using the variable
8872 @code{@var{ext}_LOG_COMPILER} (note the upper-case extension) and pass
8873 options in @code{AM_@var{ext}_LOG_FLAGS} and allow the user to pass
8874 options in @code{@var{ext}_LOG_FLAGS}. It will cause all tests with
8875 this extension to be called with this driver. For all tests without a
8876 registered extension, the variables @code{LOG_COMPILER},
8877 @code{AM_LOG_FLAGS}, and @code{LOG_FLAGS} may be used. For example,
8879 @c Keep in sync with parallel-tests-log-compiler-example.test.
8881 TESTS = foo.pl bar.py baz
8882 TEST_EXTENSIONS = .pl .py
8883 PL_LOG_COMPILER = $(PERL)
8884 AM_PL_LOG_FLAGS = -w
8885 PY_LOG_COMPILER = $(PYTHON)
8886 AM_PY_LOG_FLAGS = -v
8887 LOG_COMPILER = ./wrapper-script
8892 will invoke @samp{$(PERL) -w foo.pl}, @samp{$(PYTHON) -v bar.py},
8893 and @samp{./wrapper-script -d baz} to produce @file{foo.log},
8894 @file{bar.log}, and @file{baz.log}, respectively. The
8895 @samp{TESTS_ENVIRONMENT} variable is still expanded before the driver,
8896 but should be reserved for the user.
8899 As with the simple driver above, by default one status line is printed
8900 per completed test, and a short summary after the suite has completed.
8901 However, standard output and standard error of the test are redirected
8902 to a per-test log file, so that parallel execution does not produce
8903 intermingled output. The output from failed tests is collected in the
8904 @file{test-suite.log} file. If the variable @samp{VERBOSE} is set, this
8905 file is output after the summary. For best results, the tests should be
8906 verbose by default now.
8908 @trindex mostlyclean
8911 @vindex TEST_SUITE_HTML
8912 With @code{make check-html}, the log files may be converted from RST
8913 (reStructuredText, see @uref{http://docutils.sourceforge.net/@/rst.html})
8914 to HTML using @samp{RST2HTML}, which defaults to @command{rst2html} or
8915 @command{rst2html.py}. The variable @samp{TEST_SUITE_HTML} contains the
8916 set of converted log files. The log and HTML files are removed upon
8917 @code{make mostlyclean}.
8919 @vindex DISABLE_HARD_ERRORS
8920 @cindex Exit status 99, special interpretation
8922 Even in the presence of expected failures (see @code{XFAIL_TESTS}), there
8923 may be conditions under which a test outcome needs attention. For
8924 example, with test-driven development, you may write tests for features
8925 that you have not implemented yet, and thus mark these tests as expected
8926 to fail. However, you may still be interested in exceptional conditions,
8927 for example, tests that fail due to a segmentation violation or another
8928 error that is independent of the feature awaiting implementation.
8929 Tests can exit with an exit status of 99 to signal such a @emph{hard
8930 error}. Unless the variable @code{DISABLE_HARD_ERRORS} is set to a
8931 nonempty value, such tests will be counted as failed.
8933 By default, the test suite driver will run all tests, but there are
8934 several ways to limit the set of tests that are run:
8938 You can set the @code{TESTS} variable, similarly to how you can with
8939 the simple test driver from the previous section. For example, you can
8940 use a command like this to run only a subset of the tests:
8943 env TESTS="foo.test bar.test" make -e check
8946 Note however that the command above will unconditionally overwrite the
8947 @file{test-suite.log} file, thus clobbering the recorded results
8948 of any previous testsuite run. This might be undesirable for packages
8949 whose testsuite takes long time to execute. Luckily, this problem can
8950 easily be avoided by overriding also @code{TEST_SUITE_LOG} at runtime;
8953 @c Keep in sync with parallel-tests-log-override-2.test.
8955 env TEST_SUITE_LOG=partial.log TESTS="..." make -e check
8958 will write the result of the partial testsuite runs to the
8959 @file{partial.log}, without touching @file{test-suite.log}.
8962 You can set the @code{TEST_LOGS} variable. By default, this variable is
8963 computed at @command{make} run time from the value of @code{TESTS} as
8964 described above. For example, you can use the following:
8967 set x subset*.log; shift
8968 env TEST_LOGS="foo.log $*" make -e check
8971 The comments made above about @code{TEST_SUITE_LOG} overriding applies
8975 @vindex RECHECK_LOGS
8976 @cindex lazy test execution
8977 By default, the test driver removes all old per-test log files before it
8978 starts running tests to regenerate them. The variable
8979 @code{RECHECK_LOGS} contains the set of log files which are removed.
8980 @code{RECHECK_LOGS} defaults to @code{TEST_LOGS}, which means all tests
8981 need to be rechecked. By overriding this variable, you can choose which
8982 tests need to be reconsidered. For example, you can lazily rerun only
8983 those tests which are outdated, i.e., older than their prerequisite test
8984 files, by setting this variable to the empty value:
8987 env RECHECK_LOGS= make -e check
8992 @trindex recheck-html
8993 You can ensure that all tests are rerun which have failed or passed
8994 unexpectedly, by running @code{make recheck} in the test directory.
8995 This convenience target will set @code{RECHECK_LOGS} appropriately
8996 before invoking the main test driver. The @code{recheck-html} target
8997 does the same as @code{recheck} but again converts the resulting log
8998 file in HTML format, like the @code{check-html} target.
9001 In order to guarantee an ordering between tests even with @code{make
9002 -j@var{N}}, dependencies between the corresponding log files may be
9003 specified through usual @command{make} dependencies. For example, the
9004 following snippet lets the test named @file{foo-execute.test} depend
9005 upon completion of the test @file{foo-compile.test}:
9008 TESTS = foo-compile.test foo-execute.test
9009 foo-execute.log: foo-compile.log
9013 Please note that this ordering ignores the @emph{results} of required
9014 tests, thus the test @file{foo-execute.test} is run even if the test
9015 @file{foo-compile.test} failed or was skipped beforehand. Further,
9016 please note that specifying such dependencies currently works only for
9017 tests that end in one of the suffixes listed in @code{TEST_EXTENSIONS}.
9019 Tests without such specified dependencies may be run concurrently with
9020 parallel @command{make -j@var{N}}, so be sure they are prepared for
9021 concurrent execution.
9024 The combination of lazy test execution and correct dependencies between
9025 tests and their sources may be exploited for efficient unit testing
9026 during development. To further speed up the edit-compile-test cycle, it
9027 may even be useful to specify compiled programs in @code{EXTRA_PROGRAMS}
9028 instead of with @code{check_PROGRAMS}, as the former allows intertwined
9029 compilation and test execution (but note that @code{EXTRA_PROGRAMS} are
9030 not cleaned automatically, @pxref{Uniform}).
9032 The variables @code{TESTS} and @code{XFAIL_TESTS} may contain
9033 conditional parts as well as configure substitutions. In the latter
9034 case, however, certain restrictions apply: substituted test names
9035 must end with a nonempty test suffix like @file{.test}, so that one of
9036 the inference rules generated by @command{automake} can apply. For
9037 literal test names, @command{automake} can generate per-target rules
9038 to avoid this limitation.
9040 Please note that it is currently not possible to use @code{$(srcdir)/}
9041 or @code{$(top_srcdir)/} in the @code{TESTS} variable. This technical
9042 limitation is necessary to avoid generating test logs in the source tree
9043 and has the unfortunate consequence that it is not possible to specify
9044 distributed tests that are themselves generated by means of explicit
9045 rules, in a way that is portable to all @command{make} implementations
9046 (@pxref{Make Target Lookup,,, autoconf, The Autoconf Manual}, the
9047 semantics of FreeBSD and OpenBSD @command{make} conflict with this).
9048 In case of doubt you may want to require to use GNU @command{make},
9049 or work around the issue with inference rules to generate the tests.
9053 @section DejaGnu Tests
9055 If @uref{ftp://ftp.gnu.org/gnu/dejagnu/, @command{dejagnu}} appears in
9056 @code{AUTOMAKE_OPTIONS}, then a @command{dejagnu}-based test suite is
9057 assumed. The variable @code{DEJATOOL} is a list of names that are
9058 passed, one at a time, as the @option{--tool} argument to
9059 @command{runtest} invocations; it defaults to the name of the package.
9061 The variable @code{RUNTESTDEFAULTFLAGS} holds the @option{--tool} and
9062 @option{--srcdir} flags that are passed to dejagnu by default; this can be
9063 overridden if necessary.
9064 @vindex RUNTESTDEFAULTFLAGS
9066 The variables @code{EXPECT} and @code{RUNTEST} can
9067 also be overridden to provide project-specific values. For instance,
9068 you will need to do this if you are testing a compiler toolchain,
9069 because the default values do not take into account host and target
9076 The contents of the variable @code{RUNTESTFLAGS} are passed to the
9077 @code{runtest} invocation. This is considered a ``user variable''
9078 (@pxref{User Variables}). If you need to set @command{runtest} flags in
9079 @file{Makefile.am}, you can use @code{AM_RUNTESTFLAGS} instead.
9080 @vindex RUNTESTFLAGS
9081 @vindex AM_RUNTESTFLAGS
9083 @cindex @file{site.exp}
9084 Automake will generate rules to create a local @file{site.exp} file,
9085 defining various variables detected by @command{configure}. This file
9086 is automatically read by DejaGnu. It is OK for the user of a package
9087 to edit this file in order to tune the test suite. However this is
9088 not the place where the test suite author should define new variables:
9089 this should be done elsewhere in the real test suite code.
9090 Especially, @file{site.exp} should not be distributed.
9092 Still, if the package author has legitimate reasons to extend
9093 @file{site.exp} at @command{make} time, he can do so by defining
9094 the variable @code{EXTRA_DEJAGNU_SITE_CONFIG}; the files listed
9095 there will be considered @file{site.exp} prerequisites, and their
9096 content will be appended to it (in the same order in which they
9097 appear in @code{EXTRA_DEJAGNU_SITE_CONFIG}). Note that files are
9098 @emph{not} distributed by default.
9100 For more information regarding DejaGnu test suites, see @ref{Top, , ,
9101 dejagnu, The DejaGnu Manual}.
9103 In either case, the testing is done via @samp{make check}.
9106 @section Install Tests
9108 The @code{installcheck} target is available to the user as a way to
9109 run any tests after the package has been installed. You can add tests
9110 to this by writing an @code{installcheck-local} rule.
9114 @chapter Rebuilding Makefiles
9115 @cindex rebuild rules
9117 Automake generates rules to automatically rebuild @file{Makefile}s,
9118 @file{configure}, and other derived files like @file{Makefile.in}.
9120 @acindex AM_MAINTAINER_MODE
9121 If you are using @code{AM_MAINTAINER_MODE} in @file{configure.ac}, then
9122 these automatic rebuilding rules are only enabled in maintainer mode.
9124 @vindex ACLOCAL_AMFLAGS
9125 Sometimes you need to run @command{aclocal} with an argument like
9126 @option{-I} to tell it where to find @file{.m4} files. Since
9127 sometimes @command{make} will automatically run @command{aclocal}, you
9128 need a way to specify these arguments. You can do this by defining
9129 @code{ACLOCAL_AMFLAGS}; this holds arguments that are passed verbatim
9130 to @command{aclocal}. This variable is only useful in the top-level
9133 @vindex CONFIG_STATUS_DEPENDENCIES
9134 @vindex CONFIGURE_DEPENDENCIES
9135 @cindex @file{version.sh}, example
9136 @cindex @file{version.m4}, example
9138 Sometimes it is convenient to supplement the rebuild rules for
9139 @file{configure} or @file{config.status} with additional dependencies.
9140 The variables @code{CONFIGURE_DEPENDENCIES} and
9141 @code{CONFIG_STATUS_DEPENDENCIES} can be used to list these extra
9142 dependencies. These variables should be defined in all
9143 @file{Makefile}s of the tree (because these two rebuild rules are
9144 output in all them), so it is safer and easier to @code{AC_SUBST} them
9145 from @file{configure.ac}. For instance, the following statement will
9146 cause @file{configure} to be rerun each time @file{version.sh} is
9150 AC_SUBST([CONFIG_STATUS_DEPENDENCIES], ['$(top_srcdir)/version.sh'])
9154 Note the @samp{$(top_srcdir)/} in the file name. Since this variable
9155 is to be used in all @file{Makefile}s, its value must be sensible at
9156 any level in the build hierarchy.
9158 Beware not to mistake @code{CONFIGURE_DEPENDENCIES} for
9159 @code{CONFIG_STATUS_DEPENDENCIES}.
9161 @code{CONFIGURE_DEPENDENCIES} adds dependencies to the
9162 @file{configure} rule, whose effect is to run @command{autoconf}. This
9163 variable should be seldom used, because @command{automake} already tracks
9164 @code{m4_include}d files. However it can be useful when playing
9165 tricky games with @code{m4_esyscmd} or similar non-recommendable
9166 macros with side effects.
9168 @code{CONFIG_STATUS_DEPENDENCIES} adds dependencies to the
9169 @file{config.status} rule, whose effect is to run @file{configure}.
9170 This variable should therefore carry any non-standard source that may
9171 be read as a side effect of running @command{configure}, like @file{version.sh}
9172 in the example above.
9174 Speaking of @file{version.sh} scripts, we recommend against them
9175 today. They are mainly used when the version of a package is updated
9176 automatically by a script (e.g., in daily builds). Here is what some
9177 old-style @file{configure.ac}s may look like:
9181 . $srcdir/version.sh
9182 AM_INIT_AUTOMAKE([name], $VERSION_NUMBER)
9187 Here, @file{version.sh} is a shell fragment that sets
9188 @code{VERSION_NUMBER}. The problem with this example is that
9189 @command{automake} cannot track dependencies (listing @file{version.sh}
9190 in @command{CONFIG_STATUS_DEPENDENCIES}, and distributing this file is up
9191 to the user), and that it uses the obsolete form of @code{AC_INIT} and
9192 @code{AM_INIT_AUTOMAKE}. Upgrading to the new syntax is not
9193 straightforward, because shell variables are not allowed in
9194 @code{AC_INIT}'s arguments. We recommend that @file{version.sh} be
9195 replaced by an M4 file that is included by @file{configure.ac}:
9198 m4_include([version.m4])
9199 AC_INIT([name], VERSION_NUMBER)
9205 Here @file{version.m4} could contain something like
9206 @samp{m4_define([VERSION_NUMBER], [1.2])}. The advantage of this
9207 second form is that @command{automake} will take care of the
9208 dependencies when defining the rebuild rule, and will also distribute
9209 the file automatically. An inconvenience is that @command{autoconf}
9210 will now be rerun each time the version number is bumped, when only
9211 @file{configure} had to be rerun in the previous setup.
9215 @chapter Changing Automake's Behavior
9217 Various features of Automake can be controlled by options. Except where
9218 noted otherwise, options can be specified in one of several ways: Most
9219 options can be applied on a per-@file{Makefile} basis when listed in a
9220 special @file{Makefile} variable named @code{AUTOMAKE_OPTIONS}. Some
9221 of these options only make sense when specified in the toplevel
9222 @file{Makefile.am} file. Options are applied globally to all processed
9223 @file{Makefile} files when listed in the first argument of
9224 @code{AM_INIT_AUTOMAKE} in @file{configure.ac}, and some options which
9225 require changes to the @command{configure} script can only be specified
9226 there. These are annotated below.
9228 Currently understood options are:
9229 @vindex AUTOMAKE_OPTIONS
9232 @item @option{gnits}
9234 @itemx @option{foreign}
9235 @itemx @option{cygnus}
9236 @cindex Option, @option{gnits}
9237 @cindex Option, @option{gnu}
9238 @cindex Option, @option{foreign}
9239 @cindex Option, @option{cygnus}
9245 Set the strictness as appropriate. The @option{gnits} option also
9246 implies options @option{readme-alpha} and @option{check-news}.
9248 @item @option{ansi2knr}
9249 @itemx @option{@var{path}/ansi2knr}
9250 @cindex Option, @option{ansi2knr}
9252 Turn on the deprecated de-ANSI-fication feature (@pxref{ANSI}). Note
9253 that that feature and this option @emph{will be removed} in the next
9254 major Automake release.
9257 path, the generated @file{Makefile.in} will look in the specified
9258 directory to find the @file{ansi2knr} program. The path should be a
9259 relative path to another directory in the same distribution (Automake
9260 does not check this).
9262 @item @option{check-news}
9263 @cindex Option, @option{check-news}
9265 Cause @samp{make dist} to fail unless the current version number appears
9266 in the first few lines of the @file{NEWS} file.
9268 @item @option{color-tests}
9269 @cindex Option, @option{color-tests}
9270 @opindex color-tests
9271 Cause output of the simple test suite (@pxref{Simple Tests}) to be
9272 colorized on capable terminals.
9274 @item @option{dejagnu}
9275 @cindex Option, @option{dejagnu}
9277 Cause @command{dejagnu}-specific rules to be generated. @xref{DejaGnu Tests}.
9279 @item @option{dist-bzip2}
9280 @cindex Option, @option{dist-bzip2}
9282 Hook @code{dist-bzip2} to @code{dist}.
9285 @item @option{dist-lzma}
9286 @cindex Option, @option{dist-lzma}
9288 Hook @code{dist-lzma} to @code{dist}. Obsoleted by @code{dist-xz}.
9291 @item @option{dist-shar}
9292 @cindex Option, @option{dist-shar}
9294 Hook @code{dist-shar} to @code{dist}.
9297 @item @option{dist-zip}
9298 @cindex Option, @option{dist-zip}
9300 Hook @code{dist-zip} to @code{dist}.
9303 @item @option{dist-tarZ}
9304 @cindex Option, @option{dist-tarZ}
9306 Hook @code{dist-tarZ} to @code{dist}.
9309 @item @option{filename-length-max=99}
9310 @cindex Option, @option{filename-length-max=99}
9311 @opindex filename-length-max=99
9312 Abort if file names longer than 99 characters are found during
9313 @samp{make dist}. Such long file names are generally considered not to
9314 be portable in tarballs. See the @option{tar-v7} and @option{tar-ustar}
9315 options below. This option should be used in the top-level
9316 @file{Makefile.am} or as an argument of @code{AM_INIT_AUTOMAKE} in
9317 @file{configure.ac}, it will be ignored otherwise. It will also be
9318 ignored in sub-packages of nested packages (@pxref{Subpackages}).
9320 @item @option{no-define}
9321 @cindex Option, @option{no-define}
9323 This option is meaningful only when passed as an argument to
9324 @code{AM_INIT_AUTOMAKE}. It will prevent the @code{PACKAGE} and
9325 @code{VERSION} variables from being @code{AC_DEFINE}d.
9327 @item @option{no-dependencies}
9328 @cindex Option, @option{no-dependencies}
9329 @opindex no-dependencies
9330 This is similar to using @option{--ignore-deps} on the command line,
9331 but is useful for those situations where you don't have the necessary
9332 bits to make automatic dependency tracking work
9333 (@pxref{Dependencies}). In this case the effect is to effectively
9334 disable automatic dependency tracking.
9336 @item @option{no-dist}
9337 @cindex Option, @option{no-dist}
9339 Don't emit any code related to @code{dist} target. This is useful
9340 when a package has its own method for making distributions.
9342 @item @option{no-dist-gzip}
9343 @cindex Option, @option{no-dist-gzip}
9344 @opindex no-dist-gzip
9345 Do not hook @code{dist-gzip} to @code{dist}.
9346 @trindex no-dist-gzip
9348 @item @option{no-exeext}
9349 @cindex Option, @option{no-exeext}
9351 If your @file{Makefile.am} defines a rule for target @code{foo}, it
9352 will override a rule for a target named @samp{foo$(EXEEXT)}. This is
9353 necessary when @code{EXEEXT} is found to be empty. However, by
9354 default @command{automake} will generate an error for this use. The
9355 @option{no-exeext} option will disable this error. This is intended for
9356 use only where it is known in advance that the package will not be
9357 ported to Windows, or any other operating system using extensions on
9360 @item @option{no-installinfo}
9361 @cindex Option, @option{no-installinfo}
9362 @opindex no-installinfo
9363 The generated @file{Makefile.in} will not cause info pages to be built
9364 or installed by default. However, @code{info} and @code{install-info}
9365 targets will still be available. This option is disallowed at
9366 @option{gnu} strictness and above.
9368 @trindex install-info
9370 @item @option{no-installman}
9371 @cindex Option, @option{no-installman}
9372 @opindex no-installman
9373 The generated @file{Makefile.in} will not cause man pages to be
9374 installed by default. However, an @code{install-man} target will still
9375 be available for optional installation. This option is disallowed at
9376 @option{gnu} strictness and above.
9377 @trindex install-man
9379 @item @option{nostdinc}
9380 @cindex Option, @option{nostdinc}
9382 This option can be used to disable the standard @option{-I} options that
9383 are ordinarily automatically provided by Automake.
9385 @item @option{no-texinfo.tex}
9386 @cindex Option, @option{no-texinfo.tex}
9387 @opindex no-texinfo.tex
9388 Don't require @file{texinfo.tex}, even if there are texinfo files in
9391 @item @option{parallel-tests}
9392 @cindex Option, @option{parallel-tests}
9393 @opindex parallel-tests
9394 Enable test suite driver for @code{TESTS} that can run tests in parallel
9395 (@pxref{Simple Tests using parallel-tests}, for more information).
9397 @item @option{readme-alpha}
9398 @cindex Option, @option{readme-alpha}
9399 @opindex readme-alpha
9400 If this release is an alpha release, and the file @file{README-alpha}
9401 exists, then it will be added to the distribution. If this option is
9402 given, version numbers are expected to follow one of two forms. The
9403 first form is @samp{@var{major}.@var{minor}.@var{alpha}}, where each
9404 element is a number; the final period and number should be left off for
9405 non-alpha releases. The second form is
9406 @samp{@var{major}.@var{minor}@var{alpha}}, where @var{alpha} is a
9407 letter; it should be omitted for non-alpha releases.
9409 @item @option{silent-rules}
9410 @cindex Option, @option{silent-rules}
9411 @opindex silent-rules
9412 Enable less verbose build rules. This can be used to let build rules
9413 output status lines of the form:
9415 GEN @var{output-file}
9416 CC @var{object-file}
9419 instead of printing the command that will be executed to update
9420 @var{output-file} or to compile @var{object-file}. It can also
9421 silence @command{libtool} output.
9423 For more information about how to use, enable, or disable silent
9424 rules, @pxref{Automake silent-rules Option}.
9426 @item @option{std-options}
9427 @cindex Options, @option{std-options}
9428 @cindex @samp{make installcheck}, testing @option{--help} and @option{--version}
9429 @cindex @option{--help} check
9430 @cindex @option{--version} check
9431 @opindex std-options
9433 Make the @code{installcheck} rule check that installed scripts and
9434 programs support the @option{--help} and @option{--version} options.
9435 This also provides a basic check that the program's
9436 run-time dependencies are satisfied after installation.
9438 @vindex AM_INSTALLCHECK_STD_OPTIONS_EXEMPT
9439 In a few situations, programs (or scripts) have to be exempted from this
9440 test. For instance, @command{false} (from GNU coreutils) is never
9441 successful, even for @option{--help} or @option{--version}. You can list
9442 such programs in the variable @code{AM_INSTALLCHECK_STD_OPTIONS_EXEMPT}.
9443 Programs (not scripts) listed in this variable should be suffixed by
9444 @samp{$(EXEEXT)} for the sake of Win32 or OS/2. For instance, suppose we
9445 build @file{false} as a program but @file{true.sh} as a script, and that
9446 neither of them support @option{--help} or @option{--version}:
9449 AUTOMAKE_OPTIONS = std-options
9450 bin_PROGRAMS = false ...
9451 bin_SCRIPTS = true.sh ...
9452 AM_INSTALLCHECK_STD_OPTIONS_EXEMPT = false$(EXEEXT) true.sh
9455 @item @option{subdir-objects}
9456 @cindex Options, @option{subdir-objects}
9457 @opindex subdir-objects
9458 If this option is specified, then objects are placed into the
9459 subdirectory of the build directory corresponding to the subdirectory of
9460 the source file. For instance, if the source file is
9461 @file{subdir/file.cxx}, then the output file would be
9462 @file{subdir/file.o}.
9464 In order to use this option with C sources, you should add
9465 @code{AM_PROG_CC_C_O} to @file{configure.ac}.
9467 @anchor{tar-formats}
9468 @item @option{tar-v7}
9469 @itemx @option{tar-ustar}
9470 @itemx @option{tar-pax}
9471 @cindex Option, @option{tar-v7}
9472 @cindex Option, @option{tar-ustar}
9473 @cindex Option, @option{tar-pax}
9474 @cindex @command{tar} formats
9475 @cindex v7 @command{tar} format
9476 @cindex ustar format
9482 These three mutually exclusive options select the tar format to use
9483 when generating tarballs with @samp{make dist}. (The tar file created
9484 is then compressed according to the set of @option{no-dist-gzip},
9485 @option{dist-bzip2}, @option{dist-xz} and @option{dist-tarZ} options in use.)
9487 These options must be passed as arguments to @code{AM_INIT_AUTOMAKE}
9488 (@pxref{Macros}) because they can require additional configure checks.
9489 Automake will complain if it sees such options in an
9490 @code{AUTOMAKE_OPTIONS} variable.
9492 @option{tar-v7} selects the old V7 tar format. This is the historical
9493 default. This antiquated format is understood by all tar
9494 implementations and supports file names with up to 99 characters. When
9495 given longer file names some tar implementations will diagnose the
9496 problem while other will generate broken tarballs or use non-portable
9497 extensions. Furthermore, the V7 format cannot store empty
9498 directories. When using this format, consider using the
9499 @option{filename-length-max=99} option to catch file names too long.
9501 @option{tar-ustar} selects the ustar format defined by POSIX
9502 1003.1-1988. This format is believed to be old enough to be portable.
9503 It fully supports empty directories. It can store file names with up
9504 to 256 characters, provided that the file name can be split at
9505 directory separator in two parts, first of them being at most 155
9506 bytes long. So, in most cases the maximum file name length will be
9507 shorter than 256 characters. However you may run against broken tar
9508 implementations that incorrectly handle file names longer than 99
9509 characters (please report them to @email{@value{PACKAGE_BUGREPORT}} so we
9510 can document this accurately).
9512 @option{tar-pax} selects the new pax interchange format defined by POSIX
9513 1003.1-2001. It does not limit the length of file names. However,
9514 this format is very young and should probably be restricted to
9515 packages that target only very modern platforms. There are moves to
9516 change the pax format in an upward-compatible way, so this option may
9517 refer to a more recent version in the future.
9519 @xref{Formats, , Controlling the Archive Format, tar, GNU Tar}, for
9520 further discussion about tar formats.
9522 @command{configure} knows several ways to construct these formats. It
9523 will not abort if it cannot find a tool up to the task (so that the
9524 package can still be built), but @samp{make dist} will fail.
9527 @cindex Option, @var{version}
9528 A version number (e.g., @samp{0.30}) can be specified. If Automake is not
9529 newer than the version specified, creation of the @file{Makefile.in}
9532 @item @option{-W@var{category}} or @option{--warnings=@var{category}}
9533 @cindex Option, warnings
9534 @cindex Option, @option{-W@var{category}}
9535 @cindex Option, @option{--warnings=@var{category}}
9536 These options behave exactly like their command-line counterpart
9537 (@pxref{Invoking Automake}). This allows you to enable or disable some
9538 warning categories on a per-file basis. You can also setup some warnings
9539 for your entire project; for instance, try @samp{AM_INIT_AUTOMAKE([-Wall])}
9540 in your @file{configure.ac}.
9544 Unrecognized options are diagnosed by @command{automake}.
9546 If you want an option to apply to all the files in the tree, you can use
9547 the @code{AM_INIT_AUTOMAKE} macro in @file{configure.ac}.
9552 @chapter Miscellaneous Rules
9554 There are a few rules and variables that didn't fit anywhere else.
9557 * Tags:: Interfacing to etags and mkid
9558 * Suffixes:: Handling new file extensions
9559 * Multilibs:: Support for multilibs.
9564 @section Interfacing to @command{etags}
9566 @cindex @file{TAGS} support
9568 Automake will generate rules to generate @file{TAGS} files for use with
9569 GNU Emacs under some circumstances.
9572 If any C, C++ or Fortran 77 source code or headers are present, then
9573 @code{tags} and @code{TAGS} rules will be generated for the directory.
9574 All files listed using the @code{_SOURCES}, @code{_HEADERS}, and
9575 @code{_LISP} primaries will be used to generate tags. Note that
9576 generated source files that are not distributed must be declared in
9577 variables like @code{nodist_noinst_HEADERS} or
9578 @code{nodist_@var{prog}_SOURCES} or they will be ignored.
9580 A @code{tags} rule will be output at the topmost directory of a
9581 multi-directory package. When run from this topmost directory,
9582 @samp{make tags} will generate a @file{TAGS} file that includes by
9583 reference all @file{TAGS} files from subdirectories.
9585 The @code{tags} rule will also be generated if the variable
9586 @code{ETAGS_ARGS} is defined. This variable is intended for use in
9587 directories that contain taggable source that @command{etags} does
9588 not understand. The user can use the @code{ETAGSFLAGS} to pass
9589 additional flags to @command{etags}; @code{AM_ETAGSFLAGS} is also
9590 available for use in @file{Makefile.am}.
9593 @vindex AM_ETAGSFLAGS
9595 Here is how Automake generates tags for its source, and for nodes in its
9599 ETAGS_ARGS = automake.in --lang=none \
9600 --regex='/^@@node[ \t]+\([^,]+\)/\1/' automake.texi
9603 If you add file names to @code{ETAGS_ARGS}, you will probably also
9604 want to define @code{TAGS_DEPENDENCIES}. The contents of this variable
9605 are added directly to the dependencies for the @code{tags} rule.
9606 @vindex TAGS_DEPENDENCIES
9608 Automake also generates a @code{ctags} rule that can be used to
9609 build @command{vi}-style @file{tags} files. The variable @code{CTAGS}
9610 is the name of the program to invoke (by default @command{ctags});
9611 @code{CTAGSFLAGS} can be used by the user to pass additional flags,
9612 and @code{AM_CTAGSFLAGS} can be used by the @file{Makefile.am}.
9614 Automake will also generate an @code{ID} rule that will run
9615 @command{mkid} on the source. This is only supported on a
9616 directory-by-directory basis.
9619 Finally, Automake also emits rules to support the
9620 @uref{http://www.gnu.org/software/global/, GNU Global Tags program}.
9621 The @code{GTAGS} rule runs Global Tags and puts the
9622 result in the top build directory. The variable @code{GTAGS_ARGS}
9623 holds arguments that are passed to @command{gtags}.
9628 @section Handling new file extensions
9630 @cindex Adding new @code{SUFFIXES}
9631 @cindex @code{SUFFIXES}, adding
9634 It is sometimes useful to introduce a new implicit rule to handle a file
9635 type that Automake does not know about.
9637 For instance, suppose you had a compiler that could compile @file{.foo}
9638 files to @file{.o} files. You would simply define a suffix rule for
9646 Then you could directly use a @file{.foo} file in a @code{_SOURCES}
9647 variable and expect the correct results:
9651 doit_SOURCES = doit.foo
9654 This was the simpler and more common case. In other cases, you will
9655 have to help Automake to figure out which extensions you are defining your
9656 suffix rule for. This usually happens when your extension does not
9657 start with a dot. Then, all you have to do is to put a list of new
9658 suffixes in the @code{SUFFIXES} variable @strong{before} you define your
9661 For instance, the following definition prevents Automake from misinterpreting
9662 the @samp{.idlC.cpp:} rule as an attempt to transform @file{.idlC} files into
9665 @c Keep in sync with suffix7.test.
9667 SUFFIXES = .idl C.cpp
9672 As you may have noted, the @code{SUFFIXES} variable behaves like the
9673 @code{.SUFFIXES} special target of @command{make}. You should not touch
9674 @code{.SUFFIXES} yourself, but use @code{SUFFIXES} instead and let
9675 Automake generate the suffix list for @code{.SUFFIXES}. Any given
9676 @code{SUFFIXES} go at the start of the generated suffixes list, followed
9677 by Automake generated suffixes not already in the list.
9680 @section Support for Multilibs
9682 Automake has support for an obscure feature called multilibs. A
9683 @dfn{multilib} is a library that is built for multiple different ABIs
9684 at a single time; each time the library is built with a different target
9685 flag combination. This is only useful when the library is intended to
9686 be cross-compiled, and it is almost exclusively used for compiler
9689 The multilib support is still experimental. Only use it if you are
9690 familiar with multilibs and can debug problems you might encounter.
9697 @cindex Including @file{Makefile} fragment
9698 @cindex @file{Makefile} fragment, including
9700 Automake supports an @code{include} directive that can be used to
9701 include other @file{Makefile} fragments when @command{automake} is run.
9702 Note that these fragments are read and interpreted by @command{automake},
9703 not by @command{make}. As with conditionals, @command{make} has no idea that
9704 @code{include} is in use.
9706 There are two forms of @code{include}:
9709 @item include $(srcdir)/file
9710 Include a fragment that is found relative to the current source
9713 @item include $(top_srcdir)/file
9714 Include a fragment that is found relative to the top source directory.
9717 Note that if a fragment is included inside a conditional, then the
9718 condition applies to the entire contents of that fragment.
9720 Makefile fragments included this way are always distributed because
9721 they are needed to rebuild @file{Makefile.in}.
9724 @chapter Conditionals
9726 @cindex Conditionals
9728 Automake supports a simple type of conditionals.
9730 These conditionals are not the same as conditionals in
9731 GNU Make. Automake conditionals are checked at configure time by the
9732 @file{configure} script, and affect the translation from
9733 @file{Makefile.in} to @file{Makefile}. They are based on options passed
9734 to @file{configure} and on results that @file{configure} has discovered
9735 about the host system. GNU Make conditionals are checked at @command{make}
9736 time, and are based on variables passed to the make program or defined
9737 in the @file{Makefile}.
9739 Automake conditionals will work with any make program.
9742 * Usage of Conditionals:: Declaring conditional content
9743 * Limits of Conditionals:: Enclosing complete statements
9746 @node Usage of Conditionals
9747 @section Usage of Conditionals
9749 @acindex AM_CONDITIONAL
9750 Before using a conditional, you must define it by using
9751 @code{AM_CONDITIONAL} in the @file{configure.ac} file (@pxref{Macros}).
9753 @defmac AM_CONDITIONAL (@var{conditional}, @var{condition})
9754 The conditional name, @var{conditional}, should be a simple string
9755 starting with a letter and containing only letters, digits, and
9756 underscores. It must be different from @samp{TRUE} and @samp{FALSE}
9757 that are reserved by Automake.
9759 The shell @var{condition} (suitable for use in a shell @code{if}
9760 statement) is evaluated when @command{configure} is run. Note that you
9761 must arrange for @emph{every} @code{AM_CONDITIONAL} to be invoked every
9762 time @command{configure} is run. If @code{AM_CONDITIONAL} is run
9763 conditionally (e.g., in a shell @code{if} statement), then the result
9764 will confuse @command{automake}.
9767 @cindex @option{--enable-debug}, example
9768 @cindex Example conditional @option{--enable-debug}
9769 @cindex Conditional example, @option{--enable-debug}
9771 Conditionals typically depend upon options that the user provides to
9772 the @command{configure} script. Here is an example of how to write a
9773 conditional that is true if the user uses the @option{--enable-debug}
9777 AC_ARG_ENABLE([debug],
9778 [ --enable-debug Turn on debugging],
9779 [case "$@{enableval@}" in
9782 *) AC_MSG_ERROR([bad value $@{enableval@} for --enable-debug]) ;;
9783 esac],[debug=false])
9784 AM_CONDITIONAL([DEBUG], [test x$debug = xtrue])
9787 Here is an example of how to use that conditional in @file{Makefile.am}:
9799 noinst_PROGRAMS = $(DBG)
9802 This trivial example could also be handled using @code{EXTRA_PROGRAMS}
9803 (@pxref{Conditional Programs}).
9805 You may only test a single variable in an @code{if} statement, possibly
9806 negated using @samp{!}. The @code{else} statement may be omitted.
9807 Conditionals may be nested to any depth. You may specify an argument to
9808 @code{else} in which case it must be the negation of the condition used
9809 for the current @code{if}. Similarly you may specify the condition
9810 that is closed on the @code{endif} line:
9821 Unbalanced conditions are errors. The @code{if}, @code{else}, and
9822 @code{endif} statements should not be indented, i.e., start on column
9825 The @code{else} branch of the above two examples could be omitted,
9826 since assigning the empty string to an otherwise undefined variable
9827 makes no difference.
9830 In order to allow access to the condition registered by
9831 @code{AM_CONDITIONAL} inside @file{configure.ac}, and to allow
9832 conditional @code{AC_CONFIG_FILES}, @code{AM_COND_IF} may be used:
9834 @defmac AM_COND_IF (@var{conditional}, @ovar{if-true}, @ovar{if-false})
9835 If @var{conditional} is fulfilled, execute @var{if-true}, otherwise
9836 execute @var{if-false}. If either branch contains @code{AC_CONFIG_FILES},
9837 it will cause @command{automake} to output the rules for the respective
9838 files only for the given condition.
9841 @code{AM_COND_IF} macros may be nested when m4 quotation is used
9842 properly (@pxref{M4 Quotation, ,, autoconf, The Autoconf Manual}).
9844 @cindex Example conditional @code{AC_CONFIG_FILES}
9845 @cindex @code{AC_CONFIG_FILES}, conditional
9847 Here is an example of how to define a conditional config file:
9850 AM_CONDITIONAL([SHELL_WRAPPER], [test "x$with_wrapper" = xtrue])
9851 AM_COND_IF([SHELL_WRAPPER],
9852 [AC_CONFIG_FILES([wrapper:wrapper.in])])
9855 @node Limits of Conditionals
9856 @section Limits of Conditionals
9858 Conditionals should enclose complete statements like variables or
9859 rules definitions. Automake cannot deal with conditionals used inside
9860 a variable definition, for instance, and is not even able to diagnose
9861 this situation. The following example would not work:
9864 # This syntax is not understood by Automake
9873 However the intended definition of @code{AM_CPPFLAGS} can be achieved
9878 DEBUGFLAGS = -DDEBUG
9880 AM_CPPFLAGS = -DFEATURE_A $(DEBUGFLAGS) -DFEATURE_B
9887 AM_CPPFLAGS = -DFEATURE_A
9889 AM_CPPFLAGS += -DDEBUG
9891 AM_CPPFLAGS += -DFEATURE_B
9894 More details and examples of conditionals are described alongside
9895 various Automake features in this manual (@pxref{Conditional
9896 Subdirectories}, @pxref{Conditional Sources}, @pxref{Conditional
9897 Programs}, @pxref{Conditional Libtool Libraries}, @pxref{Conditional
9900 @node Silencing Make
9901 @chapter Silencing @command{make}
9903 @cindex Silent @command{make}
9904 @cindex Silencing @command{make}
9905 @cindex Silent rules
9906 @cindex Silent @command{make} rules
9909 * Make verbosity:: Make is verbose by default
9910 * Tricks For Silencing Make:: Standard and generic ways to silence make
9911 * Automake silent-rules Option:: How Automake can help in silencing make
9914 @node Make verbosity
9915 @section Make is verbose by default
9917 Normally, when executing the set of rules associated with a target,
9918 @command{make} prints each rule before it is executed. This behaviour,
9919 while having been in place for a long time, and being even mandated by
9920 the POSIX standard, starkly violates the ``silence is golden'' UNIX
9921 principle@footnote{See also
9922 @uref{http://catb.org/~esr/writings/taoup/html/ch11s09.html}.}:
9925 When a program has nothing interesting or surprising to say, it should
9926 say nothing. Well-behaved Unix programs do their jobs unobtrusively,
9927 with a minimum of fuss and bother. Silence is golden.
9930 In fact, while such verbosity of @command{make} can theoretically be
9931 useful to track bugs and understand reasons of failures right away, it
9932 can also hide warning and error messages from @command{make}-invoked
9933 tools, drowning them in a flood of uninteresting and seldom useful
9934 messages, and thus allowing them to go easily undetected.
9936 This problem can be very annoying, especially for developers, who usually
9937 know quite well what's going on behind the scenes, and for whom the
9938 verbose output from @command{make} ends up being mostly noise that hampers
9939 the easy detection of potentially important warning messages.
9941 @node Tricks For Silencing Make
9942 @section Standard and generic ways to silence make
9944 Here we describe some common idioms/tricks to obtain a quieter make
9945 output, with their relative advantages and drawbacks. In the next
9946 section (@ref{Automake silent-rules Option}) we'll see how Automake
9947 can help in this respect.
9951 @item @command{make -s}
9953 This simply causes @command{make} not to print @emph{any} rule before
9956 The @option{-s} flag is mandated by POSIX, universally supported, and
9957 its purpose and function are easy to understand.
9959 But it also has its serious limitations too. First of all, it embodies
9960 an ``all or nothing'' strategy, i.e., either everything is silenced, or
9961 nothing is; this lack of granularity can sometimes be a fatal flaw.
9962 Moreover, when the @option{-s} flag is used, the @command{make} output
9963 might turn out to be too much terse; in case of errors, the user won't
9964 be able to easily see what rule or command have caused them, or even,
9965 in case of tools with poor error reporting, what the errors were!
9967 @item @command{make >/dev/null || make}
9969 Apparently, this perfectly obeys the ``silence is golden'' rule: warnings
9970 from stderr are passed through, output reporting is done only in case of
9971 error, and in that case it should provide a verbose-enough report to allow
9972 an easy determination of the error location and causes.
9974 However, calling @command{make} two times in a row might hide errors
9975 (especially intermittent ones), or subtly change the expected semantic
9976 of the @command{make} calls --- things these which can clearly make
9977 debugging and error assessment very difficult.
9979 @item @command{make --no-print-directory}
9981 This is GNU @command{make} specific. When called with the
9982 @option{--no-print-directory} option, GNU @command{make} will disable
9983 printing of the working directory by invoked sub-@command{make}s (the
9984 well-known ``@i{Entering/Leaving directory ...}'' messages). This helps
9985 to decrease the verbosity of the output, but experience has shown that
9986 it can also often render debugging considerably harder in projects using
9987 deeply-nested @command{make} recursion.
9989 As an aside, notice that the @option{--no-print-directory} option is
9990 automatically activated if the @option{-s} flag is used.
9992 @c TODO: Other tricks?
9993 @c TODO: Maybe speak about the @code{.SILENT} target?
9994 @c TODO: - Pros: More granularity on what to silence.
9995 @c TODO: - Cons: No easy way to temporarily override.
9999 @node Automake silent-rules Option
10000 @section How Automake can help in silencing make
10002 The tricks and idioms for silencing @command{make} described in the
10003 previous section can be useful from time to time, but we've seen that
10004 they all have their serious drawbacks and limitations. That's why
10005 automake provides support for a more advanced and flexible way of
10006 obtaining quieter output from @command{make}: the @option{silent-rules}
10009 @c TODO: Maybe describe in brief the precedent set by the build system
10010 @c of the Linux Kernel, from which Automake took inspiration ... Links?
10012 To give the gist of what @option{silent-rules} can do, here is a simple
10013 comparison between a typical @command{make} output (where silent rules
10014 are disabled) and one with silent rules enabled:
10017 % @kbd{cat Makefile.am}
10019 foo_SOURCES = main.c func.c
10021 int main (void) @{ return func (); @} /* func used undeclared */
10023 int func (void) @{ int i; return i; @} /* i used uninitialized */
10025 @i{The make output is by default very verbose. This causes warnings
10026 from the compiler to be somewhat hidden, and not immediate to spot.}
10027 % @kbd{make CFLAGS=-Wall}
10028 gcc -DPACKAGE_NAME=\"foo\" -DPACKAGE_TARNAME=\"foo\" ...
10029 -DPACKAGE_STRING=\"foo\ 1.0\" -DPACKAGE_BUGREPORT=\"\" ...
10030 -DPACKAGE=\"foo\" -DVERSION=\"1.0\" -I. -Wall -MT main.o
10031 -MD -MP -MF .deps/main.Tpo -c -o main.o main.c
10032 main.c: In function ‘main’:
10033 main.c:3:3: warning: implicit declaration of function ‘func’
10034 mv -f .deps/main.Tpo .deps/main.Po
10035 gcc -DPACKAGE_NAME=\"foo\" -DPACKAGE_TARNAME=\"foo\" ...
10036 -DPACKAGE_STRING=\"foo\ 1.0\" -DPACKAGE_BUGREPORT=\"\" ...
10037 -DPACKAGE=\"foo\" -DVERSION=\"1.0\" -I. -Wall -MT func.o
10038 -MD -MP -MF .deps/func.Tpo -c -o func.o func.c
10039 func.c: In function ‘func’:
10040 func.c:4:3: warning: ‘i’ used uninitialized in this function
10041 mv -f .deps/func.Tpo .deps/func.Po
10042 gcc -Wall -o foo main.o func.o
10044 @i{Clean up, so that we we can rebuild everything from scratch.}
10046 test -z "foo" || rm -f foo
10049 @i{Silent rules enabled: the output is minimal but informative. In
10050 particular, the warnings from the compiler stick out very clearly.}
10051 % @kbd{make V=0 CFLAGS=-Wall}
10053 main.c: In function ‘main’:
10054 main.c:3:3: warning: implicit declaration of function ‘func’
10056 func.c: In function ‘func’:
10057 func.c:4:3: warning: ‘i’ used uninitialized in this function
10061 @cindex silent-rules and libtool
10062 Also, in projects using @command{libtool}, the use of silent rules can
10063 automatically enable the @command{libtool}'s @option{--silent} option:
10066 % @kbd{cat Makefile.am}
10067 lib_LTLIBRARIES = libx.la
10069 % @kbd{make # Both make and libtool are verbose by default.}
10071 libtool: compile: gcc -DPACKAGE_NAME=\"foo\" ... -DLT_OBJDIR=\".libs/\"
10072 -I. -g -O2 -MT libx.lo -MD -MP -MF .deps/libx.Tpo -c libx.c -fPIC
10073 -DPIC -o .libs/libx.o
10074 mv -f .deps/libx.Tpo .deps/libx.Plo
10075 /bin/sh ./libtool --tag=CC --mode=link gcc -g -O2 -o libx.la -rpath
10076 /usr/local/lib libx.lo
10077 libtool: link: gcc -shared .libs/libx.o -Wl,-soname -Wl,libx.so.0
10078 -o .libs/libx.so.0.0.0
10079 libtool: link: cd .libs && rm -f libx.so && ln -s libx.so.0.0.0 libx.so
10087 Let's now see how the @option{silent-rules} mode interfaces with the
10088 package developer and the package user.
10090 To enable the use of @option{silent-rules} in his package, a developer
10091 needs to do either of the following:
10095 Add the @option{silent-rules} option as argument to @code{AM_INIT_AUTOMAKE}.
10097 Call the @code{AM_SILENT_RULES} macro from within the @file{configure.ac}
10101 It is not possible to instead specify @option{silent-rules} in a
10102 @file{Makefile.am} file.
10104 If the developer has done either of the above, then the user of the
10105 package may influence the verbosity at @command{configure} run time as
10106 well as at @command{make} run time:
10110 @opindex --enable-silent-rules
10111 @opindex --disable-silent-rules
10112 Passing @option{--enable-silent-rules} to @command{configure} will cause
10113 build rules to be less verbose; the option @option{--disable-silent-rules}
10114 will cause normal verbose output.
10117 At @command{make} run time, the default chosen at @command{configure}
10118 time may be overridden: @code{make V=1} will produce verbose output,
10119 @code{make V=0} less verbose output.
10122 @cindex default verbosity for silent-rules
10123 Note that silent rules are @emph{disabled} by default; the user must
10124 enable them explicitly at either @command{configure} run time or at
10125 @command{make} run time. We think that this is a good policy, since
10126 it provides the casual user with enough information to prepare a good
10127 bug report in case anything breaks.
10129 Still, notwithstanding the rationales above, a developer who wants to
10130 make silent rules enabled by default in his own package can do so by
10131 adding a @samp{yes} argument to the @code{AM_SILENT_RULES} call in
10132 @file{configure.ac}. We advise against this approach, though.
10134 @c Keep in sync with silent-configsite.test
10135 Users who prefer to have silent rules enabled by default can edit their
10136 @file{config.site} file to make the variable @code{enable_silent_rules}
10137 default to @samp{yes}. This should still allow disabling silent rules
10138 at @command{configure} time and at @command{make} time.
10140 @c FIXME: there's really a need to specify this explicitly?
10141 For portability to different @command{make} implementations, package authors
10142 are advised to not set the variable @code{V} inside the @file{Makefile.am}
10143 file, to allow the user to override the value for subdirectories as well.
10145 The current implementation of this feature relies on a non-POSIX, but in
10146 practice rather widely supported @file{Makefile} construct of nested
10147 variable expansion @samp{$(@var{var1}$(V))}. Do not use the
10148 @option{silent-rules} option if your package needs to build with
10149 @command{make} implementations that do not support it. The
10150 @option{silent-rules} option turns off warnings about recursive variable
10151 expansion, which are in turn enabled by @option{-Wportability}
10152 (@pxref{Invoking Automake}).
10154 @vindex @code{AM_V_GEN}
10155 @vindex @code{AM_V_at}
10156 @vindex @code{AM_DEFAULT_VERBOSITY}
10157 To extend the silent mode to your own rules, you have two choices:
10161 You can use the predefined variable @code{AM_V_GEN} as a prefix to
10162 commands that should output a status line in silent mode, and
10163 @code{AM_V_at} as a prefix to commands that should not output anything
10164 in silent mode. When output is to be verbose, both of these variables
10165 will expand to the empty string.
10167 You can add your own variables, so strings of your own choice are shown.
10168 The following snippet shows how you would define your own equivalent of
10172 pkg_verbose = $(pkg_verbose_$(V))
10173 pkg_verbose_ = $(pkg_verbose_$(AM_DEFAULT_VERBOSITY))
10174 pkg_verbose_0 = @@echo PKG-GEN $@@;
10177 $(pkg_verbose)cp $(srcdir)/foo.in $@@
10182 As a final note, observe that, even when silent rules are enabled,
10183 the @option{--no-print-directory} option is still required with GNU
10184 @command{make} if the ``@i{Entering/Leaving directory ...}'' messages
10185 are to be disabled.
10188 @chapter The effect of @option{--gnu} and @option{--gnits}
10190 @cindex @option{--gnu}, required files
10191 @cindex @option{--gnu}, complete description
10193 The @option{--gnu} option (or @option{gnu} in the
10194 @code{AUTOMAKE_OPTIONS} variable) causes @command{automake} to check
10199 The files @file{INSTALL}, @file{NEWS}, @file{README}, @file{AUTHORS},
10200 and @file{ChangeLog}, plus one of @file{COPYING.LIB}, @file{COPYING.LESSER}
10201 or @file{COPYING}, are required at the topmost directory of the package.
10203 If the @option{--add-missing} option is given, @command{automake} will
10204 add a generic version of the @file{INSTALL} file as well as the
10205 @file{COPYING} file containing the text of the current version of the
10206 GNU General Public License existing at the time of this Automake release
10207 (version 3 as this is written, @uref{http://www.gnu.org/@/copyleft/@/gpl.html}).
10208 However, an existing @file{COPYING} file will never be overwritten by
10209 @command{automake}.
10212 The options @option{no-installman} and @option{no-installinfo} are
10216 Note that this option will be extended in the future to do even more
10217 checking; it is advisable to be familiar with the precise requirements
10218 of the GNU standards. Also, @option{--gnu} can require certain
10219 non-standard GNU programs to exist for use by various maintainer-only
10220 rules; for instance, in the future @command{pathchk} might be required for
10223 @cindex @option{--gnits}, complete description
10225 The @option{--gnits} option does everything that @option{--gnu} does, and
10226 checks the following as well:
10230 @samp{make installcheck} will check to make sure that the @option{--help}
10231 and @option{--version} really print a usage message and a version string,
10232 respectively. This is the @option{std-options} option (@pxref{Options}).
10235 @samp{make dist} will check to make sure the @file{NEWS} file has been
10236 updated to the current version.
10239 @code{VERSION} is checked to make sure its format complies with Gnits
10241 @c FIXME xref when standards are finished
10244 @cindex @file{README-alpha}
10245 If @code{VERSION} indicates that this is an alpha release, and the file
10246 @file{README-alpha} appears in the topmost directory of a package, then
10247 it is included in the distribution. This is done in @option{--gnits}
10248 mode, and no other, because this mode is the only one where version
10249 number formats are constrained, and hence the only mode where Automake
10250 can automatically determine whether @file{README-alpha} should be
10254 The file @file{THANKS} is required.
10259 @chapter The effect of @option{--cygnus}
10261 @cindex @option{cygnus} strictness
10263 Some packages, notably GNU GCC and GNU gdb, have a build environment
10264 originally written at Cygnus Support (subsequently renamed Cygnus
10265 Solutions, and then later purchased by Red Hat). Packages with this
10266 ancestry are sometimes referred to as ``Cygnus'' trees.
10268 A Cygnus tree has slightly different rules for how a
10269 @file{Makefile.in} is to be constructed. Passing @option{--cygnus} to
10270 @command{automake} will cause any generated @file{Makefile.in} to
10271 comply with Cygnus rules.
10273 Here are the precise effects of @option{--cygnus}:
10277 Info files are always created in the build directory, and not in the
10281 @file{texinfo.tex} is not required if a Texinfo source file is
10282 specified. The assumption is that the file will be supplied, but in a
10283 place that Automake cannot find. This assumption is an artifact of how
10284 Cygnus packages are typically bundled.
10287 @samp{make dist} is not supported, and the rules for it are not
10288 generated. Cygnus-style trees use their own distribution mechanism.
10291 Certain tools will be searched for in the build tree as well as in the
10292 user's @env{PATH}. These tools are @command{runtest}, @command{expect},
10293 @command{makeinfo} and @command{texi2dvi}.
10296 @option{--foreign} is implied.
10299 The options @option{no-installinfo} and @option{no-dependencies} are
10303 The macro @code{AM_MAINTAINER_MODE} is required.
10306 The @code{check} target doesn't depend on @code{all}.
10309 GNU maintainers are advised to use @option{gnu} strictness in preference
10310 to the special Cygnus mode. Some day, perhaps, the differences between
10311 Cygnus trees and GNU trees will disappear (for instance, as GCC is made
10312 more standards compliant). At that time the special Cygnus mode will be
10317 @chapter When Automake Isn't Enough
10319 In some situations, where Automake is not up to one task, one has to
10320 resort to handwritten rules or even handwritten @file{Makefile}s.
10323 * Extending:: Adding new rules or overriding existing ones.
10324 * Third-Party Makefiles:: Integrating Non-Automake @file{Makefile}s.
10328 @section Extending Automake Rules
10330 With some minor exceptions (for example @code{_PROGRAMS} variables,
10331 @code{TESTS}, or @code{XFAIL_TESTS}) being rewritten to append
10332 @samp{$(EXEEXT)}), the contents of a @file{Makefile.am} is copied to
10333 @file{Makefile.in} verbatim.
10335 @cindex copying semantics
10337 These copying semantics mean that many problems can be worked around
10338 by simply adding some @command{make} variables and rules to
10339 @file{Makefile.am}. Automake will ignore these additions.
10341 @cindex conflicting definitions
10342 @cindex rules, conflicting
10343 @cindex variables, conflicting
10344 @cindex definitions, conflicts
10346 Since a @file{Makefile.in} is built from data gathered from three
10347 different places (@file{Makefile.am}, @file{configure.ac}, and
10348 @command{automake} itself), it is possible to have conflicting
10349 definitions of rules or variables. When building @file{Makefile.in}
10350 the following priorities are respected by @command{automake} to ensure
10351 the user always has the last word:
10355 User defined variables in @file{Makefile.am} have priority over
10356 variables @code{AC_SUBST}ed from @file{configure.ac}, and
10357 @code{AC_SUBST}ed variables have priority over
10358 @command{automake}-defined variables.
10360 As far as rules are concerned, a user-defined rule overrides any
10361 @command{automake}-defined rule for the same target.
10364 @cindex overriding rules
10365 @cindex overriding semantics
10366 @cindex rules, overriding
10368 These overriding semantics make it possible to fine tune some default
10369 settings of Automake, or replace some of its rules. Overriding
10370 Automake rules is often inadvisable, particularly in the topmost
10371 directory of a package with subdirectories. The @option{-Woverride}
10372 option (@pxref{Invoking Automake}) comes in handy to catch overridden
10375 Note that Automake does not make any distinction between rules with
10376 commands and rules that only specify dependencies. So it is not
10377 possible to append new dependencies to an @command{automake}-defined
10378 target without redefining the entire rule.
10380 @cindex @option{-local} targets
10381 @cindex local targets
10383 However, various useful targets have a @samp{-local} version you can
10384 specify in your @file{Makefile.am}. Automake will supplement the
10385 standard target with these user-supplied targets.
10390 @trindex info-local
10398 @trindex html-local
10400 @trindex check-local
10402 @trindex install-data
10403 @trindex install-data-local
10404 @trindex install-dvi
10405 @trindex install-dvi-local
10406 @trindex install-exec
10407 @trindex install-exec-local
10408 @trindex install-html
10409 @trindex install-html-local
10410 @trindex install-info
10411 @trindex install-info-local
10412 @trindex install-pdf
10413 @trindex install-pdf-local
10414 @trindex install-ps
10415 @trindex install-ps-local
10417 @trindex uninstall-local
10418 @trindex mostlyclean
10419 @trindex mostlyclean-local
10421 @trindex clean-local
10423 @trindex distclean-local
10424 @trindex installdirs
10425 @trindex installdirs-local
10426 @trindex installcheck
10427 @trindex installcheck-local
10429 The targets that support a local version are @code{all}, @code{info},
10430 @code{dvi}, @code{ps}, @code{pdf}, @code{html}, @code{check},
10431 @code{install-data}, @code{install-dvi}, @code{install-exec},
10432 @code{install-html}, @code{install-info}, @code{install-pdf},
10433 @code{install-ps}, @code{uninstall}, @code{installdirs},
10434 @code{installcheck} and the various @code{clean} targets
10435 (@code{mostlyclean}, @code{clean}, @code{distclean}, and
10436 @code{maintainer-clean}).
10438 Note that there are no @code{uninstall-exec-local} or
10439 @code{uninstall-data-local} targets; just use @code{uninstall-local}.
10440 It doesn't make sense to uninstall just data or just executables.
10442 For instance, here is one way to erase a subdirectory during
10443 @samp{make clean} (@pxref{Clean}).
10450 You may be tempted to use @code{install-data-local} to install a file
10451 to some hard-coded location, but you should avoid this
10452 (@pxref{Hard-Coded Install Paths}).
10454 With the @code{-local} targets, there is no particular guarantee of
10455 execution order; typically, they are run early, but with parallel
10456 make, there is no way to be sure of that.
10458 @cindex @option{-hook} targets
10459 @cindex hook targets
10460 @trindex install-data-hook
10461 @trindex install-exec-hook
10462 @trindex uninstall-hook
10465 In contrast, some rules also have a way to run another rule, called a
10466 @dfn{hook}; hooks are always executed after the main rule's work is done.
10467 The hook is named after the principal target, with @samp{-hook} appended.
10468 The targets allowing hooks are @code{install-data},
10469 @code{install-exec}, @code{uninstall}, @code{dist}, and
10472 For instance, here is how to create a hard link to an installed program:
10476 ln $(DESTDIR)$(bindir)/program$(EXEEXT) \
10477 $(DESTDIR)$(bindir)/proglink$(EXEEXT)
10480 Although cheaper and more portable than symbolic links, hard links
10481 will not work everywhere (for instance, OS/2 does not have
10482 @command{ln}). Ideally you should fall back to @samp{cp -p} when
10483 @command{ln} does not work. An easy way, if symbolic links are
10484 acceptable to you, is to add @code{AC_PROG_LN_S} to
10485 @file{configure.ac} (@pxref{Particular Programs, , Particular Program
10486 Checks, autoconf, The Autoconf Manual}) and use @samp{$(LN_S)} in
10487 @file{Makefile.am}.
10489 @cindex versioned binaries, installing
10490 @cindex installing versioned binaries
10491 @cindex @code{LN_S} example
10492 For instance, here is how you could install a versioned copy of a
10493 program using @samp{$(LN_S)}:
10495 @c Keep in sync with insthook.test
10498 cd $(DESTDIR)$(bindir) && \
10499 mv -f prog$(EXEEXT) prog-$(VERSION)$(EXEEXT) && \
10500 $(LN_S) prog-$(VERSION)$(EXEEXT) prog$(EXEEXT)
10503 Note that we rename the program so that a new version will erase the
10504 symbolic link, not the real binary. Also we @command{cd} into the
10505 destination directory in order to create relative links.
10507 When writing @code{install-exec-hook} or @code{install-data-hook},
10508 please bear in mind that the exec/data distinction is based on the
10509 installation directory, not on the primary used (@pxref{The Two Parts of
10511 @c Keep in sync with primary-prefix-couples-documented-valid.test.
10512 So a @code{foo_SCRIPTS} will be installed by
10513 @code{install-data}, and a @code{barexec_SCRIPTS} will be installed by
10514 @code{install-exec}. You should define your hooks consequently.
10516 @c FIXME should include discussion of variables you can use in these
10519 @node Third-Party Makefiles
10520 @section Third-Party @file{Makefile}s
10522 @cindex Third-party packages, interfacing with
10523 @cindex Interfacing with third-party packages
10525 In most projects all @file{Makefile}s are generated by Automake. In
10526 some cases, however, projects need to embed subdirectories with
10527 handwritten @file{Makefile}s. For instance, one subdirectory could be
10528 a third-party project with its own build system, not using Automake.
10530 It is possible to list arbitrary directories in @code{SUBDIRS} or
10531 @code{DIST_SUBDIRS} provided each of these directories has a
10532 @file{Makefile} that recognizes all the following recursive targets.
10534 @cindex recursive targets and third-party @file{Makefile}s
10535 When a user runs one of these targets, that target is run recursively
10536 in all subdirectories. This is why it is important that even
10537 third-party @file{Makefile}s support them.
10541 Compile the entire package. This is the default target in
10542 Automake-generated @file{Makefile}s, but it does not need to be the
10543 default in third-party @file{Makefile}s.
10548 @vindex top_distdir
10549 Copy files to distribute into @samp{$(distdir)}, before a tarball is
10550 constructed. Of course this target is not required if the
10551 @option{no-dist} option (@pxref{Options}) is used.
10553 The variables @samp{$(top_distdir)} and @samp{$(distdir)}
10554 (@pxref{The dist Hook}) will be passed from the outer package to the subpackage
10555 when the @code{distdir} target is invoked. These two variables have
10556 been adjusted for the directory that is being recursed into, so they
10560 @itemx install-data
10561 @itemx install-exec
10563 Install or uninstall files (@pxref{Install}).
10566 @itemx install-html
10567 @itemx install-info
10570 Install only some specific documentation format (@pxref{Texinfo}).
10573 Create install directories, but do not install any files.
10576 @itemx installcheck
10577 Check the package (@pxref{Tests}).
10582 @itemx maintainer-clean
10583 Cleaning rules (@pxref{Clean}).
10590 Build the documentation in various formats (@pxref{Texinfo}).
10594 Build @file{TAGS} and @file{CTAGS} (@pxref{Tags}).
10597 If you have ever used Gettext in a project, this is a good example of
10598 how third-party @file{Makefile}s can be used with Automake. The
10599 @file{Makefile}s @command{gettextize} puts in the @file{po/} and
10600 @file{intl/} directories are handwritten @file{Makefile}s that
10601 implement all these targets. That way they can be added to
10602 @code{SUBDIRS} in Automake packages.
10604 Directories that are only listed in @code{DIST_SUBDIRS} but not in
10605 @code{SUBDIRS} need only the @code{distclean},
10606 @code{maintainer-clean}, and @code{distdir} rules (@pxref{Conditional
10609 Usually, many of these rules are irrelevant to the third-party
10610 subproject, but they are required for the whole package to work. It's
10611 OK to have a rule that does nothing, so if you are integrating a
10612 third-party project with no documentation or tag support, you could
10613 simply augment its @file{Makefile} as follows:
10616 EMPTY_AUTOMAKE_TARGETS = dvi pdf ps info html tags ctags
10617 .PHONY: $(EMPTY_AUTOMAKE_TARGETS)
10618 $(EMPTY_AUTOMAKE_TARGETS):
10621 Another aspect of integrating third-party build systems is whether
10622 they support VPATH builds (@pxref{VPATH Builds}). Obviously if the
10623 subpackage does not support VPATH builds the whole package will not
10624 support VPATH builds. This in turns means that @samp{make distcheck}
10625 will not work, because it relies on VPATH builds. Some people can
10626 live without this (actually, many Automake users have never heard of
10627 @samp{make distcheck}). Other people may prefer to revamp the
10628 existing @file{Makefile}s to support VPATH@. Doing so does not
10629 necessarily require Automake, only Autoconf is needed (@pxref{Build
10630 Directories, , Build Directories, autoconf, The Autoconf Manual}).
10631 The necessary substitutions: @samp{@@srcdir@@}, @samp{@@top_srcdir@@},
10632 and @samp{@@top_builddir@@} are defined by @file{configure} when it
10633 processes a @file{Makefile} (@pxref{Preset Output Variables, , Preset
10634 Output Variables, autoconf, The Autoconf Manual}), they are not
10635 computed by the Makefile like the aforementioned @samp{$(distdir)} and
10636 @samp{$(top_distdir)} variables.
10638 It is sometimes inconvenient to modify a third-party @file{Makefile}
10639 to introduce the above required targets. For instance, one may want to
10640 keep the third-party sources untouched to ease upgrades to new
10643 @cindex @file{GNUmakefile} including @file{Makefile}
10644 Here are two other ideas. If GNU make is assumed, one possibility is
10645 to add to that subdirectory a @file{GNUmakefile} that defines the
10646 required targets and includes the third-party @file{Makefile}. For
10647 this to work in VPATH builds, @file{GNUmakefile} must lie in the build
10648 directory; the easiest way to do this is to write a
10649 @file{GNUmakefile.in} instead, and have it processed with
10650 @code{AC_CONFIG_FILES} from the outer package. For example if we
10651 assume @file{Makefile} defines all targets except the documentation
10652 targets, and that the @code{check} target is actually called
10653 @code{test}, we could write @file{GNUmakefile} (or
10654 @file{GNUmakefile.in}) like this:
10657 # First, include the real Makefile
10659 # Then, define the other targets needed by Automake Makefiles.
10660 .PHONY: dvi pdf ps info html check
10661 dvi pdf ps info html:
10665 @cindex Proxy @file{Makefile} for third-party packages
10666 A similar idea that does not use @code{include} is to write a proxy
10667 @file{Makefile} that dispatches rules to the real @file{Makefile},
10668 either with @samp{$(MAKE) -f Makefile.real $(AM_MAKEFLAGS) target} (if
10669 it's OK to rename the original @file{Makefile}) or with @samp{cd
10670 subdir && $(MAKE) $(AM_MAKEFLAGS) target} (if it's OK to store the
10671 subdirectory project one directory deeper). The good news is that
10672 this proxy @file{Makefile} can be generated with Automake. All we
10673 need are @option{-local} targets (@pxref{Extending}) that perform the
10674 dispatch. Of course the other Automake features are available, so you
10675 could decide to let Automake perform distribution or installation.
10676 Here is a possible @file{Makefile.am}:
10680 cd subdir && $(MAKE) $(AM_MAKEFLAGS) all
10682 cd subdir && $(MAKE) $(AM_MAKEFLAGS) test
10684 cd subdir && $(MAKE) $(AM_MAKEFLAGS) clean
10686 # Assuming the package knows how to install itself
10687 install-data-local:
10688 cd subdir && $(MAKE) $(AM_MAKEFLAGS) install-data
10689 install-exec-local:
10690 cd subdir && $(MAKE) $(AM_MAKEFLAGS) install-exec
10692 cd subdir && $(MAKE) $(AM_MAKEFLAGS) uninstall
10694 # Distribute files from here.
10695 EXTRA_DIST = subdir/Makefile subdir/program.c ...
10698 Pushing this idea to the extreme, it is also possible to ignore the
10699 subproject build system and build everything from this proxy
10700 @file{Makefile.am}. This might sound very sensible if you need VPATH
10701 builds but the subproject does not support them.
10704 @chapter Distributing @file{Makefile.in}s
10706 Automake places no restrictions on the distribution of the resulting
10707 @file{Makefile.in}s. We still encourage software authors to
10708 distribute their work under terms like those of the GPL, but doing so
10709 is not required to use Automake.
10711 Some of the files that can be automatically installed via the
10712 @option{--add-missing} switch do fall under the GPL@. However, these also
10713 have a special exception allowing you to distribute them with your
10714 package, regardless of the licensing you choose.
10717 @node API Versioning
10718 @chapter Automake API Versioning
10720 New Automake releases usually include bug fixes and new features.
10721 Unfortunately they may also introduce new bugs and incompatibilities.
10722 This makes four reasons why a package may require a particular Automake
10725 Things get worse when maintaining a large tree of packages, each one
10726 requiring a different version of Automake. In the past, this meant that
10727 any developer (and sometimes users) had to install several versions of
10728 Automake in different places, and switch @samp{$PATH} appropriately for
10731 Starting with version 1.6, Automake installs versioned binaries. This
10732 means you can install several versions of Automake in the same
10733 @samp{$prefix}, and can select an arbitrary Automake version by running
10734 @command{automake-1.6} or @command{automake-1.7} without juggling with
10735 @samp{$PATH}. Furthermore, @file{Makefile}'s generated by Automake 1.6
10736 will use @command{automake-1.6} explicitly in their rebuild rules.
10738 The number @samp{1.6} in @command{automake-1.6} is Automake's API version,
10739 not Automake's version. If a bug fix release is made, for instance
10740 Automake 1.6.1, the API version will remain 1.6. This means that a
10741 package that works with Automake 1.6 should also work with 1.6.1; after
10742 all, this is what people expect from bug fix releases.
10744 If your package relies on a feature or a bug fix introduced in
10745 a release, you can pass this version as an option to Automake to ensure
10746 older releases will not be used. For instance, use this in your
10747 @file{configure.ac}:
10750 AM_INIT_AUTOMAKE([1.6.1]) dnl Require Automake 1.6.1 or better.
10754 or, in a particular @file{Makefile.am}:
10757 AUTOMAKE_OPTIONS = 1.6.1 # Require Automake 1.6.1 or better.
10761 Automake will print an error message if its version is
10762 older than the requested version.
10765 @heading What is in the API
10767 Automake's programming interface is not easy to define. Basically it
10768 should include at least all @strong{documented} variables and targets
10769 that a @file{Makefile.am} author can use, any behavior associated with
10770 them (e.g., the places where @samp{-hook}'s are run), the command line
10771 interface of @command{automake} and @command{aclocal}, @dots{}
10773 @heading What is not in the API
10775 Every undocumented variable, target, or command line option, is not part
10776 of the API@. You should avoid using them, as they could change from one
10777 version to the other (even in bug fix releases, if this helps to fix a
10780 If it turns out you need to use such an undocumented feature, contact
10781 @email{automake@@gnu.org} and try to get it documented and exercised by
10785 @chapter Upgrading a Package to a Newer Automake Version
10787 Automake maintains three kind of files in a package.
10790 @item @file{aclocal.m4}
10791 @item @file{Makefile.in}s
10792 @item auxiliary tools like @file{install-sh} or @file{py-compile}
10795 @file{aclocal.m4} is generated by @command{aclocal} and contains some
10796 Automake-supplied M4 macros. Auxiliary tools are installed by
10797 @samp{automake --add-missing} when needed. @file{Makefile.in}s are
10798 built from @file{Makefile.am} by @command{automake}, and rely on the
10799 definitions of the M4 macros put in @file{aclocal.m4} as well as the
10800 behavior of the auxiliary tools installed.
10802 Because all these files are closely related, it is important to
10803 regenerate all of them when upgrading to a newer Automake release.
10804 The usual way to do that is
10807 aclocal # with any option needed (such a -I m4)
10809 automake --add-missing --force-missing
10813 or more conveniently:
10819 The use of @option{--force-missing} ensures that auxiliary tools will be
10820 overridden by new versions (@pxref{Invoking Automake}).
10822 It is important to regenerate all these files each time Automake is
10823 upgraded, even between bug fixes releases. For instance, it is not
10824 unusual for a bug fix to involve changes to both the rules generated
10825 in @file{Makefile.in} and the supporting M4 macros copied to
10828 Presently @command{automake} is able to diagnose situations where
10829 @file{aclocal.m4} has been generated with another version of
10830 @command{aclocal}. However it never checks whether auxiliary scripts
10831 are up-to-date. In other words, @command{automake} will tell you when
10832 @command{aclocal} needs to be rerun, but it will never diagnose a
10833 missing @option{--force-missing}.
10835 Before upgrading to a new major release, it is a good idea to read the
10836 file @file{NEWS}. This file lists all changes between releases: new
10837 features, obsolete constructs, known incompatibilities, and
10841 @chapter Frequently Asked Questions about Automake
10843 This chapter covers some questions that often come up on the mailing
10847 * CVS:: CVS and generated files
10848 * maintainer-mode:: missing and AM_MAINTAINER_MODE
10849 * Wildcards:: Why doesn't Automake support wildcards?
10850 * Limitations on File Names:: Limitations on source and installed file names
10851 * distcleancheck:: Files left in build directory after distclean
10852 * Flag Variables Ordering:: CFLAGS vs.@: AM_CFLAGS vs.@: mumble_CFLAGS
10853 * Renamed Objects:: Why are object files sometimes renamed?
10854 * Per-Object Flags:: How to simulate per-object flags?
10855 * Multiple Outputs:: Writing rules for tools with many output files
10856 * Hard-Coded Install Paths:: Installing to hard-coded locations
10857 * Debugging Make Rules:: Strategies when things don't work as expected
10858 * Reporting Bugs:: Feedback on bugs and feature requests
10862 @section CVS and generated files
10864 @subheading Background: distributed generated Files
10865 @cindex generated files, distributed
10866 @cindex rebuild rules
10868 Packages made with Autoconf and Automake ship with some generated
10869 files like @file{configure} or @file{Makefile.in}. These files were
10870 generated on the developer's host and are distributed so that
10871 end-users do not have to install the maintainer tools required to
10872 rebuild them. Other generated files like Lex scanners, Yacc parsers,
10873 or Info documentation, are usually distributed on similar grounds.
10875 Automake outputs rules in @file{Makefile}s to rebuild these files. For
10876 instance, @command{make} will run @command{autoconf} to rebuild
10877 @file{configure} whenever @file{configure.ac} is changed. This makes
10878 development safer by ensuring a @file{configure} is never out-of-date
10879 with respect to @file{configure.ac}.
10881 As generated files shipped in packages are up-to-date, and because
10882 @command{tar} preserves times-tamps, these rebuild rules are not
10883 triggered when a user unpacks and builds a package.
10885 @subheading Background: CVS and Timestamps
10886 @cindex timestamps and CVS
10887 @cindex CVS and timestamps
10889 Unless you use CVS keywords (in which case files must be updated at
10890 commit time), CVS preserves timestamp during @samp{cvs commit} and
10891 @samp{cvs import -d} operations.
10893 When you check out a file using @samp{cvs checkout} its timestamp is
10894 set to that of the revision that is being checked out.
10896 However, during @command{cvs update}, files will have the date of the
10897 update, not the original timestamp of this revision. This is meant to
10898 make sure that @command{make} notices sources files have been updated.
10900 This timestamp shift is troublesome when both sources and generated
10901 files are kept under CVS@. Because CVS processes files in lexical
10902 order, @file{configure.ac} will appear newer than @file{configure}
10903 after a @command{cvs update} that updates both files, even if
10904 @file{configure} was newer than @file{configure.ac} when it was
10905 checked in. Calling @command{make} will then trigger a spurious rebuild
10906 of @file{configure}.
10908 @subheading Living with CVS in Autoconfiscated Projects
10909 @cindex CVS and generated files
10910 @cindex generated files and CVS
10912 There are basically two clans amongst maintainers: those who keep all
10913 distributed files under CVS, including generated files, and those who
10914 keep generated files @emph{out} of CVS.
10916 @subsubheading All Files in CVS
10920 The CVS repository contains all distributed files so you know exactly
10921 what is distributed, and you can checkout any prior version entirely.
10924 Maintainers can see how generated files evolve (for instance, you can
10925 see what happens to your @file{Makefile.in}s when you upgrade Automake
10926 and make sure they look OK).
10929 Users do not need the autotools to build a checkout of the project, it
10930 works just like a released tarball.
10933 If users use @command{cvs update} to update their copy, instead of
10934 @command{cvs checkout} to fetch a fresh one, timestamps will be
10935 inaccurate. Some rebuild rules will be triggered and attempt to
10936 run developer tools such as @command{autoconf} or @command{automake}.
10938 Actually, calls to such tools are all wrapped into a call to the
10939 @command{missing} script discussed later (@pxref{maintainer-mode}).
10940 @command{missing} will take care of fixing the timestamps when these
10941 tools are not installed, so that the build can continue.
10944 In distributed development, developers are likely to have different
10945 version of the maintainer tools installed. In this case rebuilds
10946 triggered by timestamp lossage will lead to spurious changes
10947 to generated files. There are several solutions to this:
10951 All developers should use the same versions, so that the rebuilt files
10952 are identical to files in CVS@. (This starts to be difficult when each
10953 project you work on uses different versions.)
10955 Or people use a script to fix the timestamp after a checkout (the GCC
10956 folks have such a script).
10958 Or @file{configure.ac} uses @code{AM_MAINTAINER_MODE}, which will
10959 disable all these rebuild rules by default. This is further discussed
10960 in @ref{maintainer-mode}.
10964 Although we focused on spurious rebuilds, the converse can also
10965 happen. CVS's timestamp handling can also let you think an
10966 out-of-date file is up-to-date.
10968 For instance, suppose a developer has modified @file{Makefile.am} and
10969 has rebuilt @file{Makefile.in}, and then decides to do a last-minute
10970 change to @file{Makefile.am} right before checking in both files
10971 (without rebuilding @file{Makefile.in} to account for the change).
10973 This last change to @file{Makefile.am} makes the copy of
10974 @file{Makefile.in} out-of-date. Since CVS processes files
10975 alphabetically, when another developer @samp{cvs update}s his or her
10976 tree, @file{Makefile.in} will happen to be newer than
10977 @file{Makefile.am}. This other developer will not see that
10978 @file{Makefile.in} is out-of-date.
10982 @subsubheading Generated Files out of CVS
10984 One way to get CVS and @command{make} working peacefully is to never
10985 store generated files in CVS, i.e., do not CVS-control files that
10986 are @file{Makefile} targets (also called @emph{derived} files).
10988 This way developers are not annoyed by changes to generated files. It
10989 does not matter if they all have different versions (assuming they are
10990 compatible, of course). And finally, timestamps are not lost, changes
10991 to sources files can't be missed as in the
10992 @file{Makefile.am}/@file{Makefile.in} example discussed earlier.
10994 The drawback is that the CVS repository is not an exact copy of what
10995 is distributed and that users now need to install various development
10996 tools (maybe even specific versions) before they can build a checkout.
10997 But, after all, CVS's job is versioning, not distribution.
10999 Allowing developers to use different versions of their tools can also
11000 hide bugs during distributed development. Indeed, developers will be
11001 using (hence testing) their own generated files, instead of the
11002 generated files that will be released actually. The developer who
11003 prepares the tarball might be using a version of the tool that
11004 produces bogus output (for instance a non-portable C file), something
11005 other developers could have noticed if they weren't using their own
11006 versions of this tool.
11008 @subheading Third-party Files
11009 @cindex CVS and third-party files
11010 @cindex third-party files and CVS
11012 Another class of files not discussed here (because they do not cause
11013 timestamp issues) are files that are shipped with a package, but
11014 maintained elsewhere. For instance, tools like @command{gettextize}
11015 and @command{autopoint} (from Gettext) or @command{libtoolize} (from
11016 Libtool), will install or update files in your package.
11018 These files, whether they are kept under CVS or not, raise similar
11019 concerns about version mismatch between developers' tools. The
11020 Gettext manual has a section about this, see @ref{CVS Issues, CVS
11021 Issues, Integrating with CVS, gettext, GNU gettext tools}.
11023 @node maintainer-mode
11024 @section @command{missing} and @code{AM_MAINTAINER_MODE}
11026 @subheading @command{missing}
11027 @cindex @command{missing}, purpose
11029 The @command{missing} script is a wrapper around several maintainer
11030 tools, designed to warn users if a maintainer tool is required but
11031 missing. Typical maintainer tools are @command{autoconf},
11032 @command{automake}, @command{bison}, etc. Because file generated by
11033 these tools are shipped with the other sources of a package, these
11034 tools shouldn't be required during a user build and they are not
11035 checked for in @file{configure}.
11037 However, if for some reason a rebuild rule is triggered and involves a
11038 missing tool, @command{missing} will notice it and warn the user.
11039 Besides the warning, when a tool is missing, @command{missing} will
11040 attempt to fix timestamps in a way that allows the build to continue.
11041 For instance, @command{missing} will touch @file{configure} if
11042 @command{autoconf} is not installed. When all distributed files are
11043 kept under version control, this feature of @command{missing} allows a
11044 user @emph{with no maintainer tools} to build a package off its version
11045 control repository, bypassing any timestamp inconsistency (implied by
11046 e.g.@: @samp{cvs update} or @samp{git clone}).
11048 If the required tool is installed, @command{missing} will run it and
11049 won't attempt to continue after failures. This is correct during
11050 development: developers love fixing failures. However, users with
11051 wrong versions of maintainer tools may get an error when the rebuild
11052 rule is spuriously triggered, halting the build. This failure to let
11053 the build continue is one of the arguments of the
11054 @code{AM_MAINTAINER_MODE} advocates.
11056 @subheading @code{AM_MAINTAINER_MODE}
11057 @cindex @code{AM_MAINTAINER_MODE}, purpose
11058 @acindex AM_MAINTAINER_MODE
11060 @code{AM_MAINTAINER_MODE} allows you to choose whether the so called
11061 "rebuild rules" should be enabled or disabled. With
11062 @code{AM_MAINTAINER_MODE([enable])}, they are enabled by default,
11063 otherwise they are disabled by default. In the latter case, if
11064 you have @code{AM_MAINTAINER_MODE} in @file{configure.ac}, and run
11065 @samp{./configure && make}, then @command{make} will *never* attempt to
11066 rebuild @file{configure}, @file{Makefile.in}s, Lex or Yacc outputs, etc.
11067 I.e., this disables build rules for files that are usually distributed
11068 and that users should normally not have to update.
11070 The user can override the default setting by passing either
11071 @samp{--enable-maintainer-mode} or @samp{--disable-maintainer-mode}
11072 to @command{configure}.
11074 People use @code{AM_MAINTAINER_MODE} either because they do not want their
11075 users (or themselves) annoyed by timestamps lossage (@pxref{CVS}), or
11076 because they simply can't stand the rebuild rules and prefer running
11077 maintainer tools explicitly.
11079 @code{AM_MAINTAINER_MODE} also allows you to disable some custom build
11080 rules conditionally. Some developers use this feature to disable
11081 rules that need exotic tools that users may not have available.
11083 Several years ago Fran@,{c}ois Pinard pointed out several arguments
11084 against this @code{AM_MAINTAINER_MODE} macro. Most of them relate to
11085 insecurity. By removing dependencies you get non-dependable builds:
11086 changes to sources files can have no effect on generated files and this
11087 can be very confusing when unnoticed. He adds that security shouldn't
11088 be reserved to maintainers (what @option{--enable-maintainer-mode}
11089 suggests), on the contrary. If one user has to modify a
11090 @file{Makefile.am}, then either @file{Makefile.in} should be updated
11091 or a warning should be output (this is what Automake uses
11092 @command{missing} for) but the last thing you want is that nothing
11093 happens and the user doesn't notice it (this is what happens when
11094 rebuild rules are disabled by @code{AM_MAINTAINER_MODE}).
11096 Jim Meyering, the inventor of the @code{AM_MAINTAINER_MODE} macro was
11097 swayed by Fran@,{c}ois's arguments, and got rid of
11098 @code{AM_MAINTAINER_MODE} in all of his packages.
11100 Still many people continue to use @code{AM_MAINTAINER_MODE}, because
11101 it helps them working on projects where all files are kept under version
11102 control, and because @command{missing} isn't enough if you have the
11103 wrong version of the tools.
11107 @section Why doesn't Automake support wildcards?
11110 Developers are lazy. They would often like to use wildcards in
11111 @file{Makefile.am}s, so that they would not need to remember to
11112 update @file{Makefile.am}s every time they add, delete, or rename
11115 There are several objections to this:
11118 When using CVS (or similar) developers need to remember they have to
11119 run @samp{cvs add} or @samp{cvs rm} anyway. Updating
11120 @file{Makefile.am} accordingly quickly becomes a reflex.
11122 Conversely, if your application doesn't compile
11123 because you forgot to add a file in @file{Makefile.am}, it will help
11124 you remember to @samp{cvs add} it.
11127 Using wildcards makes it easy to distribute files by mistake. For
11128 instance, some code a developer is experimenting with (a test case,
11129 say) that should not be part of the distribution.
11132 Using wildcards it's easy to omit some files by mistake. For
11133 instance, one developer creates a new file, uses it in many places,
11134 but forgets to commit it. Another developer then checks out the
11135 incomplete project and is able to run @samp{make dist} successfully,
11136 even though a file is missing. By listing files, @samp{make dist}
11137 @emph{will} complain.
11140 Wildcards are not portable to some non-GNU @command{make} implementations,
11141 e.g., NetBSD @command{make} will not expand globs such as @samp{*} in
11142 prerequisites of a target.
11145 Finally, it's really hard to @emph{forget} to add a file to
11146 @file{Makefile.am}: files that are not listed in @file{Makefile.am} are
11147 not compiled or installed, so you can't even test them.
11150 Still, these are philosophical objections, and as such you may disagree,
11151 or find enough value in wildcards to dismiss all of them. Before you
11152 start writing a patch against Automake to teach it about wildcards,
11153 let's see the main technical issue: portability.
11155 Although @samp{$(wildcard ...)} works with GNU @command{make}, it is
11156 not portable to other @command{make} implementations.
11158 The only way Automake could support @command{$(wildcard ...)} is by
11159 expending @command{$(wildcard ...)} when @command{automake} is run.
11160 The resulting @file{Makefile.in}s would be portable since they would
11161 list all files and not use @samp{$(wildcard ...)}. However that
11162 means developers would need to remember to run @command{automake} each
11163 time they add, delete, or rename files.
11165 Compared to editing @file{Makefile.am}, this is a very small gain. Sure,
11166 it's easier and faster to type @samp{automake; make} than to type
11167 @samp{emacs Makefile.am; make}. But nobody bothered enough to write a
11168 patch to add support for this syntax. Some people use scripts to
11169 generate file lists in @file{Makefile.am} or in separate
11170 @file{Makefile} fragments.
11172 Even if you don't care about portability, and are tempted to use
11173 @samp{$(wildcard ...)} anyway because you target only GNU Make, you
11174 should know there are many places where Automake needs to know exactly
11175 which files should be processed. As Automake doesn't know how to
11176 expand @samp{$(wildcard ...)}, you cannot use it in these places.
11177 @samp{$(wildcard ...)} is a black box comparable to @code{AC_SUBST}ed
11178 variables as far Automake is concerned.
11180 You can get warnings about @samp{$(wildcard ...}) constructs using the
11181 @option{-Wportability} flag.
11183 @node Limitations on File Names
11184 @section Limitations on File Names
11185 @cindex file names, limitations on
11187 Automake attempts to support all kinds of file names, even those that
11188 contain unusual characters or are unusually long. However, some
11189 limitations are imposed by the underlying operating system and tools.
11191 Most operating systems prohibit the use of the null byte in file
11192 names, and reserve @samp{/} as a directory separator. Also, they
11193 require that file names are properly encoded for the user's locale.
11194 Automake is subject to these limits.
11196 Portable packages should limit themselves to POSIX file
11197 names. These can contain ASCII letters and digits,
11198 @samp{_}, @samp{.}, and @samp{-}. File names consist of components
11199 separated by @samp{/}. File name components cannot begin with
11202 Portable POSIX file names cannot contain components that exceed a
11203 14-byte limit, but nowadays it's normally safe to assume the
11204 more-generous XOPEN limit of 255 bytes. POSIX
11205 limits file names to 255 bytes (XOPEN allows 1023 bytes),
11206 but you may want to limit a source tarball to file names of 99 bytes
11207 to avoid interoperability problems with old versions of @command{tar}.
11209 If you depart from these rules (e.g., by using non-ASCII
11210 characters in file names, or by using lengthy file names), your
11211 installers may have problems for reasons unrelated to Automake.
11212 However, if this does not concern you, you should know about the
11213 limitations imposed by Automake itself. These limitations are
11214 undesirable, but some of them seem to be inherent to underlying tools
11215 like Autoconf, Make, M4, and the shell. They fall into three
11216 categories: install directories, build directories, and file names.
11218 The following characters:
11221 @r{newline} " # $ ' `
11224 should not appear in the names of install directories. For example,
11225 the operand of @command{configure}'s @option{--prefix} option should
11226 not contain these characters.
11228 Build directories suffer the same limitations as install directories,
11229 and in addition should not contain the following characters:
11235 For example, the full name of the directory containing the source
11236 files should not contain these characters.
11238 Source and installation file names like @file{main.c} are limited even
11239 further: they should conform to the POSIX/XOPEN
11240 rules described above. In addition, if you plan to port to
11241 non-POSIX environments, you should avoid file names that
11242 differ only in case (e.g., @file{makefile} and @file{Makefile}).
11243 Nowadays it is no longer worth worrying about the 8.3 limits of
11246 @node distcleancheck
11247 @section Files left in build directory after distclean
11248 @cindex @code{distclean}, diagnostic
11249 @cindex @samp{make distclean}, diagnostic
11250 @cindex dependencies and distributed files
11252 @trindex distcleancheck
11254 This is a diagnostic you might encounter while running @samp{make
11257 As explained in @ref{Checking the Distribution}, @samp{make distcheck}
11258 attempts to build and check your package for errors like this one.
11260 @samp{make distcheck} will perform a @code{VPATH} build of your
11261 package (@pxref{VPATH Builds}), and then call @samp{make distclean}.
11262 Files left in the build directory after @samp{make distclean} has run
11263 are listed after this error.
11265 This diagnostic really covers two kinds of errors:
11269 files that are forgotten by distclean;
11271 distributed files that are erroneously rebuilt.
11274 The former left-over files are not distributed, so the fix is to mark
11275 them for cleaning (@pxref{Clean}), this is obvious and doesn't deserve
11278 The latter bug is not always easy to understand and fix, so let's
11279 proceed with an example. Suppose our package contains a program for
11280 which we want to build a man page using @command{help2man}. GNU
11281 @command{help2man} produces simple manual pages from the @option{--help}
11282 and @option{--version} output of other commands (@pxref{Top, , Overview,
11283 help2man, The Help2man Manual}). Because we don't want to force our
11284 users to install @command{help2man}, we decide to distribute the
11285 generated man page using the following setup.
11288 # This Makefile.am is bogus.
11290 foo_SOURCES = foo.c
11291 dist_man_MANS = foo.1
11293 foo.1: foo$(EXEEXT)
11294 help2man --output=foo.1 ./foo$(EXEEXT)
11297 This will effectively distribute the man page. However,
11298 @samp{make distcheck} will fail with:
11301 ERROR: files left in build directory after distclean:
11305 Why was @file{foo.1} rebuilt? Because although distributed,
11306 @file{foo.1} depends on a non-distributed built file:
11307 @file{foo$(EXEEXT)}. @file{foo$(EXEEXT)} is built by the user, so it
11308 will always appear to be newer than the distributed @file{foo.1}.
11310 @samp{make distcheck} caught an inconsistency in our package. Our
11311 intent was to distribute @file{foo.1} so users do not need to install
11312 @command{help2man}, however since this rule causes this file to be
11313 always rebuilt, users @emph{do} need @command{help2man}. Either we
11314 should ensure that @file{foo.1} is not rebuilt by users, or there is
11315 no point in distributing @file{foo.1}.
11317 More generally, the rule is that distributed files should never depend
11318 on non-distributed built files. If you distribute something
11319 generated, distribute its sources.
11321 One way to fix the above example, while still distributing
11322 @file{foo.1} is to not depend on @file{foo$(EXEEXT)}. For instance,
11323 assuming @command{foo --version} and @command{foo --help} do not
11324 change unless @file{foo.c} or @file{configure.ac} change, we could
11325 write the following @file{Makefile.am}:
11329 foo_SOURCES = foo.c
11330 dist_man_MANS = foo.1
11332 foo.1: foo.c $(top_srcdir)/configure.ac
11333 $(MAKE) $(AM_MAKEFLAGS) foo$(EXEEXT)
11334 help2man --output=foo.1 ./foo$(EXEEXT)
11337 This way, @file{foo.1} will not get rebuilt every time
11338 @file{foo$(EXEEXT)} changes. The @command{make} call makes sure
11339 @file{foo$(EXEEXT)} is up-to-date before @command{help2man}. Another
11340 way to ensure this would be to use separate directories for binaries
11341 and man pages, and set @code{SUBDIRS} so that binaries are built
11344 We could also decide not to distribute @file{foo.1}. In
11345 this case it's fine to have @file{foo.1} dependent upon
11346 @file{foo$(EXEEXT)}, since both will have to be rebuilt.
11347 However it would be impossible to build the package in a
11348 cross-compilation, because building @file{foo.1} involves
11349 an @emph{execution} of @file{foo$(EXEEXT)}.
11351 Another context where such errors are common is when distributed files
11352 are built by tools that are built by the package. The pattern is
11356 distributed-file: built-tools distributed-sources
11361 should be changed to
11364 distributed-file: distributed-sources
11365 $(MAKE) $(AM_MAKEFLAGS) built-tools
11370 or you could choose not to distribute @file{distributed-file}, if
11371 cross-compilation does not matter.
11373 The points made through these examples are worth a summary:
11378 Distributed files should never depend upon non-distributed built
11381 Distributed files should be distributed with all their dependencies.
11383 If a file is @emph{intended} to be rebuilt by users, then there is no point
11384 in distributing it.
11388 @vrindex distcleancheck_listfiles
11389 For desperate cases, it's always possible to disable this check by
11390 setting @code{distcleancheck_listfiles} as documented in @ref{Checking
11392 Make sure you do understand the reason why @samp{make distcheck}
11393 complains before you do this. @code{distcleancheck_listfiles} is a
11394 way to @emph{hide} errors, not to fix them. You can always do better.
11396 @node Flag Variables Ordering
11397 @section Flag Variables Ordering
11398 @cindex Ordering flag variables
11399 @cindex Flag variables, ordering
11402 What is the difference between @code{AM_CFLAGS}, @code{CFLAGS}, and
11403 @code{mumble_CFLAGS}?
11407 Why does @command{automake} output @code{CPPFLAGS} after
11408 @code{AM_CPPFLAGS} on compile lines? Shouldn't it be the converse?
11412 My @file{configure} adds some warning flags into @code{CXXFLAGS}. In
11413 one @file{Makefile.am} I would like to append a new flag, however if I
11414 put the flag into @code{AM_CXXFLAGS} it is prepended to the other
11415 flags, not appended.
11418 @subheading Compile Flag Variables
11419 @cindex Flag Variables, Ordering
11420 @cindex Compile Flag Variables
11421 @cindex @code{AM_CCASFLAGS} and @code{CCASFLAGS}
11422 @cindex @code{AM_CFLAGS} and @code{CFLAGS}
11423 @cindex @code{AM_CPPFLAGS} and @code{CPPFLAGS}
11424 @cindex @code{AM_CXXFLAGS} and @code{CXXFLAGS}
11425 @cindex @code{AM_FCFLAGS} and @code{FCFLAGS}
11426 @cindex @code{AM_FFLAGS} and @code{FFLAGS}
11427 @cindex @code{AM_GCJFLAGS} and @code{GCJFLAGS}
11428 @cindex @code{AM_LDFLAGS} and @code{LDFLAGS}
11429 @cindex @code{AM_LFLAGS} and @code{LFLAGS}
11430 @cindex @code{AM_LIBTOOLFLAGS} and @code{LIBTOOLFLAGS}
11431 @cindex @code{AM_OBJCFLAGS} and @code{OBJCFLAGS}
11432 @cindex @code{AM_RFLAGS} and @code{RFLAGS}
11433 @cindex @code{AM_UPCFLAGS} and @code{UPCFLAGS}
11434 @cindex @code{AM_YFLAGS} and @code{YFLAGS}
11435 @cindex @code{CCASFLAGS} and @code{AM_CCASFLAGS}
11436 @cindex @code{CFLAGS} and @code{AM_CFLAGS}
11437 @cindex @code{CPPFLAGS} and @code{AM_CPPFLAGS}
11438 @cindex @code{CXXFLAGS} and @code{AM_CXXFLAGS}
11439 @cindex @code{FCFLAGS} and @code{AM_FCFLAGS}
11440 @cindex @code{FFLAGS} and @code{AM_FFLAGS}
11441 @cindex @code{GCJFLAGS} and @code{AM_GCJFLAGS}
11442 @cindex @code{LDFLAGS} and @code{AM_LDFLAGS}
11443 @cindex @code{LFLAGS} and @code{AM_LFLAGS}
11444 @cindex @code{LIBTOOLFLAGS} and @code{AM_LIBTOOLFLAGS}
11445 @cindex @code{OBJCFLAGS} and @code{AM_OBJCFLAGS}
11446 @cindex @code{RFLAGS} and @code{AM_RFLAGS}
11447 @cindex @code{UPCFLAGS} and @code{AM_UPCFLAGS}
11448 @cindex @code{YFLAGS} and @code{AM_YFLAGS}
11450 This section attempts to answer all the above questions. We will
11451 mostly discuss @code{CPPFLAGS} in our examples, but actually the
11452 answer holds for all the compile flags used in Automake:
11453 @code{CCASFLAGS}, @code{CFLAGS}, @code{CPPFLAGS}, @code{CXXFLAGS},
11454 @code{FCFLAGS}, @code{FFLAGS}, @code{GCJFLAGS}, @code{LDFLAGS},
11455 @code{LFLAGS}, @code{LIBTOOLFLAGS}, @code{OBJCFLAGS}, @code{RFLAGS},
11456 @code{UPCFLAGS}, and @code{YFLAGS}.
11458 @code{CPPFLAGS}, @code{AM_CPPFLAGS}, and @code{mumble_CPPFLAGS} are
11459 three variables that can be used to pass flags to the C preprocessor
11460 (actually these variables are also used for other languages like C++
11461 or preprocessed Fortran). @code{CPPFLAGS} is the user variable
11462 (@pxref{User Variables}), @code{AM_CPPFLAGS} is the Automake variable,
11463 and @code{mumble_CPPFLAGS} is the variable specific to the
11464 @code{mumble} target (we call this a per-target variable,
11465 @pxref{Program and Library Variables}).
11467 Automake always uses two of these variables when compiling C sources
11468 files. When compiling an object file for the @code{mumble} target,
11469 the first variable will be @code{mumble_CPPFLAGS} if it is defined, or
11470 @code{AM_CPPFLAGS} otherwise. The second variable is always
11473 In the following example,
11476 bin_PROGRAMS = foo bar
11477 foo_SOURCES = xyz.c
11478 bar_SOURCES = main.c
11479 foo_CPPFLAGS = -DFOO
11480 AM_CPPFLAGS = -DBAZ
11484 @file{xyz.o} will be compiled with @samp{$(foo_CPPFLAGS) $(CPPFLAGS)},
11485 (because @file{xyz.o} is part of the @code{foo} target), while
11486 @file{main.o} will be compiled with @samp{$(AM_CPPFLAGS) $(CPPFLAGS)}
11487 (because there is no per-target variable for target @code{bar}).
11489 The difference between @code{mumble_CPPFLAGS} and @code{AM_CPPFLAGS}
11490 being clear enough, let's focus on @code{CPPFLAGS}. @code{CPPFLAGS}
11491 is a user variable, i.e., a variable that users are entitled to modify
11492 in order to compile the package. This variable, like many others,
11493 is documented at the end of the output of @samp{configure --help}.
11495 For instance, someone who needs to add @file{/home/my/usr/include} to
11496 the C compiler's search path would configure a package with
11499 ./configure CPPFLAGS='-I /home/my/usr/include'
11503 and this flag would be propagated to the compile rules of all
11506 It is also not uncommon to override a user variable at
11507 @command{make}-time. Many installers do this with @code{prefix}, but
11508 this can be useful with compiler flags too. For instance, if, while
11509 debugging a C++ project, you need to disable optimization in one
11510 specific object file, you can run something like
11514 make CXXFLAGS=-O0 file.o
11518 The reason @samp{$(CPPFLAGS)} appears after @samp{$(AM_CPPFLAGS)} or
11519 @samp{$(mumble_CPPFLAGS)} in the compile command is that users
11520 should always have the last say. It probably makes more sense if you
11521 think about it while looking at the @samp{CXXFLAGS=-O0} above, which
11522 should supersede any other switch from @code{AM_CXXFLAGS} or
11523 @code{mumble_CXXFLAGS} (and this of course replaces the previous value
11524 of @code{CXXFLAGS}).
11526 You should never redefine a user variable such as @code{CPPFLAGS} in
11527 @file{Makefile.am}. Use @samp{automake -Woverride} to diagnose such
11528 mistakes. Even something like
11531 CPPFLAGS = -DDATADIR=\"$(datadir)\" @@CPPFLAGS@@
11535 is erroneous. Although this preserves @file{configure}'s value of
11536 @code{CPPFLAGS}, the definition of @code{DATADIR} will disappear if a
11537 user attempts to override @code{CPPFLAGS} from the @command{make}
11541 AM_CPPFLAGS = -DDATADIR=\"$(datadir)\"
11545 is all that is needed here if no per-target flags are used.
11547 You should not add options to these user variables within
11548 @file{configure} either, for the same reason. Occasionally you need
11549 to modify these variables to perform a test, but you should reset
11550 their values afterwards. In contrast, it is OK to modify the
11551 @samp{AM_} variables within @file{configure} if you @code{AC_SUBST}
11552 them, but it is rather rare that you need to do this, unless you
11553 really want to change the default definitions of the @samp{AM_}
11554 variables in all @file{Makefile}s.
11556 What we recommend is that you define extra flags in separate
11557 variables. For instance, you may write an Autoconf macro that computes
11558 a set of warning options for the C compiler, and @code{AC_SUBST} them
11559 in @code{WARNINGCFLAGS}; you may also have an Autoconf macro that
11560 determines which compiler and which linker flags should be used to
11561 link with library @file{libfoo}, and @code{AC_SUBST} these in
11562 @code{LIBFOOCFLAGS} and @code{LIBFOOLDFLAGS}. Then, a
11563 @file{Makefile.am} could use these variables as follows:
11566 AM_CFLAGS = $(WARNINGCFLAGS)
11567 bin_PROGRAMS = prog1 prog2
11568 prog1_SOURCES = @dots{}
11569 prog2_SOURCES = @dots{}
11570 prog2_CFLAGS = $(LIBFOOCFLAGS) $(AM_CFLAGS)
11571 prog2_LDFLAGS = $(LIBFOOLDFLAGS)
11574 In this example both programs will be compiled with the flags
11575 substituted into @samp{$(WARNINGCFLAGS)}, and @code{prog2} will
11576 additionally be compiled with the flags required to link with
11579 Note that listing @code{AM_CFLAGS} in a per-target @code{CFLAGS}
11580 variable is a common idiom to ensure that @code{AM_CFLAGS} applies to
11581 every target in a @file{Makefile.in}.
11583 Using variables like this gives you full control over the ordering of
11584 the flags. For instance, if there is a flag in $(WARNINGCFLAGS) that
11585 you want to negate for a particular target, you can use something like
11586 @samp{prog1_CFLAGS = $(AM_CFLAGS) -no-flag}. If all these flags had
11587 been forcefully appended to @code{CFLAGS}, there would be no way to
11588 disable one flag. Yet another reason to leave user variables to
11591 Finally, we have avoided naming the variable of the example
11592 @code{LIBFOO_LDFLAGS} (with an underscore) because that would cause
11593 Automake to think that this is actually a per-target variable (like
11594 @code{mumble_LDFLAGS}) for some non-declared @code{LIBFOO} target.
11596 @subheading Other Variables
11598 There are other variables in Automake that follow similar principles
11599 to allow user options. For instance, Texinfo rules (@pxref{Texinfo})
11600 use @code{MAKEINFOFLAGS} and @code{AM_MAKEINFOFLAGS}. Similarly,
11601 DejaGnu tests (@pxref{DejaGnu Tests}) use @code{RUNTESTDEFAULTFLAGS} and
11602 @code{AM_RUNTESTDEFAULTFLAGS}. The tags and ctags rules
11603 (@pxref{Tags}) use @code{ETAGSFLAGS}, @code{AM_ETAGSFLAGS},
11604 @code{CTAGSFLAGS}, and @code{AM_CTAGSFLAGS}. Java rules
11605 (@pxref{Java}) use @code{JAVACFLAGS} and @code{AM_JAVACFLAGS}. None
11606 of these rules support per-target flags (yet).
11608 To some extent, even @code{AM_MAKEFLAGS} (@pxref{Subdirectories})
11609 obeys this naming scheme. The slight difference is that
11610 @code{MAKEFLAGS} is passed to sub-@command{make}s implicitly by
11611 @command{make} itself.
11613 However you should not think that all variables ending with
11614 @code{FLAGS} follow this convention. For instance,
11615 @code{DISTCHECK_CONFIGURE_FLAGS} (@pxref{Checking the Distribution}) and
11616 @code{ACLOCAL_AMFLAGS} (see @ref{Rebuilding} and @ref{Local Macros}),
11617 are two variables that are only useful to the maintainer and have no
11620 @code{ARFLAGS} (@pxref{A Library}) is usually defined by Automake and
11621 has neither @code{AM_} nor per-target cousin.
11623 Finally you should not think that the existence of a per-target
11624 variable implies the existance of an @code{AM_} variable or of a user
11625 variable. For instance, the @code{mumble_LDADD} per-target variable
11626 overrides the makefile-wide @code{LDADD} variable (which is not a user
11627 variable), and @code{mumble_LIBADD} exists only as a per-target
11628 variable. @xref{Program and Library Variables}.
11631 @node Renamed Objects
11632 @section Why are object files sometimes renamed?
11634 This happens when per-target compilation flags are used. Object
11635 files need to be renamed just in case they would clash with object
11636 files compiled from the same sources, but with different flags.
11637 Consider the following example.
11640 bin_PROGRAMS = true false
11641 true_SOURCES = generic.c
11642 true_CPPFLAGS = -DEXIT_CODE=0
11643 false_SOURCES = generic.c
11644 false_CPPFLAGS = -DEXIT_CODE=1
11648 Obviously the two programs are built from the same source, but it
11649 would be bad if they shared the same object, because @file{generic.o}
11650 cannot be built with both @samp{-DEXIT_CODE=0} @emph{and}
11651 @samp{-DEXIT_CODE=1}. Therefore @command{automake} outputs rules to
11652 build two different objects: @file{true-generic.o} and
11653 @file{false-generic.o}.
11655 @command{automake} doesn't actually look whether source files are
11656 shared to decide if it must rename objects. It will just rename all
11657 objects of a target as soon as it sees per-target compilation flags
11660 It's OK to share object files when per-target compilation flags are not
11661 used. For instance, @file{true} and @file{false} will both use
11662 @file{version.o} in the following example.
11665 AM_CPPFLAGS = -DVERSION=1.0
11666 bin_PROGRAMS = true false
11667 true_SOURCES = true.c version.c
11668 false_SOURCES = false.c version.c
11671 Note that the renaming of objects is also affected by the
11672 @code{_SHORTNAME} variable (@pxref{Program and Library Variables}).
11675 @node Per-Object Flags
11676 @section Per-Object Flags Emulation
11677 @cindex Per-object flags, emulated
11680 One of my source files needs to be compiled with different flags. How
11684 Automake supports per-program and per-library compilation flags (see
11685 @ref{Program and Library Variables} and @ref{Flag Variables
11686 Ordering}). With this you can define compilation flags that apply to
11687 all files compiled for a target. For instance, in
11691 foo_SOURCES = foo.c foo.h bar.c bar.h main.c
11692 foo_CFLAGS = -some -flags
11696 @file{foo-foo.o}, @file{foo-bar.o}, and @file{foo-main.o} will all be
11697 compiled with @samp{-some -flags}. (If you wonder about the names of
11698 these object files, see @ref{Renamed Objects}.) Note that
11699 @code{foo_CFLAGS} gives the flags to use when compiling all the C
11700 sources of the @emph{program} @code{foo}, it has nothing to do with
11701 @file{foo.c} or @file{foo-foo.o} specifically.
11703 What if @file{foo.c} needs to be compiled into @file{foo.o} using some
11704 specific flags, that none of the other files requires? Obviously
11705 per-program flags are not directly applicable here. Something like
11706 per-object flags are expected, i.e., flags that would be used only
11707 when creating @file{foo-foo.o}. Automake does not support that,
11708 however this is easy to simulate using a library that contains only
11709 that object, and compiling this library with per-library flags.
11713 foo_SOURCES = bar.c bar.h main.c
11714 foo_CFLAGS = -some -flags
11715 foo_LDADD = libfoo.a
11716 noinst_LIBRARIES = libfoo.a
11717 libfoo_a_SOURCES = foo.c foo.h
11718 libfoo_a_CFLAGS = -some -other -flags
11721 Here @file{foo-bar.o} and @file{foo-main.o} will all be
11722 compiled with @samp{-some -flags}, while @file{libfoo_a-foo.o} will
11723 be compiled using @samp{-some -other -flags}. Eventually, all
11724 three objects will be linked to form @file{foo}.
11726 This trick can also be achieved using Libtool convenience libraries,
11727 for instance @samp{noinst_LTLIBRARIES = libfoo.la} (@pxref{Libtool
11728 Convenience Libraries}).
11730 Another tempting idea to implement per-object flags is to override the
11731 compile rules @command{automake} would output for these files.
11732 Automake will not define a rule for a target you have defined, so you
11733 could think about defining the @samp{foo-foo.o: foo.c} rule yourself.
11734 We recommend against this, because this is error prone. For instance,
11735 if you add such a rule to the first example, it will break the day you
11736 decide to remove @code{foo_CFLAGS} (because @file{foo.c} will then be
11737 compiled as @file{foo.o} instead of @file{foo-foo.o}, @pxref{Renamed
11738 Objects}). Also in order to support dependency tracking, the two
11739 @file{.o}/@file{.obj} extensions, and all the other flags variables
11740 involved in a compilation, you will end up modifying a copy of the
11741 rule previously output by @command{automake} for this file. If a new
11742 release of Automake generates a different rule, your copy will need to
11743 be updated by hand.
11745 @node Multiple Outputs
11746 @section Handling Tools that Produce Many Outputs
11747 @cindex multiple outputs, rules with
11748 @cindex many outputs, rules with
11749 @cindex rules with multiple outputs
11751 This section describes a @command{make} idiom that can be used when a
11752 tool produces multiple output files. It is not specific to Automake
11753 and can be used in ordinary @file{Makefile}s.
11755 Suppose we have a program called @command{foo} that will read one file
11756 called @file{data.foo} and produce two files named @file{data.c} and
11757 @file{data.h}. We want to write a @file{Makefile} rule that captures
11758 this one-to-two dependency.
11760 The naive rule is incorrect:
11763 # This is incorrect.
11764 data.c data.h: data.foo
11769 What the above rule really says is that @file{data.c} and
11770 @file{data.h} each depend on @file{data.foo}, and can each be built by
11771 running @samp{foo data.foo}. In other words it is equivalent to:
11774 # We do not want this.
11782 which means that @command{foo} can be run twice. Usually it will not
11783 be run twice, because @command{make} implementations are smart enough
11784 to check for the existence of the second file after the first one has
11785 been built; they will therefore detect that it already exists.
11786 However there are a few situations where it can run twice anyway:
11790 The most worrying case is when running a parallel @command{make}. If
11791 @file{data.c} and @file{data.h} are built in parallel, two @samp{foo
11792 data.foo} commands will run concurrently. This is harmful.
11794 Another case is when the dependency (here @file{data.foo}) is
11795 (or depends upon) a phony target.
11798 A solution that works with parallel @command{make} but not with
11799 phony dependencies is the following:
11802 data.c data.h: data.foo
11808 The above rules are equivalent to
11813 data.h: data.foo data.c
11818 therefore a parallel @command{make} will have to serialize the builds
11819 of @file{data.c} and @file{data.h}, and will detect that the second is
11820 no longer needed once the first is over.
11822 Using this pattern is probably enough for most cases. However it does
11823 not scale easily to more output files (in this scheme all output files
11824 must be totally ordered by the dependency relation), so we will
11825 explore a more complicated solution.
11827 Another idea is to write the following:
11830 # There is still a problem with this one.
11837 The idea is that @samp{foo data.foo} is run only when @file{data.c}
11838 needs to be updated, but we further state that @file{data.h} depends
11839 upon @file{data.c}. That way, if @file{data.h} is required and
11840 @file{data.foo} is out of date, the dependency on @file{data.c} will
11843 This is almost perfect, but suppose we have built @file{data.h} and
11844 @file{data.c}, and then we erase @file{data.h}. Then, running
11845 @samp{make data.h} will not rebuild @file{data.h}. The above rules
11846 just state that @file{data.c} must be up-to-date with respect to
11847 @file{data.foo}, and this is already the case.
11849 What we need is a rule that forces a rebuild when @file{data.h} is
11850 missing. Here it is:
11856 ## Recover from the removal of $@@
11857 @@if test -f $@@; then :; else \
11859 $(MAKE) $(AM_MAKEFLAGS) data.c; \
11863 The above scheme can be extended to handle more outputs and more
11864 inputs. One of the outputs is selected to serve as a witness to the
11865 successful completion of the command, it depends upon all inputs, and
11866 all other outputs depend upon it. For instance, if @command{foo}
11867 should additionally read @file{data.bar} and also produce
11868 @file{data.w} and @file{data.x}, we would write:
11871 data.c: data.foo data.bar
11872 foo data.foo data.bar
11873 data.h data.w data.x: data.c
11874 ## Recover from the removal of $@@
11875 @@if test -f $@@; then :; else \
11877 $(MAKE) $(AM_MAKEFLAGS) data.c; \
11881 However there are now three minor problems in this setup. One is related
11882 to the timestamp ordering of @file{data.h}, @file{data.w},
11883 @file{data.x}, and @file{data.c}. Another one is a race condition
11884 if a parallel @command{make} attempts to run multiple instances of the
11885 recover block at once. Finally, the recursive rule breaks @samp{make -n}
11886 when run with GNU @command{make} (as well as some other @command{make}
11887 implementations), as it may remove @file{data.h} even when it should not
11888 (@pxref{MAKE Variable, , How the @code{MAKE} Variable Works, make,
11889 The GNU Make Manual}).
11891 Let us deal with the first problem. @command{foo} outputs four files,
11892 but we do not know in which order these files are created. Suppose
11893 that @file{data.h} is created before @file{data.c}. Then we have a
11894 weird situation. The next time @command{make} is run, @file{data.h}
11895 will appear older than @file{data.c}, the second rule will be
11896 triggered, a shell will be started to execute the @samp{if@dots{}fi}
11897 command, but actually it will just execute the @code{then} branch,
11898 that is: nothing. In other words, because the witness we selected is
11899 not the first file created by @command{foo}, @command{make} will start
11900 a shell to do nothing each time it is run.
11902 A simple riposte is to fix the timestamps when this happens.
11905 data.c: data.foo data.bar
11906 foo data.foo data.bar
11907 data.h data.w data.x: data.c
11908 @@if test -f $@@; then \
11911 ## Recover from the removal of $@@
11913 $(MAKE) $(AM_MAKEFLAGS) data.c; \
11917 Another solution is to use a different and dedicated file as witness,
11918 rather than using any of @command{foo}'s outputs.
11921 data.stamp: data.foo data.bar
11924 foo data.foo data.bar
11925 @@mv -f data.tmp $@@
11926 data.c data.h data.w data.x: data.stamp
11927 ## Recover from the removal of $@@
11928 @@if test -f $@@; then :; else \
11929 rm -f data.stamp; \
11930 $(MAKE) $(AM_MAKEFLAGS) data.stamp; \
11934 @file{data.tmp} is created before @command{foo} is run, so it has a
11935 timestamp older than output files output by @command{foo}. It is then
11936 renamed to @file{data.stamp} after @command{foo} has run, because we
11937 do not want to update @file{data.stamp} if @command{foo} fails.
11939 This solution still suffers from the second problem: the race
11940 condition in the recover rule. If, after a successful build, a user
11941 erases @file{data.c} and @file{data.h}, and runs @samp{make -j}, then
11942 @command{make} may start both recover rules in parallel. If the two
11943 instances of the rule execute @samp{$(MAKE) $(AM_MAKEFLAGS)
11944 data.stamp} concurrently the build is likely to fail (for instance, the
11945 two rules will create @file{data.tmp}, but only one can rename it).
11947 Admittedly, such a weird situation does not arise during ordinary
11948 builds. It occurs only when the build tree is mutilated. Here
11949 @file{data.c} and @file{data.h} have been explicitly removed without
11950 also removing @file{data.stamp} and the other output files.
11951 @code{make clean; make} will always recover from these situations even
11952 with parallel makes, so you may decide that the recover rule is solely
11953 to help non-parallel make users and leave things as-is. Fixing this
11954 requires some locking mechanism to ensure only one instance of the
11955 recover rule rebuilds @file{data.stamp}. One could imagine something
11956 along the following lines.
11959 data.c data.h data.w data.x: data.stamp
11960 ## Recover from the removal of $@@
11961 @@if test -f $@@; then :; else \
11962 trap 'rm -rf data.lock data.stamp' 1 2 13 15; \
11963 ## mkdir is a portable test-and-set
11964 if mkdir data.lock 2>/dev/null; then \
11965 ## This code is being executed by the first process.
11966 rm -f data.stamp; \
11967 $(MAKE) $(AM_MAKEFLAGS) data.stamp; \
11968 result=$$?; rm -rf data.lock; exit $$result; \
11970 ## This code is being executed by the follower processes.
11971 ## Wait until the first process is done.
11972 while test -d data.lock; do sleep 1; done; \
11973 ## Succeed if and only if the first process succeeded.
11974 test -f data.stamp; \
11979 Using a dedicated witness, like @file{data.stamp}, is very handy when
11980 the list of output files is not known beforehand. As an illustration,
11981 consider the following rules to compile many @file{*.el} files into
11982 @file{*.elc} files in a single command. It does not matter how
11983 @code{ELFILES} is defined (as long as it is not empty: empty targets
11984 are not accepted by POSIX).
11987 ELFILES = one.el two.el three.el @dots{}
11988 ELCFILES = $(ELFILES:=c)
11990 elc-stamp: $(ELFILES)
11993 $(elisp_comp) $(ELFILES)
11994 @@mv -f elc-temp $@@
11996 $(ELCFILES): elc-stamp
11997 @@if test -f $@@; then :; else \
11998 ## Recover from the removal of $@@
11999 trap 'rm -rf elc-lock elc-stamp' 1 2 13 15; \
12000 if mkdir elc-lock 2>/dev/null; then \
12001 ## This code is being executed by the first process.
12003 $(MAKE) $(AM_MAKEFLAGS) elc-stamp; \
12006 ## This code is being executed by the follower processes.
12007 ## Wait until the first process is done.
12008 while test -d elc-lock; do sleep 1; done; \
12009 ## Succeed if and only if the first process succeeded.
12010 test -f elc-stamp; exit $$?; \
12016 These solutions all still suffer from the third problem, namely that
12017 they break the promise that @samp{make -n} should not cause any actual
12018 changes to the tree. For those solutions that do not create lock files,
12019 it is possible to split the recover rules into two separate recipe
12020 commands, one of which does all work but the recursion, and the
12021 other invokes the recursive @samp{$(MAKE)}. The solutions involving
12022 locking could act upon the contents of the @samp{MAKEFLAGS} variable,
12023 but parsing that portably is not easy (@pxref{The Make Macro MAKEFLAGS,,,
12024 autoconf, The Autoconf Manual}). Here is an example:
12027 ELFILES = one.el two.el three.el @dots{}
12028 ELCFILES = $(ELFILES:=c)
12030 elc-stamp: $(ELFILES)
12033 $(elisp_comp) $(ELFILES)
12034 @@mv -f elc-temp $@@
12036 $(ELCFILES): elc-stamp
12037 ## Recover from the removal of $@@
12038 @@dry=; for f in x $$MAKEFLAGS; do \
12044 if test -f $@@; then :; else \
12045 $$dry trap 'rm -rf elc-lock elc-stamp' 1 2 13 15; \
12046 if $$dry mkdir elc-lock 2>/dev/null; then \
12047 ## This code is being executed by the first process.
12048 $$dry rm -f elc-stamp; \
12049 $(MAKE) $(AM_MAKEFLAGS) elc-stamp; \
12050 $$dry rmdir elc-lock; \
12052 ## This code is being executed by the follower processes.
12053 ## Wait until the first process is done.
12054 while test -d elc-lock && test -z "$$dry"; do \
12058 ## Succeed if and only if the first process succeeded.
12059 $$dry test -f elc-stamp; exit $$?; \
12064 For completeness it should be noted that GNU @command{make} is able to
12065 express rules with multiple output files using pattern rules
12066 (@pxref{Pattern Examples, , Pattern Rule Examples, make, The GNU Make
12067 Manual}). We do not discuss pattern rules here because they are not
12068 portable, but they can be convenient in packages that assume GNU
12072 @node Hard-Coded Install Paths
12073 @section Installing to Hard-Coded Locations
12076 My package needs to install some configuration file. I tried to use
12077 the following rule, but @samp{make distcheck} fails. Why?
12081 install-data-local:
12082 $(INSTALL_DATA) $(srcdir)/afile $(DESTDIR)/etc/afile
12087 My package needs to populate the installation directory of another
12088 package at install-time. I can easily compute that installation
12089 directory in @file{configure}, but if I install files therein,
12090 @samp{make distcheck} fails. How else should I do?
12093 These two setups share their symptoms: @samp{make distcheck} fails
12094 because they are installing files to hard-coded paths. In the later
12095 case the path is not really hard-coded in the package, but we can
12096 consider it to be hard-coded in the system (or in whichever tool that
12097 supplies the path). As long as the path does not use any of the
12098 standard directory variables (@samp{$(prefix)}, @samp{$(bindir)},
12099 @samp{$(datadir)}, etc.), the effect will be the same:
12100 user-installations are impossible.
12102 As a (non-root) user who wants to install a package, you usually have no
12103 right to install anything in @file{/usr} or @file{/usr/local}. So you
12104 do something like @samp{./configure --prefix ~/usr} to install a
12105 package in your own @file{~/usr} tree.
12107 If a package attempts to install something to some hard-coded path
12108 (e.g., @file{/etc/afile}), regardless of this @option{--prefix} setting,
12109 then the installation will fail. @samp{make distcheck} performs such
12110 a @option{--prefix} installation, hence it will fail too.
12112 Now, there are some easy solutions.
12114 The above @code{install-data-local} example for installing
12115 @file{/etc/afile} would be better replaced by
12118 sysconf_DATA = afile
12122 by default @code{sysconfdir} will be @samp{$(prefix)/etc}, because
12123 this is what the GNU Standards require. When such a package is
12124 installed on an FHS compliant system, the installer will have to set
12125 @samp{--sysconfdir=/etc}. As the maintainer of the package you
12126 should not be concerned by such site policies: use the appropriate
12127 standard directory variable to install your files so that the installer
12128 can easily redefine these variables to match their site conventions.
12130 Installing files that should be used by another package is slightly
12131 more involved. Let's take an example and assume you want to install
12132 a shared library that is a Python extension module. If you ask Python
12133 where to install the library, it will answer something like this:
12136 % @kbd{python -c 'from distutils import sysconfig;
12137 print sysconfig.get_python_lib(1,0)'}
12138 /usr/lib/python2.5/site-packages
12141 If you indeed use this absolute path to install your shared library,
12142 non-root users will not be able to install the package, hence
12145 Let's do better. The @samp{sysconfig.get_python_lib()} function
12146 actually accepts a third argument that will replace Python's
12147 installation prefix.
12150 % @kbd{python -c 'from distutils import sysconfig;
12151 print sysconfig.get_python_lib(1,0,"$@{exec_prefix@}")'}
12152 $@{exec_prefix@}/lib/python2.5/site-packages
12155 You can also use this new path. If you do
12158 root users can install your package with the same @option{--prefix}
12159 as Python (you get the behavior of the previous attempt)
12162 non-root users can install your package too, they will have the
12163 extension module in a place that is not searched by Python but they
12164 can work around this using environment variables (and if you installed
12165 scripts that use this shared library, it's easy to tell Python were to
12166 look in the beginning of your script, so the script works in both
12170 The @code{AM_PATH_PYTHON} macro uses similar commands to define
12171 @samp{$(pythondir)} and @samp{$(pyexecdir)} (@pxref{Python}).
12173 Of course not all tools are as advanced as Python regarding that
12174 substitution of @var{prefix}. So another strategy is to figure the
12175 part of the installation directory that must be preserved. For
12176 instance, here is how @code{AM_PATH_LISPDIR} (@pxref{Emacs Lisp})
12177 computes @samp{$(lispdir)}:
12180 $EMACS -batch -q -eval '(while load-path
12181 (princ (concat (car load-path) "\n"))
12182 (setq load-path (cdr load-path)))' >conftest.out
12185 -e '/.*\/lib\/x*emacs\/site-lisp$/@{
12186 s,.*/lib/\(x*emacs/site-lisp\)$,$@{libdir@}/\1,;p;q;
12188 -e '/.*\/share\/x*emacs\/site-lisp$/@{
12189 s,.*/share/\(x*emacs/site-lisp\),$@{datarootdir@}/\1,;p;q;
12194 I.e., it just picks the first directory that looks like
12195 @file{*/lib/*emacs/site-lisp} or @file{*/share/*emacs/site-lisp} in
12196 the search path of emacs, and then substitutes @samp{$@{libdir@}} or
12197 @samp{$@{datadir@}} appropriately.
12199 The emacs case looks complicated because it processes a list and
12200 expects two possible layouts, otherwise it's easy, and the benefits for
12201 non-root users are really worth the extra @command{sed} invocation.
12204 @node Debugging Make Rules
12205 @section Debugging Make Rules
12206 @cindex debugging rules
12207 @cindex rules, debugging
12209 The rules and dependency trees generated by @command{automake} can get
12210 rather complex, and leave the developer head-scratching when things
12211 don't work as expected. Besides the debug options provided by the
12212 @command{make} command (@pxref{Options Summary,,, make, The GNU Make
12213 Manual}), here's a couple of further hints for debugging makefiles
12214 generated by @command{automake} effectively:
12218 If less verbose output has been enabled in the package with the
12219 @samp{silent-rules} option (@pxref{Options}), you can use
12220 @code{make V=1} to see the commands being executed.
12222 @code{make -n} can help show what would be done without actually doing
12223 it. Note however, that this will @emph{still execute} commands prefixed
12224 with @samp{+}, and, when using GNU @command{make}, commands that contain
12225 the strings @samp{$(MAKE)} or @samp{$@{MAKE@}} (@pxref{Instead of
12226 Execution,,, make, The GNU Make Manual}).
12227 Typically, this is helpful to show what recursive rules would do, but it
12228 means that, in your own rules, you should not mix such recursion with
12229 actions that change any files.@footnote{Automake's @samp{dist} and
12230 @samp{distcheck} rules had a bug in this regard in that they created
12231 directories even with @option{-n}, but this has been fixed in Automake
12232 1.11.} Furthermore, note that GNU @command{make} will update
12233 prerequisites for the @file{Makefile} file itself even with @option{-n}
12234 (@pxref{Remaking Makefiles,,, make, The GNU Make Manual}).
12236 @code{make SHELL="/bin/bash -vx"} can help debug complex rules.
12237 @xref{The Make Macro SHELL,,, autoconf, The Autoconf Manual}, for some
12238 portability quirks associated with this construct.
12240 @code{echo 'print: ; @@echo "$(VAR)"' | make -f Makefile -f - print}
12241 can be handy to examine the expanded value of variables. You may need
12242 to use a target other than @samp{print} if that is already used or a
12243 file with that name exists.
12245 @url{http://bashdb.sourceforge.net/@/remake/} provides a modified
12246 GNU @command{make} command called @command{remake} that copes with
12247 complex GNU @command{make}-specific Makefiles and allows to trace
12248 execution, examine variables, and call rules interactively, much like
12253 @node Reporting Bugs
12254 @section Reporting Bugs
12256 Most nontrivial software has bugs. Automake is no exception. Although
12257 we cannot promise we can or will fix a bug, and we might not even agree
12258 that it is a bug, we want to hear about problems you encounter. Often we
12259 agree they are bugs and want to fix them.
12261 To make it possible for us to fix a bug, please report it. In order to
12262 do so effectively, it helps to know when and how to do it.
12264 Before reporting a bug, it is a good idea to see if it is already known.
12265 You can look at the @uref{http://debbugs.gnu.org/, GNU Bug Tracker}
12266 and the @uref{http://lists.gnu.org/@/archive/@/html/@/bug-automake/,
12267 bug-automake mailing list archives} for previous bug reports. We
12269 @uref{http://sourceware.org/@/cgi-bin/@/gnatsweb.pl?database=automake,
12270 Gnats database} for bug tracking, so some bugs might have been reported
12271 there already. Please do not use it for new bug reports, however.
12273 If the bug is not already known, it should be reported. It is very
12274 important to report bugs in a way that is useful and efficient. For
12275 this, please familiarize yourself with
12276 @uref{http://www.chiark.greenend.org.uk/@/~sgtatham/@/bugs.html, How to
12277 Report Bugs Effectively} and
12278 @uref{http://catb.org/@/~esr/@/faqs/@/smart-questions.html, How to Ask
12279 Questions the Smart Way}. This helps you and developers to save time
12280 which can then be spent on fixing more bugs and implementing more
12283 For a bug report, a feature request or other suggestions, please send
12284 email to @email{@value{PACKAGE_BUGREPORT}}. This will then open a new
12285 bug in the @uref{http://debbugs.gnu.org/@/automake, bug tracker}. Be
12286 sure to include the versions of Autoconf and Automake that you use.
12287 Ideally, post a minimal @file{Makefile.am} and @file{configure.ac} that
12288 reproduces the problem you encounter. If you have encountered test
12289 suite failures, please attach the @file{tests/test-suite.log} file.
12293 @chapter History of Automake
12295 This chapter presents various aspects of the history of Automake. The
12296 exhausted reader can safely skip it; this will be more of interest to
12297 nostalgic people, or to those curious to learn about the evolution of
12301 * Timeline:: The Automake story.
12302 * Dependency Tracking Evolution:: Evolution of Automatic Dependency Tracking
12303 * Releases:: Statistics about Automake Releases
12310 @item 1994-09-19 First CVS commit.
12312 If we can trust the CVS repository, David J.@tie{}MacKenzie (djm) started
12313 working on Automake (or AutoMake, as it was spelt then) this Monday.
12315 The first version of the @command{automake} script looks as follows.
12324 if test ! -f $@{makefile@}.am; then
12325 echo "automake: $@{makefile@}.am: No such honkin' file"
12330 exec 4> $@{makefile@}.in
12335 From this you can already see that Automake will be about reading
12336 @file{*.am} file and producing @file{*.in} files. You cannot see
12337 anything else, but if you also know that David is the one who created
12338 Autoconf two years before you can guess the rest.
12340 Several commits follow, and by the end of the day Automake is
12341 reported to work for GNU fileutils and GNU m4.
12343 The modus operandi is the one that is still used today: variable
12344 assignments in @file{Makefile.am} files trigger injections of
12345 precanned @file{Makefile} fragments into the generated
12346 @file{Makefile.in}. The use of @file{Makefile} fragments was inspired
12347 by the 4.4BSD @command{make} and include files, however Automake aims
12348 to be portable and to conform to the GNU standards for @file{Makefile}
12349 variables and targets.
12351 At this point, the most recent release of Autoconf is version 1.11,
12352 and David is preparing to release Autoconf 2.0 in late October. As a
12353 matter of fact, he will barely touch Automake after September.
12355 @item 1994-11-05 David MacKenzie's last commit.
12357 At this point Automake is a 200 line portable shell script, plus 332
12358 lines of @file{Makefile} fragments. In the @file{README}, David
12359 states his ambivalence between ``portable shell'' and ``more
12360 appropriate language'':
12363 I wrote it keeping in mind the possibility of it becoming an Autoconf
12364 macro, so it would run at configure-time. That would slow
12365 configuration down a bit, but allow users to modify the Makefile.am
12366 without needing to fetch the AutoMake package. And, the Makefile.in
12367 files wouldn't need to be distributed. But all of AutoMake would. So
12368 I might reimplement AutoMake in Perl, m4, or some other more
12369 appropriate language.
12372 Automake is described as ``an experimental Makefile generator''.
12373 There is no documentation. Adventurous users are referred to the
12374 examples and patches needed to use Automake with GNU m4 1.3, fileutils
12375 3.9, time 1.6, and development versions of find and indent.
12377 These examples seem to have been lost. However at the time of writing
12378 (10 years later in September, 2004) the FSF still distributes a
12379 package that uses this version of Automake: check out GNU termutils
12382 @item 1995-11-12 Tom Tromey's first commit.
12384 After one year of inactivity, Tom Tromey takes over the package.
12385 Tom was working on GNU cpio back then, and doing this just for fun,
12386 having trouble finding a project to contribute to. So while hacking
12387 he wanted to bring the @file{Makefile.in} up to GNU standards. This
12388 was hard, and one day he saw Automake on @url{ftp://alpha.gnu.org/},
12389 grabbed it and tried it out.
12391 Tom didn't talk to djm about it until later, just to make sure he
12392 didn't mind if he made a release. He did a bunch of early releases to
12395 Gnits was (and still is) totally informal, just a few GNU friends who
12396 Fran@,cois Pinard knew, who were all interested in making a common
12397 infrastructure for GNU projects, and shared a similar outlook on how
12398 to do it. So they were able to make some progress. It came along
12399 with Autoconf and extensions thereof, and then Automake from David and
12400 Tom (who were both gnitsians). One of their ideas was to write a
12401 document paralleling the GNU standards, that was more strict in some
12402 ways and more detailed. They never finished the GNITS standards, but
12403 the ideas mostly made their way into Automake.
12405 @item 1995-11-23 Automake 0.20
12407 Besides introducing automatic dependency tracking (@pxref{Dependency
12408 Tracking Evolution}), this version also supplies a 9-page manual.
12410 At this time @command{aclocal} and @code{AM_INIT_AUTOMAKE} did not
12411 exist, so many things had to be done by hand. For instance, here is
12412 what a configure.in (this is the former name of the
12413 @file{configure.ac} we use today) must contain in order to use
12419 AC_DEFINE_UNQUOTED(PACKAGE, "$PACKAGE")
12420 AC_DEFINE_UNQUOTED(VERSION, "$VERSION")
12427 (Today all of the above is achieved by @code{AC_INIT} and
12428 @code{AM_INIT_AUTOMAKE}.)
12430 Here is how programs are specified in @file{Makefile.am}:
12434 hello_SOURCES = hello.c
12437 This looks pretty much like what we do today, except the
12438 @code{PROGRAMS} variable has no directory prefix specifying where
12439 @file{hello} should be installed: all programs are installed in
12440 @samp{$(bindir)}. @code{LIBPROGRAMS} can be used to specify programs
12441 that must be built but not installed (it is called
12442 @code{noinst_PROGRAMS} nowadays).
12444 Programs can be built conditionally using @code{AC_SUBST}itutions:
12447 PROGRAMS = @@progs@@
12448 AM_PROGRAMS = foo bar baz
12451 (@code{AM_PROGRAMS} has since then been renamed to
12452 @code{EXTRA_PROGRAMS}.)
12454 Similarly scripts, static libraries, and data can be built and installed
12455 using the @code{LIBRARIES}, @code{SCRIPTS}, and @code{DATA} variables.
12456 However @code{LIBRARIES} were treated a bit specially in that Automake
12457 did automatically supply the @file{lib} and @file{.a} prefixes.
12458 Therefore to build @file{libcpio.a}, one had to write
12465 Extra files to distribute must be listed in @code{DIST_OTHER} (the
12466 ancestor of @code{EXTRA_DIST}). Also extra directories that are to be
12467 distributed should appear in @code{DIST_SUBDIRS}, but the manual
12468 describes this as a temporary ugly hack (today extra directories should
12469 also be listed in @code{EXTRA_DIST}, and @code{DIST_SUBDIRS} is used
12470 for another purpose, @pxref{Conditional Subdirectories}).
12472 @item 1995-11-26 Automake 0.21
12474 In less time than it takes to cook a frozen pizza, Tom rewrites
12475 Automake using Perl. At this time Perl 5 is only one year old, and
12476 Perl 4.036 is in use at many sites. Supporting several Perl versions
12477 has been a source of problems through the whole history of Automake.
12479 If you never used Perl 4, imagine Perl 5 without objects, without
12480 @samp{my} variables (only dynamically scoped @samp{local} variables),
12481 without function prototypes, with function calls that needs to be
12482 prefixed with @samp{&}, etc. Traces of this old style can still be
12483 found in today's @command{automake}.
12485 @item 1995-11-28 Automake 0.22
12486 @itemx 1995-11-29 Automake 0.23
12490 @item 1995-12-08 Automake 0.24
12491 @itemx 1995-12-10 Automake 0.25
12493 Releases are raining. 0.24 introduces the uniform naming scheme we
12494 use today, i.e., @code{bin_PROGRAMS} instead of @code{PROGRAMS},
12495 @code{noinst_LIBRARIES} instead of @code{LIBLIBRARIES}, etc. (However
12496 @code{EXTRA_PROGRAMS} does not exist yet, @code{AM_PROGRAMS} is still
12497 in use; and @code{TEXINFOS} and @code{MANS} still have no directory
12498 prefixes.) Adding support for prefixes like that was one of the major
12499 ideas in @command{automake}; it has lasted pretty well.
12501 AutoMake is renamed to Automake (Tom seems to recall it was Fran@,cois
12504 0.25 fixes a Perl 4 portability bug.
12506 @item 1995-12-18 Jim Meyering starts using Automake in GNU Textutils.
12507 @item 1995-12-31 Fran@,cois Pinard starts using Automake in GNU tar.
12509 @item 1996-01-03 Automake 0.26
12510 @itemx 1996-01-03 Automake 0.27
12512 Of the many changes and suggestions sent by Fran@,cois Pinard and
12513 included in 0.26, perhaps the most important is the advice that to
12514 ease customization a user rule or variable definition should always
12515 override an Automake rule or definition.
12517 Gordon Matzigkeit and Jim Meyering are two other early contributors
12518 that have been sending fixes.
12520 0.27 fixes yet another Perl 4 portability bug.
12522 @item 1996-01-13 Automake 0.28
12524 Automake starts scanning @file{configure.in} for @code{LIBOBJS}
12525 support. This is an important step because until this version
12526 Automake only knew about the @file{Makefile.am}s it processed.
12527 @file{configure.in} was Autoconf's world and the link between Autoconf
12528 and Automake had to be done by the @file{Makefile.am} author. For
12529 instance, if @file{config.h} was generated by @file{configure}, it was the
12530 package maintainer's responsibility to define the @code{CONFIG_HEADER}
12531 variable in each @file{Makefile.am}.
12533 Succeeding releases will rely more and more on scanning
12534 @file{configure.in} to better automate the Autoconf integration.
12536 0.28 also introduces the @code{AUTOMAKE_OPTIONS} variable and the
12537 @option{--gnu} and @option{--gnits} options, the latter being stricter.
12539 @item 1996-02-07 Automake 0.29
12541 Thanks to @file{configure.in} scanning, @code{CONFIG_HEADER} is gone,
12542 and rebuild rules for @file{configure}-generated file are
12543 automatically output.
12545 @code{TEXINFOS} and @code{MANS} converted to the uniform naming
12548 @item 1996-02-24 Automake 0.30
12550 The test suite is born. It contains 9 tests. From now on test cases
12551 will be added pretty regularly (@pxref{Releases}), and this proved to
12552 be really helpful later on.
12554 @code{EXTRA_PROGRAMS} finally replaces @code{AM_PROGRAMS}.
12556 All the third-party Autoconf macros, written mostly by Fran@,cois
12557 Pinard (and later Jim Meyering), are distributed in Automake's
12558 hand-written @file{aclocal.m4} file. Package maintainers are expected
12559 to extract the necessary macros from this file. (In previous versions
12560 you had to copy and paste them from the manual...)
12562 @item 1996-03-11 Automake 0.31
12564 The test suite in 0.30 was run via a long @code{check-local} rule. Upon
12565 Ulrich Drepper's suggestion, 0.31 makes it an Automake rule output
12566 whenever the @code{TESTS} variable is defined.
12568 @code{DIST_OTHER} is renamed to @code{EXTRA_DIST}, and the @code{check_}
12569 prefix is introduced. The syntax is now the same as today.
12571 @item 1996-03-15 Gordon Matzigkeit starts writing libtool.
12573 @item 1996-04-27 Automake 0.32
12575 @code{-hook} targets are introduced; an idea from Dieter Baron.
12577 @file{*.info} files, which were output in the build directory are
12578 now built in the source directory, because they are distributed. It
12579 seems these files like to move back and forth as that will happen
12580 again in future versions.
12582 @item 1996-05-18 Automake 0.33
12584 Gord Matzigkeit's main two contributions:
12587 @item very preliminary libtool support
12588 @item the distcheck rule
12591 Although they were very basic at this point, these are probably
12592 among the top features for Automake today.
12594 Jim Meyering also provides the infamous @code{jm_MAINTAINER_MODE},
12595 since then renamed to @code{AM_MAINTAINER_MODE} and abandoned by its
12596 author (@pxref{maintainer-mode}).
12598 @item 1996-05-28 Automake 1.0
12600 After only six months of heavy development, the @command{automake} script is
12601 3134 lines long, plus 973 lines of @file{Makefile} fragments. The
12602 package has 30 pages of documentation, and 38 test cases.
12603 @file{aclocal.m4} contains 4 macros.
12605 From now on and until version 1.4, new releases will occur at a rate
12606 of about one a year. 1.1 did not exist, actually 1.1b to 1.1p have
12607 been the name of beta releases for 1.2. This is the first time
12608 Automake uses suffix letters to designate beta releases, a habit that
12611 @item 1996-10-10 Kevin Dalley packages Automake 1.0 for Debian GNU/Linux.
12613 @item 1996-11-26 David J.@tie{}MacKenzie releases Autoconf 2.12.
12615 Between June and October, the Autoconf development is almost stalled.
12616 Roland McGrath has been working at the beginning of the year. David
12617 comes back in November to release 2.12, but he won't touch Autoconf
12618 anymore after this year, and Autoconf then really stagnates. The
12619 desolate Autoconf @file{ChangeLog} for 1997 lists only 7 commits.
12621 @item 1997-02-28 @email{automake@@gnu.ai.mit.edu} list alive
12623 The mailing list is announced as follows:
12625 I've created the "automake" mailing list. It is
12626 "automake@@gnu.ai.mit.edu". Administrivia, as always, to
12627 automake-request@@gnu.ai.mit.edu.
12629 The charter of this list is discussion of automake, autoconf, and
12630 other configuration/portability tools (e.g., libtool). It is expected
12631 that discussion will range from pleas for help all the way up to
12634 This list is archived on the FSF machines. Offhand I don't know if
12635 you can get the archive without an account there.
12637 This list is open to anybody who wants to join. Tell all your
12642 Before that people were discussing Automake privately, on the Gnits
12643 mailing list (which is not public either), and less frequently on
12644 @code{gnu.misc.discuss}.
12646 @code{gnu.ai.mit.edu} is now @code{gnu.org}, in case you never
12647 noticed. The archives of the early years of the
12648 @code{automake@@gnu.org} list have been lost, so today it is almost
12649 impossible to find traces of discussions that occurred before 1999.
12650 This has been annoying more than once, as such discussions can be
12651 useful to understand the rationale behind a piece of uncommented code
12652 that was introduced back then.
12654 @item 1997-06-22 Automake 1.2
12656 Automake developments continues, and more and more new Autoconf macros
12657 are required. Distributing them in @file{aclocal.m4} and requiring
12658 people to browse this file to extract the relevant macros becomes
12659 uncomfortable. Ideally, some of them should be contributed to
12660 Autoconf so that they can be used directly, however Autoconf is
12661 currently inactive. Automake 1.2 consequently introduces
12662 @command{aclocal} (@command{aclocal} was actually started on
12663 1996-07-28), a tool that automatically constructs an @file{aclocal.m4}
12664 file from a repository of third-party macros. Because Autoconf has
12665 stalled, Automake also becomes a kind of repository for such
12666 third-party macros, even macros completely unrelated to Automake (for
12667 instance macros that fix broken Autoconf macros).
12669 The 1.2 release contains 20 macros, including the
12670 @code{AM_INIT_AUTOMAKE} macro that simplifies the creation of
12671 @file{configure.in}.
12673 Libtool is fully supported using @code{*_LTLIBRARIES}.
12675 The missing script is introduced by Fran@,cois Pinard; it is meant to be
12676 a better solution than @code{AM_MAINTAINER_MODE}
12677 (@pxref{maintainer-mode}).
12679 Conditionals support was implemented by Ian Lance Taylor. At the
12680 time, Tom and Ian were working on an internal project at Cygnus. They
12681 were using ILU, which is pretty similar to CORBA@. They wanted to
12682 integrate ILU into their build, which was all @file{configure}-based,
12683 and Ian thought that adding conditionals to @command{automake} was
12684 simpler than doing all the work in @file{configure} (which was the
12685 standard at the time). So this was actually funded by Cygnus.
12687 This very useful but tricky feature will take a lot of time to
12688 stabilize. (At the time this text is written, there are still
12689 primaries that have not been updated to support conditional
12690 definitions in Automake 1.9.)
12692 The @command{automake} script has almost doubled: 6089 lines of Perl,
12693 plus 1294 lines of @file{Makefile} fragments.
12695 @item 1997-07-08 Gordon Matzigkeit releases Libtool 1.0.
12697 @item 1998-04-05 Automake 1.3
12699 This is a small advance compared to 1.2.
12700 It adds support for assembly, and preliminary support for Java.
12702 Perl 5.004_04 is out, but fixes to support Perl 4 are still
12703 regularly submitted whenever Automake breaks it.
12705 @item 1998-09-06 @code{sourceware.cygnus.com} is on-line.
12707 Sourceware was setup by Jason Molenda to host open source projects.
12709 @item 1998-09-19 Automake CVS repository moved to @code{sourceware.cygnus.com}
12710 @itemx 1998-10-26 @code{sourceware.cygnus.com} announces it hosts Automake:
12711 Automake is now hosted on @code{sourceware.cygnus.com}. It has a
12712 publicly accessible CVS repository. This CVS repository is a copy of
12713 the one Tom was using on his machine, which in turn is based on
12714 a copy of the CVS repository of David MacKenzie. This is why we still
12715 have to full source history. (Automake was on Sourceware until 2007-10-29,
12716 when it moved to a git repository on @code{savannah.gnu.org},
12717 but the Sourceware host had been renamed to @code{sources.redhat.com}.)
12719 The oldest file in the administrative directory of the CVS repository
12720 that was created on Sourceware is dated 1998-09-19, while the
12721 announcement that @command{automake} and @command{autoconf} had joined
12722 @command{sourceware} was made on 1998-10-26. They were among the
12723 first projects to be hosted there.
12725 The heedful reader will have noticed Automake was exactly 4 years old
12728 @item 1999-01-05 Ben Elliston releases Autoconf 2.13.
12730 @item 1999-01-14 Automake 1.4
12732 This release adds support for Fortran 77 and for the @code{include}
12733 statement. Also, @samp{+=} assignments are introduced, but it is
12734 still quite easy to fool Automake when mixing this with conditionals.
12736 These two releases, Automake 1.4 and Autoconf 2.13 make a duo that
12737 will be used together for years.
12739 @command{automake} is 7228 lines, plus 1591 lines of Makefile
12740 fragment, 20 macros (some 1.3 macros were finally contributed back to
12741 Autoconf), 197 test cases, and 51 pages of documentation.
12743 @item 1999-03-27 The @code{user-dep-branch} is created on the CVS repository.
12745 This implements a new dependency tracking schemed that should be
12746 able to handle automatic dependency tracking using any compiler (not
12747 just gcc) and any make (not just GNU @command{make}). In addition,
12748 the new scheme should be more reliable than the old one, as
12749 dependencies are generated on the end user's machine. Alexandre Oliva
12750 creates depcomp for this purpose.
12752 @xref{Dependency Tracking Evolution}, for more details about the
12753 evolution of automatic dependency tracking in Automake.
12755 @item 1999-11-21 The @code{user-dep-branch} is merged into the main trunk.
12757 This was a huge problem since we also had patches going in on the
12758 trunk. The merge took a long time and was very painful.
12762 Since September 1999 and until 2003, Akim Demaille will be zealously
12763 revamping Autoconf.
12766 I think the next release should be called "3.0".@*
12767 Let's face it: you've basically rewritten autoconf.@*
12768 Every weekend there are 30 new patches.@*
12769 I don't see how we could call this "2.15" with a straight face.@*
12770 -- Tom Tromey on @email{autoconf@@gnu.org}
12773 Actually Akim works like a submarine: he will pile up patches while he
12774 works off-line during the weekend, and flush them in batch when he
12775 resurfaces on Monday.
12779 On this Wednesday, Autoconf 2.49c, the last beta before Autoconf 2.50
12780 is out, and Akim has to find something to do during his week-end :)
12784 Akim sends a batch of 14 patches to @email{automake@@gnu.org}.
12787 Aiieeee! I was dreading the day that the Demaillator turned his
12788 sights on automake@dots{} and now it has arrived! -- Tom Tromey
12791 It's only the beginning: in two months he will send 192 patches. Then
12792 he would slow down so Tom can catch up and review all this. Initially
12793 Tom actually read all these patches, then he probably trustingly
12794 answered OK to most of them, and finally gave up and let Akim apply
12795 whatever he wanted. There was no way to keep up with that patch rate.
12798 Anyway the patch below won't apply since it predates Akim's
12799 sourcequake; I have yet to figure where the relevant passage has
12800 been moved :) -- Alexandre Duret-Lutz
12803 All these patches were sent to and discussed on
12804 @email{automake@@gnu.org}, so subscribed users were literally drowning in
12805 technical mails. Eventually, the @email{automake-patches@@gnu.org}
12806 mailing list was created in May.
12808 Year after year, Automake had drifted away from its initial design:
12809 construct @file{Makefile.in} by assembling various @file{Makefile}
12810 fragments. In 1.4, lots of @file{Makefile} rules are being emitted at
12811 various places in the @command{automake} script itself; this does not
12812 help ensuring a consistent treatment of these rules (for instance
12813 making sure that user-defined rules override Automake's own rules).
12814 One of Akim's goal was moving all these hard-coded rules to separate
12815 @file{Makefile} fragments, so the logic could be centralized in a
12816 @file{Makefile} fragment processor.
12818 Another significant contribution of Akim is the interface with the
12819 ``trace'' feature of Autoconf. The way to scan @file{configure.in} at
12820 this time was to read the file and grep the various macro of interest
12821 to Automake. Doing so could break in many unexpected ways; @command{automake}
12822 could miss some definition (for instance @samp{AC_SUBST([$1], [$2])}
12823 where the arguments are known only when M4 is run), or conversely it
12824 could detect some macro that was not expanded (because it is called
12825 conditionally). In the CVS version of Autoconf, Akim had implemented
12826 the @option{--trace} option, which provides accurate information about
12827 where macros are actually called and with what arguments. Akim will
12828 equip Automake with a second @file{configure.in} scanner that uses
12829 this @option{--trace} interface. Since it was not sensible to drop the
12830 Autoconf 2.13 compatibility yet, this experimental scanner was only
12831 used when an environment variable was set, the traditional
12832 grep-scanner being still the default.
12834 @item 2001-04-25 Gary V.@tie{}Vaughan releases Libtool 1.4
12836 It has been more than two years since Automake 1.4, CVS Automake has
12837 suffered lot's of heavy changes and still is not ready for release.
12838 Libtool 1.4 had to be distributed with a patch against Automake 1.4.
12840 @item 2001-05-08 Automake 1.4-p1
12841 @itemx 2001-05-24 Automake 1.4-p2
12843 Gary V.@tie{}Vaughan, the principal Libtool maintainer, makes a ``patch
12844 release'' of Automake:
12847 The main purpose of this release is to have a stable automake
12848 which is compatible with the latest stable libtool.
12851 The release also contains obvious fixes for bugs in Automake 1.4,
12852 some of which were reported almost monthly.
12854 @item 2001-05-21 Akim Demaille releases Autoconf 2.50
12856 @item 2001-06-07 Automake 1.4-p3
12857 @itemx 2001-06-10 Automake 1.4-p4
12858 @itemx 2001-07-15 Automake 1.4-p5
12860 Gary continues his patch-release series. These also add support for
12861 some new Autoconf 2.50 idioms. Essentially, Autoconf now advocates
12862 @file{configure.ac} over @file{configure.in}, and it introduces a new
12863 syntax for @code{AC_OUTPUT}ing files.
12865 @item 2001-08-23 Automake 1.5
12867 A major and long-awaited release, that comes more than two years after
12868 1.4. It brings many changes, among which:
12870 @item The new dependency tracking scheme that uses @command{depcomp}.
12871 Aside from the improvement on the dependency tracking itself
12872 (@pxref{Dependency Tracking Evolution}), this also streamlines the use
12873 of @command{automake}-generated @file{Makefile.in}s as the @file{Makefile.in}s
12874 used during development are now the same as those used in
12875 distributions. Before that the @file{Makefile.in}s generated for
12876 maintainers required GNU @command{make} and GCC, they were different
12877 from the portable @file{Makefile} generated for distribution; this was
12878 causing some confusion.
12880 @item Support for per-target compilation flags.
12882 @item Support for reference to files in subdirectories in most
12883 @file{Makefile.am} variables.
12885 @item Introduction of the @code{dist_}, @code{nodist_}, and @code{nobase_}
12887 @item Perl 4 support is finally dropped.
12890 1.5 did break several packages that worked with 1.4. Enough so that
12891 Linux distributions could not easily install the new Automake version
12892 without breaking many of the packages for which they had to run
12893 @command{automake}.
12895 Some of these breakages were effectively bugs that would eventually be
12896 fixed in the next release. However, a lot of damage was caused by
12897 some changes made deliberately to render Automake stricter on some
12898 setup we did consider bogus. For instance, @samp{make distcheck} was
12899 improved to check that @samp{make uninstall} did remove all the files
12900 @samp{make install} installed, that @samp{make distclean} did not omit
12901 some file, and that a VPATH build would work even if the source
12902 directory was read-only. Similarly, Automake now rejects multiple
12903 definitions of the same variable (because that would mix very badly
12904 with conditionals), and @samp{+=} assignments with no previous
12905 definition. Because these changes all occurred suddenly after 1.4 had
12906 been established for more than two years, it hurt users.
12908 To make matter worse, meanwhile Autoconf (now at version 2.52) was
12909 facing similar troubles, for similar reasons.
12911 @item 2002-03-05 Automake 1.6
12913 This release introduced versioned installation (@pxref{API
12914 Versioning}). This was mainly pushed by Havoc Pennington, taking the
12915 GNOME source tree as motive: due to incompatibilities between the
12916 autotools it's impossible for the GNOME packages to switch to Autoconf
12917 2.53 and Automake 1.5 all at once, so they are currently stuck with
12918 Autoconf 2.13 and Automake 1.4.
12920 The idea was to call this version @file{automake-1.6}, call all its
12921 bug-fix versions identically, and switch to @file{automake-1.7} for
12922 the next release that adds new features or changes some rules. This
12923 scheme implies maintaining a bug-fix branch in addition to the
12924 development trunk, which means more work from the maintainer, but
12925 providing regular bug-fix releases proved to be really worthwhile.
12927 Like 1.5, 1.6 also introduced a bunch of incompatibilities, intentional or
12928 not. Perhaps the more annoying was the dependence on the newly
12929 released Autoconf 2.53. Autoconf seemed to have stabilized enough
12930 since its explosive 2.50 release and included changes required to fix
12931 some bugs in Automake. In order to upgrade to Automake 1.6, people
12932 now had to upgrade Autoconf too; for some packages it was no picnic.
12934 While versioned installation helped people to upgrade, it also
12935 unfortunately allowed people not to upgrade. At the time of writing,
12936 some Linux distributions are shipping packages for Automake 1.4, 1.5,
12937 1.6, 1.7, 1.8, and 1.9. Most of these still install 1.4 by default.
12938 Some distribution also call 1.4 the ``stable'' version, and present
12939 ``1.9'' as the development version; this does not really makes sense
12940 since 1.9 is way more solid than 1.4. All this does not help the
12943 @item 2002-04-11 Automake 1.6.1
12945 1.6, and the upcoming 1.4-p6 release were the last release by Tom.
12946 This one and those following will be handled by Alexandre
12947 Duret-Lutz. Tom is still around, and will be there until about 1.7,
12948 but his interest into Automake is drifting away towards projects like
12951 Alexandre has been using Automake since 2000, and started to
12952 contribute mostly on Akim's incitement (Akim and Alexandre have been
12953 working in the same room from 1999 to 2002). In 2001 and 2002 he had
12954 a lot of free time to enjoy hacking Automake.
12956 @item 2002-06-14 Automake 1.6.2
12958 @item 2002-07-28 Automake 1.6.3
12959 @itemx 2002-07-28 Automake 1.4-p6
12961 Two releases on the same day. 1.6.3 is a bug-fix release.
12963 Tom Tromey backported the versioned installation mechanism on the 1.4
12964 branch, so that Automake 1.6.x and Automake 1.4-p6 could be installed
12965 side by side. Another request from the GNOME folks.
12967 @item 2002-09-25 Automake 1.7
12969 This release switches to the new @file{configure.ac} scanner Akim
12970 was experimenting in 1.5.
12972 @item 2002-10-16 Automake 1.7.1
12973 @itemx 2002-12-06 Automake 1.7.2
12974 @itemx 2003-02-20 Automake 1.7.3
12975 @itemx 2003-04-23 Automake 1.7.4
12976 @itemx 2003-05-18 Automake 1.7.5
12977 @itemx 2003-07-10 Automake 1.7.6
12978 @itemx 2003-09-07 Automake 1.7.7
12979 @itemx 2003-10-07 Automake 1.7.8
12981 Many bug-fix releases. 1.7 lasted because the development version
12982 (upcoming 1.8) was suffering some major internal revamping.
12984 @item 2003-10-26 Automake on screen
12986 Episode 49, `Repercussions', in the third season of the `Alias' TV
12987 show is first aired.
12989 Marshall, one of the characters, is working on a computer virus that he
12990 has to modify before it gets into the wrong hands or something like
12991 that. The screenshots you see do not show any program code, they show
12992 a @file{Makefile.in} @code{generated by automake}...
12994 @item 2003-11-09 Automake 1.7.9
12996 @item 2003-12-10 Automake 1.8
12998 The most striking update is probably that of @command{aclocal}.
13000 @command{aclocal} now uses @code{m4_include} in the produced
13001 @file{aclocal.m4} when the included macros are already distributed
13002 with the package (an idiom used in many packages), which reduces code
13003 duplication. Many people liked that, but in fact this change was
13004 really introduced to fix a bug in rebuild rules: @file{Makefile.in}
13005 must be rebuilt whenever a dependency of @file{configure} changes, but
13006 all the @file{m4} files included in @file{aclocal.m4} where unknown
13007 from @command{automake}. Now @command{automake} can just trace the
13008 @code{m4_include}s to discover the dependencies.
13010 @command{aclocal} also starts using the @option{--trace} Autoconf option
13011 in order to discover used macros more accurately. This will turn out
13012 to be very tricky (later releases will improve this) as people had
13013 devised many ways to cope with the limitation of previous
13014 @command{aclocal} versions, notably using handwritten
13015 @code{m4_include}s: @command{aclocal} must make sure not to redefine a
13016 rule that is already included by such statement.
13018 Automake also has seen its guts rewritten. Although this rewriting
13019 took a lot of efforts, it is only apparent to the users in that some
13020 constructions previously disallowed by the implementation now work
13021 nicely. Conditionals, Locations, Variable and Rule definitions,
13022 Options: these items on which Automake works have been rewritten as
13023 separate Perl modules, and documented.
13025 @itemx 2004-01-11 Automake 1.8.1
13026 @itemx 2004-01-12 Automake 1.8.2
13027 @itemx 2004-03-07 Automake 1.8.3
13028 @itemx 2004-04-25 Automake 1.8.4
13029 @itemx 2004-05-16 Automake 1.8.5
13031 @item 2004-07-28 Automake 1.9
13033 This release tries to simplify the compilation rules it outputs to
13034 reduce the size of the Makefile. The complaint initially come from
13035 the libgcj developers. Their @file{Makefile.in} generated with
13036 Automake 1.4 and custom build rules (1.4 did not support compiled
13037 Java) is 250KB@. The one generated by 1.8 was over 9MB@! 1.9 gets it
13040 Aside from this it contains mainly minor changes and bug-fixes.
13042 @itemx 2004-08-11 Automake 1.9.1
13043 @itemx 2004-09-19 Automake 1.9.2
13045 Automake has ten years. This chapter of the manual was initially
13046 written for this occasion.
13048 @itemx 2007-10-29 Automake repository moves to @code{savannah.gnu.org} and uses
13049 git as primary repository.
13053 @node Dependency Tracking Evolution
13054 @section Dependency Tracking in Automake
13056 Over the years Automake has deployed three different dependency
13057 tracking methods. Each method, including the current one, has had
13058 flaws of various sorts. Here we lay out the different dependency
13059 tracking methods, their flaws, and their fixes. We conclude with
13060 recommendations for tool writers, and by indicating future directions
13061 for dependency tracking work in Automake.
13064 * First Take on Dependencies:: Precomputed dependency tracking
13065 * Dependencies As Side Effects:: Update at developer compile time
13066 * Dependencies for the User:: Update at user compile time
13067 * Techniques for Dependencies:: Alternative approaches
13068 * Recommendations for Tool Writers:: What tool writers can do to help
13069 * Future Directions for Dependencies:: Languages Automake does not know
13072 @node First Take on Dependencies
13073 @subsection First Take on Dependency Tracking
13074 @unnumberedsubsubsec Description
13076 Our first attempt at automatic dependency tracking was based on the
13077 method recommended by GNU @command{make}. (@pxref{Automatic
13078 Prerequisites, , Generating Prerequisites Automatically, make, The GNU
13081 This version worked by precomputing dependencies ahead of time. For
13082 each source file, it had a special @file{.P} file that held the
13083 dependencies. There was a rule to generate a @file{.P} file by
13084 invoking the compiler appropriately. All such @file{.P} files were
13085 included by the @file{Makefile}, thus implicitly becoming dependencies
13086 of @file{Makefile}.
13088 @unnumberedsubsubsec Bugs
13090 This approach had several critical bugs.
13094 The code to generate the @file{.P} file relied on @command{gcc}.
13095 (A limitation, not technically a bug.)
13097 The dependency tracking mechanism itself relied on GNU @command{make}.
13098 (A limitation, not technically a bug.)
13100 Because each @file{.P} file was a dependency of @file{Makefile}, this
13101 meant that dependency tracking was done eagerly by @command{make}.
13102 For instance, @samp{make clean} would cause all the dependency files
13103 to be updated, and then immediately removed. This eagerness also
13104 caused problems with some configurations; if a certain source file
13105 could not be compiled on a given architecture for some reason,
13106 dependency tracking would fail, aborting the entire build.
13108 As dependency tracking was done as a pre-pass, compile times were
13109 doubled--the compiler had to be run twice per source file.
13111 @samp{make dist} re-ran @command{automake} to generate a
13112 @file{Makefile} that did not have automatic dependency tracking (and
13113 that was thus portable to any version of @command{make}). In order to
13114 do this portably, Automake had to scan the dependency files and remove
13115 any reference that was to a source file not in the distribution.
13116 This process was error-prone. Also, if @samp{make dist} was run in an
13117 environment where some object file had a dependency on a source file
13118 that was only conditionally created, Automake would generate a
13119 @file{Makefile} that referred to a file that might not appear in the
13120 end user's build. A special, hacky mechanism was required to work
13124 @unnumberedsubsubsec Historical Note
13126 The code generated by Automake is often inspired by the
13127 @file{Makefile} style of a particular author. In the case of the first
13128 implementation of dependency tracking, I believe the impetus and
13129 inspiration was Jim Meyering. (I could be mistaken. If you know
13130 otherwise feel free to correct me.)
13132 @node Dependencies As Side Effects
13133 @subsection Dependencies As Side Effects
13134 @unnumberedsubsubsec Description
13136 The next refinement of Automake's automatic dependency tracking scheme
13137 was to implement dependencies as side effects of the compilation.
13138 This was aimed at solving the most commonly reported problems with the
13139 first approach. In particular we were most concerned with eliminating
13140 the weird rebuilding effect associated with make clean.
13142 In this approach, the @file{.P} files were included using the
13143 @code{-include} command, which let us create these files lazily. This
13144 avoided the @samp{make clean} problem.
13146 We only computed dependencies when a file was actually compiled. This
13147 avoided the performance penalty associated with scanning each file
13148 twice. It also let us avoid the other problems associated with the
13149 first, eager, implementation. For instance, dependencies would never
13150 be generated for a source file that was not compilable on a given
13151 architecture (because it in fact would never be compiled).
13153 @unnumberedsubsubsec Bugs
13157 This approach also relied on the existence of @command{gcc} and GNU
13158 @command{make}. (A limitation, not technically a bug.)
13160 Dependency tracking was still done by the developer, so the problems
13161 from the first implementation relating to massaging of dependencies by
13162 @samp{make dist} were still in effect.
13164 This implementation suffered from the ``deleted header file'' problem.
13165 Suppose a lazily-created @file{.P} file includes a dependency on a
13166 given header file, like this:
13169 maude.o: maude.c something.h
13172 Now suppose that you remove @file{something.h} and update @file{maude.c}
13173 so that this include is no longer needed. If you run @command{make},
13174 you will get an error because there is no way to create
13175 @file{something.h}.
13177 We fixed this problem in a later release by further massaging the
13178 output of @command{gcc} to include a dummy dependency for each header
13182 @node Dependencies for the User
13183 @subsection Dependencies for the User
13184 @unnumberedsubsubsec Description
13186 The bugs associated with @samp{make dist}, over time, became a real
13187 problem. Packages using Automake were being built on a large number
13188 of platforms, and were becoming increasingly complex. Broken
13189 dependencies were distributed in ``portable'' @file{Makefile.in}s,
13190 leading to user complaints. Also, the requirement for @command{gcc}
13191 and GNU @command{make} was a constant source of bug reports. The next
13192 implementation of dependency tracking aimed to remove these problems.
13194 We realized that the only truly reliable way to automatically track
13195 dependencies was to do it when the package itself was built. This
13196 meant discovering a method portable to any version of make and any
13197 compiler. Also, we wanted to preserve what we saw as the best point
13198 of the second implementation: dependency computation as a side effect
13201 In the end we found that most modern make implementations support some
13202 form of include directive. Also, we wrote a wrapper script that let
13203 us abstract away differences between dependency tracking methods for
13204 compilers. For instance, some compilers cannot generate dependencies
13205 as a side effect of compilation. In this case we simply have the
13206 script run the compiler twice. Currently our wrapper script
13207 (@command{depcomp}) knows about twelve different compilers (including
13208 a "compiler" that simply invokes @command{makedepend} and then the
13209 real compiler, which is assumed to be a standard Unix-like C compiler
13210 with no way to do dependency tracking).
13212 @unnumberedsubsubsec Bugs
13216 Running a wrapper script for each compilation slows down the build.
13218 Many users don't really care about precise dependencies.
13220 This implementation, like every other automatic dependency tracking
13221 scheme in common use today (indeed, every one we've ever heard of),
13222 suffers from the ``duplicated new header'' bug.
13224 This bug occurs because dependency tracking tools, such as the
13225 compiler, only generate dependencies on the successful opening of a
13226 file, and not on every probe.
13228 Suppose for instance that the compiler searches three directories for
13229 a given header, and that the header is found in the third directory.
13230 If the programmer erroneously adds a header file with the same name to
13231 the first directory, then a clean rebuild from scratch could fail
13232 (suppose the new header file is buggy), whereas an incremental rebuild
13235 What has happened here is that people have a misunderstanding of what
13236 a dependency is. Tool writers think a dependency encodes information
13237 about which files were read by the compiler. However, a dependency
13238 must actually encode information about what the compiler tried to do.
13240 This problem is not serious in practice. Programmers typically do not
13241 use the same name for a header file twice in a given project. (At
13242 least, not in C or C++. This problem may be more troublesome in
13243 Java.) This problem is easy to fix, by modifying dependency
13244 generators to record every probe, instead of every successful open.
13247 Since Automake generates dependencies as a side effect of compilation,
13248 there is a bootstrapping problem when header files are generated by
13249 running a program. The problem is that, the first time the build is
13250 done, there is no way by default to know that the headers are
13251 required, so make might try to run a compilation for which the headers
13252 have not yet been built.
13254 This was also a problem in the previous dependency tracking implementation.
13256 The current fix is to use @code{BUILT_SOURCES} to list built headers
13257 (@pxref{Sources}). This causes them to be built before any other
13258 build rules are run. This is unsatisfactory as a general solution,
13259 however in practice it seems sufficient for most actual programs.
13262 This code is used since Automake 1.5.
13264 In GCC 3.0, we managed to convince the maintainers to add special
13265 command-line options to help Automake more efficiently do its job. We
13266 hoped this would let us avoid the use of a wrapper script when
13267 Automake's automatic dependency tracking was used with @command{gcc}.
13269 Unfortunately, this code doesn't quite do what we want. In
13270 particular, it removes the dependency file if the compilation fails;
13271 we'd prefer that it instead only touch the file in any way if the
13272 compilation succeeds.
13274 Nevertheless, since Automake 1.7, when a recent @command{gcc} is
13275 detected at @command{configure} time, we inline the
13276 dependency-generation code and do not use the @command{depcomp}
13277 wrapper script. This makes compilations faster for those using this
13278 compiler (probably our primary user base). The counterpart is that
13279 because we have to encode two compilation rules in @file{Makefile}
13280 (with or without @command{depcomp}), the produced @file{Makefile}s are
13283 @node Techniques for Dependencies
13284 @subsection Techniques for Computing Dependencies
13286 There are actually several ways for a build tool like Automake to
13287 cause tools to generate dependencies.
13290 @item @command{makedepend}
13291 This was a commonly-used method in the past. The idea is to run a
13292 special program over the source and have it generate dependency
13293 information. Traditional implementations of @command{makedepend} are
13294 not completely precise; ordinarily they were conservative and
13295 discovered too many dependencies.
13297 An obvious way to generate dependencies is to simply write the tool so
13298 that it can generate the information needed by the build tool. This is
13299 also the most portable method. Many compilers have an option to
13300 generate dependencies. Unfortunately, not all tools provide such an
13302 @item The file system
13303 It is possible to write a special file system that tracks opens,
13304 reads, writes, etc, and then feed this information back to the build
13305 tool. @command{clearmake} does this. This is a very powerful
13306 technique, as it doesn't require cooperation from the
13307 tool. Unfortunately it is also very difficult to implement and also
13308 not practical in the general case.
13309 @item @code{LD_PRELOAD}
13310 Rather than use the file system, one could write a special library to
13311 intercept @code{open} and other syscalls. This technique is also quite
13312 powerful, but unfortunately it is not portable enough for use in
13313 @command{automake}.
13316 @node Recommendations for Tool Writers
13317 @subsection Recommendations for Tool Writers
13319 We think that every compilation tool ought to be able to generate
13320 dependencies as a side effect of compilation. Furthermore, at least
13321 while @command{make}-based tools are nearly universally in use (at
13322 least in the free software community), the tool itself should generate
13323 dummy dependencies for header files, to avoid the deleted header file
13324 bug. Finally, the tool should generate a dependency for each probe,
13325 instead of each successful file open, in order to avoid the duplicated
13328 @node Future Directions for Dependencies
13329 @subsection Future Directions for Dependencies
13331 Currently, only languages and compilers understood by Automake can
13332 have dependency tracking enabled. We would like to see if it is
13333 practical (and worthwhile) to let this support be extended by the user
13334 to languages unknown to Automake.
13337 @section Release Statistics
13339 The following table (inspired by @samp{perlhist(1)}) quantifies the
13340 evolution of Automake using these metrics:
13344 The date and version of the release.
13346 The number of lines of the @command{automake} script.
13348 The number of lines of the @command{aclocal} script.
13350 The number of lines of the @command{Perl} supporting modules.
13352 The number of lines of the @file{Makefile} fragments. The number in
13353 parentheses is the number of files.
13355 The number of lines (and files) of Autoconf macros.
13357 The number of pages of the documentation (the Postscript version).
13359 The number of test cases in the test suite. Of those, the number in
13360 parentheses is the number of generated test cases.
13363 @multitable {8888-88-88} {8.8-p8} {8888} {8888} {8888} {8888 (88)} {8888 (88)} {888} {888 (88)}
13364 @headitem Date @tab Rel @tab am @tab acl @tab pm @tab @file{*.am} @tab m4 @tab doc @tab t
13365 @item 1994-09-19 @tab CVS @tab 141 @tab @tab @tab 299 (24) @tab @tab @tab
13366 @item 1994-11-05 @tab CVS @tab 208 @tab @tab @tab 332 (28) @tab @tab @tab
13367 @item 1995-11-23 @tab 0.20 @tab 533 @tab @tab @tab 458 (35) @tab @tab 9 @tab
13368 @item 1995-11-26 @tab 0.21 @tab 613 @tab @tab @tab 480 (36) @tab @tab 11 @tab
13369 @item 1995-11-28 @tab 0.22 @tab 1116 @tab @tab @tab 539 (38) @tab @tab 12 @tab
13370 @item 1995-11-29 @tab 0.23 @tab 1240 @tab @tab @tab 541 (38) @tab @tab 12 @tab
13371 @item 1995-12-08 @tab 0.24 @tab 1462 @tab @tab @tab 504 (33) @tab @tab 14 @tab
13372 @item 1995-12-10 @tab 0.25 @tab 1513 @tab @tab @tab 511 (37) @tab @tab 15 @tab
13373 @item 1996-01-03 @tab 0.26 @tab 1706 @tab @tab @tab 438 (36) @tab @tab 16 @tab
13374 @item 1996-01-03 @tab 0.27 @tab 1706 @tab @tab @tab 438 (36) @tab @tab 16 @tab
13375 @item 1996-01-13 @tab 0.28 @tab 1964 @tab @tab @tab 934 (33) @tab @tab 16 @tab
13376 @item 1996-02-07 @tab 0.29 @tab 2299 @tab @tab @tab 936 (33) @tab @tab 17 @tab
13377 @item 1996-02-24 @tab 0.30 @tab 2544 @tab @tab @tab 919 (32) @tab 85 (1) @tab 20 @tab 9
13378 @item 1996-03-11 @tab 0.31 @tab 2877 @tab @tab @tab 919 (32) @tab 85 (1) @tab 29 @tab 17
13379 @item 1996-04-27 @tab 0.32 @tab 3058 @tab @tab @tab 921 (31) @tab 85 (1) @tab 30 @tab 26
13380 @item 1996-05-18 @tab 0.33 @tab 3110 @tab @tab @tab 926 (31) @tab 105 (1) @tab 30 @tab 35
13381 @item 1996-05-28 @tab 1.0 @tab 3134 @tab @tab @tab 973 (32) @tab 105 (1) @tab 30 @tab 38
13382 @item 1997-06-22 @tab 1.2 @tab 6089 @tab 385 @tab @tab 1294 (36) @tab 592 (20) @tab 37 @tab 126
13383 @item 1998-04-05 @tab 1.3 @tab 6415 @tab 422 @tab @tab 1470 (39) @tab 741 (23) @tab 39 @tab 156
13384 @item 1999-01-14 @tab 1.4 @tab 7240 @tab 426 @tab @tab 1591 (40) @tab 734 (20) @tab 51 @tab 197
13385 @item 2001-05-08 @tab 1.4-p1 @tab 7251 @tab 426 @tab @tab 1591 (40) @tab 734 (20) @tab 51 @tab 197
13386 @item 2001-05-24 @tab 1.4-p2 @tab 7268 @tab 439 @tab @tab 1591 (40) @tab 734 (20) @tab 49 @tab 197
13387 @item 2001-06-07 @tab 1.4-p3 @tab 7312 @tab 439 @tab @tab 1591 (40) @tab 734 (20) @tab 49 @tab 197
13388 @item 2001-06-10 @tab 1.4-p4 @tab 7321 @tab 439 @tab @tab 1591 (40) @tab 734 (20) @tab 49 @tab 198
13389 @item 2001-07-15 @tab 1.4-p5 @tab 7228 @tab 426 @tab @tab 1596 (40) @tab 734 (20) @tab 51 @tab 198
13390 @item 2001-08-23 @tab 1.5 @tab 8016 @tab 475 @tab 600 @tab 2654 (39) @tab 1166 (29) @tab 63 @tab 327
13391 @item 2002-03-05 @tab 1.6 @tab 8465 @tab 475 @tab 1136 @tab 2732 (39) @tab 1603 (27) @tab 66 @tab 365
13392 @item 2002-04-11 @tab 1.6.1 @tab 8544 @tab 475 @tab 1136 @tab 2741 (39) @tab 1603 (27) @tab 66 @tab 372
13393 @item 2002-06-14 @tab 1.6.2 @tab 8575 @tab 475 @tab 1136 @tab 2800 (39) @tab 1609 (27) @tab 67 @tab 386
13394 @item 2002-07-28 @tab 1.6.3 @tab 8600 @tab 475 @tab 1153 @tab 2809 (39) @tab 1609 (27) @tab 67 @tab 391
13395 @item 2002-07-28 @tab 1.4-p6 @tab 7332 @tab 455 @tab @tab 1596 (40) @tab 735 (20) @tab 49 @tab 197
13396 @item 2002-09-25 @tab 1.7 @tab 9189 @tab 471 @tab 1790 @tab 2965 (39) @tab 1606 (28) @tab 73 @tab 430
13397 @item 2002-10-16 @tab 1.7.1 @tab 9229 @tab 475 @tab 1790 @tab 2977 (39) @tab 1606 (28) @tab 73 @tab 437
13398 @item 2002-12-06 @tab 1.7.2 @tab 9334 @tab 475 @tab 1790 @tab 2988 (39) @tab 1606 (28) @tab 77 @tab 445
13399 @item 2003-02-20 @tab 1.7.3 @tab 9389 @tab 475 @tab 1790 @tab 3023 (39) @tab 1651 (29) @tab 84 @tab 448
13400 @item 2003-04-23 @tab 1.7.4 @tab 9429 @tab 475 @tab 1790 @tab 3031 (39) @tab 1644 (29) @tab 85 @tab 458
13401 @item 2003-05-18 @tab 1.7.5 @tab 9429 @tab 475 @tab 1790 @tab 3033 (39) @tab 1645 (29) @tab 85 @tab 459
13402 @item 2003-07-10 @tab 1.7.6 @tab 9442 @tab 475 @tab 1790 @tab 3033 (39) @tab 1660 (29) @tab 85 @tab 461
13403 @item 2003-09-07 @tab 1.7.7 @tab 9443 @tab 475 @tab 1790 @tab 3041 (39) @tab 1660 (29) @tab 90 @tab 467
13404 @item 2003-10-07 @tab 1.7.8 @tab 9444 @tab 475 @tab 1790 @tab 3041 (39) @tab 1660 (29) @tab 90 @tab 468
13405 @item 2003-11-09 @tab 1.7.9 @tab 9444 @tab 475 @tab 1790 @tab 3048 (39) @tab 1660 (29) @tab 90 @tab 468
13406 @item 2003-12-10 @tab 1.8 @tab 7171 @tab 585 @tab 7730 @tab 3236 (39) @tab 1666 (31) @tab 104 @tab 521
13407 @item 2004-01-11 @tab 1.8.1 @tab 7217 @tab 663 @tab 7726 @tab 3287 (39) @tab 1686 (31) @tab 104 @tab 525
13408 @item 2004-01-12 @tab 1.8.2 @tab 7217 @tab 663 @tab 7726 @tab 3288 (39) @tab 1686 (31) @tab 104 @tab 526
13409 @item 2004-03-07 @tab 1.8.3 @tab 7214 @tab 686 @tab 7735 @tab 3303 (39) @tab 1695 (31) @tab 111 @tab 530
13410 @item 2004-04-25 @tab 1.8.4 @tab 7214 @tab 686 @tab 7736 @tab 3310 (39) @tab 1701 (31) @tab 112 @tab 531
13411 @item 2004-05-16 @tab 1.8.5 @tab 7240 @tab 686 @tab 7736 @tab 3299 (39) @tab 1701 (31) @tab 112 @tab 533
13412 @item 2004-07-28 @tab 1.9 @tab 7508 @tab 715 @tab 7794 @tab 3352 (40) @tab 1812 (32) @tab 115 @tab 551
13413 @item 2004-08-11 @tab 1.9.1 @tab 7512 @tab 715 @tab 7794 @tab 3354 (40) @tab 1812 (32) @tab 115 @tab 552
13414 @item 2004-09-19 @tab 1.9.2 @tab 7512 @tab 715 @tab 7794 @tab 3354 (40) @tab 1812 (32) @tab 132 @tab 554
13415 @item 2004-11-01 @tab 1.9.3 @tab 7507 @tab 718 @tab 7804 @tab 3354 (40) @tab 1812 (32) @tab 134 @tab 556
13416 @item 2004-12-18 @tab 1.9.4 @tab 7508 @tab 718 @tab 7856 @tab 3361 (40) @tab 1811 (32) @tab 140 @tab 560
13417 @item 2005-02-13 @tab 1.9.5 @tab 7523 @tab 719 @tab 7859 @tab 3373 (40) @tab 1453 (32) @tab 142 @tab 562
13418 @item 2005-07-10 @tab 1.9.6 @tab 7539 @tab 699 @tab 7867 @tab 3400 (40) @tab 1453 (32) @tab 144 @tab 570
13419 @item 2006-10-15 @tab 1.10 @tab 7859 @tab 1072 @tab 8024 @tab 3512 (40) @tab 1496 (34) @tab 172 @tab 604
13420 @item 2008-01-19 @tab 1.10.1 @tab 7870 @tab 1089 @tab 8025 @tab 3520 (40) @tab 1499 (34) @tab 173 @tab 617
13421 @item 2008-11-23 @tab 1.10.2 @tab 7882 @tab 1089 @tab 8027 @tab 3540 (40) @tab 1509 (34) @tab 176 @tab 628
13422 @item 2009-05-17 @tab 1.11 @tab 8721 @tab 1092 @tab 8289 @tab 4164 (42) @tab 1714 (37) @tab 181 @tab 732 (20)
13426 @c ========================================================== Appendices
13429 @node Copying This Manual
13430 @appendix Copying This Manual
13433 * GNU Free Documentation License:: License for copying this manual
13436 @node GNU Free Documentation License
13437 @appendixsec GNU Free Documentation License
13445 * Macro Index:: Index of Autoconf macros
13446 * Variable Index:: Index of Makefile variables
13447 * General Index:: General index
13451 @appendixsec Macro Index
13455 @node Variable Index
13456 @appendixsec Variable Index
13460 @node General Index
13461 @appendixsec General Index
13468 @c LocalWords: texinfo setfilename settitle setchapternewpage texi direntry
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13471 @c LocalWords: dir Automake's ac Dist Gnits gnits cygnus dfn Autoconf's pxref
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13487 @c LocalWords: GWINSZ termios SRCDIR tarball bzip LISPDIR lispdir XEmacs CCAS
13488 @c LocalWords: emacsen MicroEmacs CCASFLAGS UX GCJ gcj GCJFLAGS posix DMALLOC
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13519 @c LocalWords: ARGS taggable ETAGSFLAGS lang ctags CTAGSFLAGS GTAGS gtags idl
13520 @c LocalWords: foocc doit idlC multilibs ABIs cmindex defmac ARG enableval FC
13521 @c LocalWords: MSG xtrue DBG pathchk CYGWIN afile proglink versioned CVS's TE
13522 @c LocalWords: wildcards Autoconfiscated subsubheading autotools Meyering API
13523 @c LocalWords: ois's wildcard Wportability cartouche vrindex printindex Duret
13524 @c LocalWords: DSOMEFLAG DVERSION automake Lutz insertcopying versioning FAQ
13525 @c LocalWords: LTLIBOBJ Libtool's libtool's libltdl dlopening itutions libbar
13526 @c LocalWords: WANTEDLIBS libhello sublibraries libtop libsub dlopened Ratfor
13527 @c LocalWords: mymodule timestamps timestamp underquoted MAKEINFOHTMLFLAGS te
13528 @c LocalWords: GNUmakefile Subpackages subpackage's subpackages aux
13529 @c LocalWords: detailmenu Timeline pwd reldir AUTOM autom PREREQ FOOBAR libc
13530 @c LocalWords: libhand subpackage moduleN libmain libmisc FCFLAGS FCCOMPILE
13531 @c LocalWords: FCLINK subst sed ELCFILES elc MAKEINFOHTML dvips esyscmd ustar
13532 @c LocalWords: tarballs Woverride vfi ELFILES djm AutoMake honkin FSF
13533 @c LocalWords: fileutils precanned MacKenzie's reimplement termutils Tromey's
13534 @c LocalWords: cois gnitsians LIBPROGRAMS progs LIBLIBRARIES Textutils Ulrich
13535 @c LocalWords: Matzigkeit Drepper's Gord Matzigkeit's jm Dalley Debian org
13536 @c LocalWords: Administrivia ILU CORBA Sourceware Molenda sourceware Elliston
13537 @c LocalWords: dep Oliva Akim Demaille Aiieeee Demaillator Akim's sourcequake
13538 @c LocalWords: grep backported screenshots libgcj KB unnumberedsubsubsec pre
13539 @c LocalWords: precomputing hacky makedepend inline clearmake LD PRELOAD Rel
13540 @c LocalWords: syscalls perlhist acl pm multitable headitem fdl appendixsec
13541 @c LocalWords: LTALLOCA MALLOC malloc memcmp strdup alloca libcompat xyz DFOO
13542 @c LocalWords: unprefixed buildable preprocessed DBAZ DDATADIR WARNINGCFLAGS
13543 @c LocalWords: LIBFOOCFLAGS LIBFOOLDFLAGS ftable testSubDir obj LIBTOOLFLAGS
13544 @c LocalWords: barexec Pinard's automatize initialize lzma xz