Installing the GNU C Library
****************************
-Before you do anything else, you should read the file `FAQ' located at
-the top level of the source tree. This file answers common questions
+Before you do anything else, you should read the FAQ at
+`http://sourceware.org/glibc/wiki/FAQ'. It answers common questions
and describes problems you may experience with compilation and
-installation. It is updated more frequently than this manual.
+installation.
- Features can be added to GNU Libc via "add-on" bundles. These are
-separate tar files, which you unpack into the top level of the source
-tree. Then you give `configure' the `--enable-add-ons' option to
-activate them, and they will be compiled into the library.
+Features can be added to the GNU C Library via "add-on" bundles. These
+are separate tar files, which you unpack into the top level of the
+source tree. Then you give `configure' the `--enable-add-ons' option
+to activate them, and they will be compiled into the library.
You will need recent versions of several GNU tools: definitely GCC
and GNU Make, and possibly others. *Note Tools for Compilation::,
below.
-Configuring and compiling GNU Libc
-==================================
+Configuring and compiling the GNU C Library
+===========================================
-GNU libc cannot be compiled in the source directory. You must build it
-in a separate build directory. For example, if you have unpacked the
-glibc sources in `/src/gnu/glibc-VERSION', create a directory
-`/src/gnu/glibc-build' to put the object files in. This allows
-removing the whole build directory in case an error occurs, which is
-the safest way to get a fresh start and should always be done.
+The GNU C Library cannot be compiled in the source directory. You must
+build it in a separate build directory. For example, if you have
+unpacked the GNU C Library sources in `/src/gnu/glibc-VERSION', create
+a directory `/src/gnu/glibc-build' to put the object files in. This
+allows removing the whole build directory in case an error occurs,
+which is the safest way to get a fresh start and should always be done.
From your object directory, run the shell script `configure' located
at the top level of the source tree. In the scenario above, you'd type
$ ../glibc-VERSION/configure ARGS...
Please note that even though you're building in a separate build
-directory, the compilation needs to modify a few files in the source
-directory, especially some files in the manual subdirectory.
+directory, the compilation may need to create or modify files and
+directories in the source directory.
`configure' takes many options, but the only one that is usually
mandatory is `--prefix'. This option tells `configure' where you want
-glibc installed. This defaults to `/usr/local', but the normal setting
-to install as the standard system library is `--prefix=/usr' for
-GNU/Linux systems and `--prefix=' (an empty prefix) for GNU/Hurd
-systems.
+the GNU C Library installed. This defaults to `/usr/local', but the
+normal setting to install as the standard system library is
+`--prefix=/usr' for GNU/Linux systems and `--prefix=' (an empty prefix)
+for GNU/Hurd systems.
It may also be useful to set the CC and CFLAGS variables in the
environment when running `configure'. CC selects the C compiler that
`--with-headers=DIRECTORY'
Look for kernel header files in DIRECTORY, not `/usr/include'.
- Glibc needs information from the kernel's header files describing
- the interface to the kernel. Glibc will normally look in
- `/usr/include' for them, but if you specify this option, it will
- look in DIRECTORY instead.
+ The GNU C Library needs information from the kernel's header files
+ describing the interface to the kernel. The GNU C Library will
+ normally look in `/usr/include' for them, but if you specify this
+ option, it will look in DIRECTORY instead.
This option is primarily of use on a system where the headers in
- `/usr/include' come from an older version of glibc. Conflicts can
- occasionally happen in this case. You can also use this option if
- you want to compile glibc with a newer set of kernel headers than
- the ones found in `/usr/include'.
+ `/usr/include' come from an older version of the GNU C Library.
+ Conflicts can occasionally happen in this case. You can also use
+ this option if you want to compile the GNU C Library with a newer
+ set of kernel headers than the ones found in `/usr/include'.
`--enable-add-ons[=LIST]'
Specify add-on packages to include in the build. If this option is
Use the binutils (assembler and linker) in `DIRECTORY', not the
ones the C compiler would default to. You can use this option if
the default binutils on your system cannot deal with all the
- constructs in the GNU C library. In that case, `configure' will
+ constructs in the GNU C Library. In that case, `configure' will
detect the problem and suppress these constructs, so that the
library will still be usable, but functionality may be lost--for
example, you can't build a shared libc with old binutils.
Don't build libraries with profiling information. You may want to
use this option if you don't plan to do profiling.
-`--disable-versioning'
- Don't compile the shared libraries with symbol version information.
- Doing this will make the resulting library incompatible with old
- binaries, so it's not recommended.
-
`--enable-static-nss'
Compile static versions of the NSS (Name Service Switch) libraries.
This is not recommended because it defeats the purpose of NSS; a
this can be prevented though there generally is no reason since it
creates compatibility problems.
+`--enable-hardcoded-path-in-tests'
+ By default, dynamic tests are linked to run with the installed C
+ library. This option hardcodes the newly built C library path in
+ dynamic tests so that they can be invoked directly.
+
+`--enable-lock-elision=yes'
+ Enable lock elision for pthread mutexes by default.
+
+`--enable-pt_chown'
+ The file `pt_chown' is a helper binary for `grantpt' (*note
+ Pseudo-Terminals: Allocation.) that is installed setuid root to
+ fix up pseudo-terminal ownership. It is not built by default
+ because systems using the Linux kernel are commonly built with the
+ `devpts' filesystem enabled and mounted at `/dev/pts', which
+ manages pseudo-terminal ownership automatically. By using
+ `--enable-pt_chown', you may build `pt_chown' and install it
+ setuid and owned by `root'. The use of `pt_chown' introduces
+ additional security risks to the system and you should enable it
+ only if you understand and accept those risks.
+
`--build=BUILD-SYSTEM'
`--host=HOST-SYSTEM'
These options are for cross-compiling. If you specify both
options and BUILD-SYSTEM is different from HOST-SYSTEM, `configure'
- will prepare to cross-compile glibc from BUILD-SYSTEM to be used
- on HOST-SYSTEM. You'll probably need the `--with-headers' option
- too, and you may have to override CONFIGURE's selection of the
- compiler and/or binutils.
+ will prepare to cross-compile the GNU C Library from BUILD-SYSTEM
+ to be used on HOST-SYSTEM. You'll probably need the
+ `--with-headers' option too, and you may have to override
+ CONFIGURE's selection of the compiler and/or binutils.
If you only specify `--host', `configure' will prepare for a
native compile but use what you specify instead of guessing what
- your system is. This is most useful to change the CPU submodel.
+ your system is. This is most useful to change the CPU submodel.
For example, if `configure' guesses your machine as
- `i586-pc-linux-gnu' but you want to compile a library for 386es,
- give `--host=i386-pc-linux-gnu' or just `--host=i386-linux' and add
- the appropriate compiler flags (`-mcpu=i386' will do the trick) to
+ `i686-pc-linux-gnu' but you want to compile a library for 586es,
+ give `--host=i586-pc-linux-gnu' or just `--host=i586-linux' and add
+ the appropriate compiler flags (`-mcpu=i586' will do the trick) to
CFLAGS.
If you specify just `--build', `configure' will get confused.
+`--with-pkgversion=VERSION'
+ Specify a description, possibly including a build number or build
+ date, of the binaries being built, to be included in `--version'
+ output from programs installed with the GNU C Library. For
+ example, `--with-pkgversion='FooBar GNU/Linux glibc build 123''.
+ The default value is `GNU libc'.
+
+`--with-bugurl=URL'
+ Specify the URL that users should visit if they wish to report a
+ bug, to be included in `--help' output from programs installed with
+ the GNU C Library. The default value refers to the main
+ bug-reporting information for the GNU C Library.
+
To build the library and related programs, type `make'. This will
produce a lot of output, some of which may look like errors from `make'
but isn't. Look for error messages from `make' containing `***'.
do not use the built library, and report a bug after verifying that the
problem is not already known. *Note Reporting Bugs::, for instructions
on reporting bugs. Note that some of the tests assume they are not
-being run by `root'. We recommend you compile and test glibc as an
-unprivileged user.
+being run by `root'. We recommend you compile and test the GNU C
+Library as an unprivileged user.
Before reporting bugs make sure there is no problem with your system.
The tests (and later installation) use some pre-existing files of the
system such as `/etc/passwd', `/etc/nsswitch.conf' and others. These
files must all contain correct and sensible content.
+ Normally, `make check' will run all the tests before reporting all
+problems found and exiting with error status if any problems occurred.
+You can specify `stop-on-test-failure=y' when running `make check' to
+make the test run stop and exit with an error status immediately when a
+failure occurs.
+
To format the `GNU C Library Reference Manual' for printing, type
`make dvi'. You need a working TeX installation to do this. The
-distribution already includes the on-line formatted version of the
-manual, as Info files. You can regenerate those with `make info', but
-it shouldn't be necessary.
+distribution builds the on-line formatted version of the manual, as
+Info files, as part of the build process. You can build them manually
+with `make info'.
The library has a number of special-purpose configuration parameters
which you can find in `Makeconfig'. These can be overwritten with the
file is included and parsed by `make' and has to follow the conventions
for makefiles.
- It is easy to configure the GNU C library for cross-compilation by
+ It is easy to configure the GNU C Library for cross-compilation by
setting a few variables in `configparms'. Set `CC' to the
cross-compiler for the target you configured the library for; it is
important to use this same `CC' value when running `configure', like
to use for programs run on the build system as part of compiling the
library. You may need to set `AR' to cross-compiling versions of `ar'
if the native tools are not configured to work with object files for
-the target you configured for.
+the target you configured for. When cross-compiling the GNU C Library,
+it may be tested using `make check
+test-wrapper="SRCDIR/scripts/cross-test-ssh.sh HOSTNAME"', where SRCDIR
+is the absolute directory name for the main source directory and
+HOSTNAME is the host name of a system that can run the newly built
+binaries of the GNU C Library. The source and build directories must
+be visible at the same locations on both the build system and HOSTNAME.
+
+ In general, when testing the GNU C Library, `test-wrapper' may be set
+to the name and arguments of any program to run newly built binaries.
+This program must preserve the arguments to the binary being run, its
+working directory and the standard input, output and error file
+descriptors. If `TEST-WRAPPER env' will not work to run a program with
+environment variables set, then `test-wrapper-env' must be set to a
+program that runs a newly built program with environment variable
+assignments in effect, those assignments being specified as `VAR=VALUE'
+before the name of the program to be run. If multiple assignments to
+the same variable are specified, the last assignment specified must
+take precedence.
Installing the C Library
========================
To install the library and its header files, and the Info files of the
-manual, type `env LANGUAGE=C LC_ALL=C make install'. This will build
-things, if necessary, before installing them; however, you should still
-compile everything first. If you are installing glibc as your primary
-C library, we recommend that you shut the system down to single-user
-mode first, and reboot afterward. This minimizes the risk of breaking
+manual, type `make install'. This will build things, if necessary,
+before installing them; however, you should still compile everything
+first. If you are installing the GNU C Library as your primary C
+library, we recommend that you shut the system down to single-user mode
+first, and reboot afterward. This minimizes the risk of breaking
things when the library changes out from underneath.
`make install' will do the entire job of upgrading from a previous
-installation of glibc 2.x. There may sometimes be headers left behind
-from the previous installation, but those are generally harmless. If
-you want to avoid leaving headers behind you can do things in the
-following order.
+installation of the GNU C Library version 2.x. There may sometimes be
+headers left behind from the previous installation, but those are
+generally harmless. If you want to avoid leaving headers behind you
+can do things in the following order.
You must first build the library (`make'), optionally check it
(`make check'), switch the include directories and then install (`make
library. The new `/usr/include', after switching the include
directories and before installing the library should contain the Linux
headers, but nothing else. If you do this, you will need to restore
-any headers from non-glibc libraries youself after installing the
-library.
+any headers from libraries other than the GNU C Library yourself after
+installing the library.
- You can install glibc somewhere other than where you configured it
-to go by setting the `install_root' variable on the command line for
-`make install'. The value of this variable is prepended to all the
-paths for installation. This is useful when setting up a chroot
-environment or preparing a binary distribution. The directory should be
-specified with an absolute file name.
+ You can install the GNU C Library somewhere other than where you
+configured it to go by setting the `install_root' variable on the
+command line for `make install'. The value of this variable is
+prepended to all the paths for installation. This is useful when
+setting up a chroot environment or preparing a binary distribution.
+The directory should be specified with an absolute file name.
- Glibc includes a daemon called `nscd', which you may or may not want
-to run. `nscd' caches name service lookups; it can dramatically
-improve performance with NIS+, and may help with DNS as well.
+ The GNU C Library includes a daemon called `nscd', which you may or
+may not want to run. `nscd' caches name service lookups; it can
+dramatically improve performance with NIS+, and may help with DNS as
+well.
One auxiliary program, `/usr/libexec/pt_chown', is installed setuid
-`root'. This program is invoked by the `grantpt' function; it sets the
-permissions on a pseudoterminal so it can be used by the calling
-process. This means programs like `xterm' and `screen' do not have to
-be setuid to get a pty. (There may be other reasons why they need
-privileges.) If you are using a 2.1 or newer Linux kernel with the
-`devptsfs' or `devfs' filesystems providing pty slaves, you don't need
-this program; otherwise you do. The source for `pt_chown' is in
-`login/programs/pt_chown.c'.
+`root' if the `--enable-pt_chown' configuration option is used. This
+program is invoked by the `grantpt' function; it sets the permissions
+on a pseudoterminal so it can be used by the calling process. If you
+are using a Linux kernel with the `devpts' filesystem enabled and
+mounted at `/dev/pts', you don't need this program.
After installation you might want to configure the timezone and
-locale installation of your system. The GNU C library comes with a
+locale installation of your system. The GNU C Library comes with a
locale database which gets configured with `localedef'. For example, to
set up a German locale with name `de_DE', simply issue the command
`localedef -i de_DE -f ISO-8859-1 de_DE'. To configure all locales
-that are supported by glibc, you can issue from your build directory the
-command `make localedata/install-locales'.
+that are supported by the GNU C Library, you can issue from your build
+directory the command `make localedata/install-locales'.
To configure the locally used timezone, set the `TZ' environment
variable. The script `tzselect' helps you to select the right value.
=================================
We recommend installing the following GNU tools before attempting to
-build the GNU C library:
+build the GNU C Library:
* GNU `make' 3.79 or newer
recommend GNU `make' version 3.79. All earlier versions have
severe bugs or lack features.
- * GCC 3.4 or newer, GCC 4.1 recommended
+ * GCC 4.4 or newer, GCC 4.6 recommended
- GCC 3.4 or higher is required; as of this writing, GCC 4.4 is the
- compiler we advise to use for current versions. On certain
- machines including `powerpc64', compilers prior to GCC 4.0 have
- bugs that prevent them compiling the C library code. On other
- machines, GCC 4.1 is required to build the C library with support
- for the correct `long double' type format; these include `powerpc'
- (32 bit), `s390' and `s390x'. For other architectures special
- compiler-provided headers are needed (like `cpuid.h' on x86) which
- only come with later compiler versions.
+ GCC 4.4 or higher is required; as of this writing, GCC 4.6 is the
+ compiler we advise to use to build the GNU C Library.
- You can use whatever compiler you like to compile programs that
- use GNU libc, but be aware that both GCC 2.7 and 2.8 have bugs in
- their floating-point support that may be triggered by the math
- library.
+ You can use whatever compiler you like to compile programs that use
+ the GNU C Library.
Check the FAQ for any special compiler issues on particular
platforms.
- * GNU `binutils' 2.15 or later
+ * GNU `binutils' 2.20 or later
- You must use GNU `binutils' (as and ld) to build the GNU C library.
+ You must use GNU `binutils' (as and ld) to build the GNU C Library.
No other assembler or linker has the necessary functionality at the
moment.
- * GNU `texinfo' 3.12f
+ * GNU `texinfo' 4.5 or later
To correctly translate and install the Texinfo documentation you
need this version of the `texinfo' package. Earlier versions do
installation mechanism for the info files is not present or works
differently.
- * GNU `awk' 3.0, or higher
+ * GNU `awk' 3.1.2, or higher
- `Awk' is used in several places to generate files. `gawk' 3.0 is
- known to work.
+ `awk' is used in several places to generate files. Some `gawk'
+ extensions are used, including the `asorti' function, which was
+ introduced in version 3.1.2 of `gawk'.
* Perl 5
should definitely upgrade `sed'.
-If you change any of the `configure.in' files you will also need
+If you change any of the `configure.ac' files you will also need
* GNU `autoconf' 2.53 or higher
Specific advice for GNU/Linux systems
=====================================
-If you are installing GNU libc on a GNU/Linux system, you need to have
-the header files from a 2.6.19.1 or newer kernel around for reference.
-These headers must be installed using `make headers_install'; the
-headers present in the kernel source directory are not suitable for
-direct use by GNU libc. You do not need to use that kernel, just have
-its headers installed where glibc can access them, referred to here as
-INSTALL-DIRECTORY. The easiest way to do this is to unpack it in a
-directory such as `/usr/src/linux-VERSION'. In that directory, run
-`make headers_install INSTALL_HDR_PATH=INSTALL-DIRECTORY'. Finally,
-configure glibc with the option
-`--with-headers=INSTALL-DIRECTORY/include'. Use the most recent kernel
-you can get your hands on. (If you are cross-compiling GNU libc, you
-need to specify `ARCH=ARCHITECTURE' in the `make headers_install'
-command, where ARCHITECTURE is the architecture name used by the Linux
-kernel, such as `x86' or `powerpc'.)
-
- After installing GNU libc, you may need to remove or rename
+If you are installing the GNU C Library on GNU/Linux systems, you need
+to have the header files from a 2.6.32 or newer kernel around for
+reference. These headers must be installed using `make
+headers_install'; the headers present in the kernel source directory
+are not suitable for direct use by the GNU C Library. You do not need
+to use that kernel, just have its headers installed where the GNU C
+Library can access them, referred to here as INSTALL-DIRECTORY. The
+easiest way to do this is to unpack it in a directory such as
+`/usr/src/linux-VERSION'. In that directory, run `make headers_install
+INSTALL_HDR_PATH=INSTALL-DIRECTORY'. Finally, configure the GNU C
+Library with the option `--with-headers=INSTALL-DIRECTORY/include'.
+Use the most recent kernel you can get your hands on. (If you are
+cross-compiling the GNU C Library, you need to specify
+`ARCH=ARCHITECTURE' in the `make headers_install' command, where
+ARCHITECTURE is the architecture name used by the Linux kernel, such as
+`x86' or `powerpc'.)
+
+ After installing the GNU C Library, you may need to remove or rename
directories such as `/usr/include/linux' and `/usr/include/asm', and
replace them with copies of directories such as `linux' and `asm' from
`INSTALL-DIRECTORY/include'. All directories present in
-`INSTALL-DIRECTORY/include' should be copied, except that GNU libc
-provides its own version of `/usr/include/scsi'; the files provided by
-the kernel should be copied without replacing those provided by GNU
-libc. The `linux', `asm' and `asm-generic' directories are required to
-compile programs using GNU libc; the other directories describe
-interfaces to the kernel but are not required if not compiling programs
-using those interfaces. You do not need to copy kernel headers if you
-did not specify an alternate kernel header source using
-`--with-headers'.
-
- GNU/Linux expects some components of the libc installation to be in
-`/lib' and some in `/usr/lib'. This is handled automatically if you
-configure glibc with `--prefix=/usr'. If you set some other prefix or
-allow it to default to `/usr/local', then all the components are
-installed there.
-
- You cannot use `nscd' with 2.0 kernels, due to bugs in the
-kernel-side thread support. `nscd' happens to hit these bugs
-particularly hard, but you might have problems with any threaded
-program.
+`INSTALL-DIRECTORY/include' should be copied, except that the GNU C
+Library provides its own version of `/usr/include/scsi'; the files
+provided by the kernel should be copied without replacing those
+provided by the GNU C Library. The `linux', `asm' and `asm-generic'
+directories are required to compile programs using the GNU C Library;
+the other directories describe interfaces to the kernel but are not
+required if not compiling programs using those interfaces. You do not
+need to copy kernel headers if you did not specify an alternate kernel
+header source using `--with-headers'.
+
+ The Filesystem Hierarchy Standard for GNU/Linux systems expects some
+components of the GNU C Library installation to be in `/lib' and some
+in `/usr/lib'. This is handled automatically if you configure the GNU
+C Library with `--prefix=/usr'. If you set some other prefix or allow
+it to default to `/usr/local', then all the components are installed
+there.
Reporting Bugs
==============
-There are probably bugs in the GNU C library. There are certainly
+There are probably bugs in the GNU C Library. There are certainly
errors and omissions in this manual. If you report them, they will get
fixed. If you don't, no one will ever know about them and they will
remain unfixed for all eternity, if not longer.
It is a good idea to verify that the problem has not already been
reported. Bugs are documented in two places: The file `BUGS' describes
-a number of well known bugs and the bug tracking system has a WWW
-interface at `http://sources.redhat.com/bugzilla/'. The WWW interface
-gives you access to open and closed reports. A closed report normally
-includes a patch or a hint on solving the problem.
+a number of well known bugs and the central GNU C Library bug tracking
+system has a WWW interface at `http://sourceware.org/bugzilla/'. The
+WWW interface gives you access to open and closed reports. A closed
+report normally includes a patch or a hint on solving the problem.
To report a bug, first you must find it. With any luck, this will
be the hard part. Once you've found a bug, make sure it's really a
-bug. A good way to do this is to see if the GNU C library behaves the
+bug. A good way to do this is to see if the GNU C Library behaves the
same way some other C library does. If so, probably you are wrong and
the libraries are right (but not necessarily). If not, one of the
-libraries is probably wrong. It might not be the GNU library. Many
+libraries is probably wrong. It might not be the GNU C Library. Many
historical Unix C libraries permit things that we don't, such as
closing a file twice.
- If you think you have found some way in which the GNU C library does
+ If you think you have found some way in which the GNU C Library does
not conform to the ISO and POSIX standards (*note Standards and
Portability::), that is definitely a bug. Report it!
call, if possible. This should not be too difficult.
The final step when you have a simple test case is to report the bug.
-Do this using the WWW interface to the bug database.
+Do this at `http://www.gnu.org/software/libc/bugs.html'.
If you are not sure how a function should behave, and this manual
doesn't tell you, that's a bug in the manual. Report that too! If the
projects / platform / upstream / glibc.git / blobdiff