1 # gnulib-common.m4 serial 72
2 dnl Copyright (C) 2007-2022 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
10 # is expanded unconditionally through gnulib-tool magic.
11 AC_DEFUN([gl_COMMON], [
12 dnl Use AC_REQUIRE here, so that the code is expanded once only.
13 AC_REQUIRE([gl_00GNULIB])
14 AC_REQUIRE([gl_COMMON_BODY])
15 AC_REQUIRE([gl_ZZGNULIB])
17 AC_DEFUN([gl_COMMON_BODY], [
18 AH_VERBATIM([_GL_GNUC_PREREQ],
19 [/* True if the compiler says it groks GNU C version MAJOR.MINOR. */
20 #if defined __GNUC__ && defined __GNUC_MINOR__
21 # define _GL_GNUC_PREREQ(major, minor) \
22 ((major) < __GNUC__ + ((minor) <= __GNUC_MINOR__))
24 # define _GL_GNUC_PREREQ(major, minor) 0
27 AH_VERBATIM([_Noreturn],
28 [/* The _Noreturn keyword of C11. */
30 # if (defined __cplusplus \
31 && ((201103 <= __cplusplus && !(__GNUC__ == 4 && __GNUC_MINOR__ == 7)) \
32 || (defined _MSC_VER && 1900 <= _MSC_VER)) \
34 /* [[noreturn]] is not practically usable, because with it the syntax
35 extern _Noreturn void func (...);
36 would not be valid; such a declaration would only be valid with 'extern'
37 and '_Noreturn' swapped, or without the 'extern' keyword. However, some
38 AIX system header files and several gnulib header files use precisely
39 this syntax with 'extern'. */
40 # define _Noreturn [[noreturn]]
41 # elif ((!defined __cplusplus || defined __clang__) \
42 && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) \
43 || (!defined __STRICT_ANSI__ \
44 && (_GL_GNUC_PREREQ (4, 7) \
45 || (defined __apple_build_version__ \
46 ? 6000000 <= __apple_build_version__ \
47 : 3 < __clang_major__ + (5 <= __clang_minor__))))))
48 /* _Noreturn works as-is. */
49 # elif _GL_GNUC_PREREQ (2, 8) || defined __clang__ || 0x5110 <= __SUNPRO_C
50 # define _Noreturn __attribute__ ((__noreturn__))
51 # elif 1200 <= (defined _MSC_VER ? _MSC_VER : 0)
52 # define _Noreturn __declspec (noreturn)
58 AH_VERBATIM([isoc99_inline],
59 [/* Work around a bug in Apple GCC 4.0.1 build 5465: In C99 mode, it supports
60 the ISO C 99 semantics of 'extern inline' (unlike the GNU C semantics of
61 earlier versions), but does not display it by setting __GNUC_STDC_INLINE__.
62 __APPLE__ && __MACH__ test for Mac OS X.
63 __APPLE_CC__ tests for the Apple compiler and its version.
64 __STDC_VERSION__ tests for the C99 mode. */
65 #if defined __APPLE__ && defined __MACH__ && __APPLE_CC__ >= 5465 && !defined __cplusplus && __STDC_VERSION__ >= 199901L && !defined __GNUC_STDC_INLINE__
66 # define __GNUC_STDC_INLINE__ 1
68 AH_VERBATIM([attribute],
70 #if (defined __has_attribute \
71 && (!defined __clang_minor__ \
72 || 3 < __clang_major__ + (5 <= __clang_minor__)))
73 # define _GL_HAS_ATTRIBUTE(attr) __has_attribute (__##attr##__)
75 # define _GL_HAS_ATTRIBUTE(attr) _GL_ATTR_##attr
76 # define _GL_ATTR_alloc_size _GL_GNUC_PREREQ (4, 3)
77 # define _GL_ATTR_always_inline _GL_GNUC_PREREQ (3, 2)
78 # define _GL_ATTR_artificial _GL_GNUC_PREREQ (4, 3)
79 # define _GL_ATTR_cold _GL_GNUC_PREREQ (4, 3)
80 # define _GL_ATTR_const _GL_GNUC_PREREQ (2, 95)
81 # define _GL_ATTR_deprecated _GL_GNUC_PREREQ (3, 1)
82 # define _GL_ATTR_diagnose_if 0
83 # define _GL_ATTR_error _GL_GNUC_PREREQ (4, 3)
84 # define _GL_ATTR_externally_visible _GL_GNUC_PREREQ (4, 1)
85 # define _GL_ATTR_fallthrough _GL_GNUC_PREREQ (7, 0)
86 # define _GL_ATTR_format _GL_GNUC_PREREQ (2, 7)
87 # define _GL_ATTR_leaf _GL_GNUC_PREREQ (4, 6)
88 # define _GL_ATTR_malloc _GL_GNUC_PREREQ (3, 0)
90 # define _GL_ATTR_may_alias 0
92 # define _GL_ATTR_may_alias _GL_GNUC_PREREQ (3, 3)
94 # define _GL_ATTR_noinline _GL_GNUC_PREREQ (3, 1)
95 # define _GL_ATTR_nonnull _GL_GNUC_PREREQ (3, 3)
96 # define _GL_ATTR_nonstring _GL_GNUC_PREREQ (8, 0)
97 # define _GL_ATTR_nothrow _GL_GNUC_PREREQ (3, 3)
98 # define _GL_ATTR_packed _GL_GNUC_PREREQ (2, 7)
99 # define _GL_ATTR_pure _GL_GNUC_PREREQ (2, 96)
100 # define _GL_ATTR_returns_nonnull _GL_GNUC_PREREQ (4, 9)
101 # define _GL_ATTR_sentinel _GL_GNUC_PREREQ (4, 0)
102 # define _GL_ATTR_unused _GL_GNUC_PREREQ (2, 7)
103 # define _GL_ATTR_warn_unused_result _GL_GNUC_PREREQ (3, 4)
106 #ifdef __has_c_attribute
107 # define _GL_HAS_C_ATTRIBUTE(attr) __has_c_attribute (__##attr##__)
109 # define _GL_HAS_C_ATTRIBUTE(attr) 0
112 ]dnl There is no _GL_ATTRIBUTE_ALIGNED; use stdalign's _Alignas instead.
114 /* _GL_ATTRIBUTE_ALLOC_SIZE ((N)) declares that the Nth argument of the function
115 is the size of the returned memory block.
116 _GL_ATTRIBUTE_ALLOC_SIZE ((M, N)) declares that the Mth argument multiplied
117 by the Nth argument of the function is the size of the returned memory block.
119 /* Applies to: function, pointer to function, function types. */
120 #if _GL_HAS_ATTRIBUTE (alloc_size)
121 # define _GL_ATTRIBUTE_ALLOC_SIZE(args) __attribute__ ((__alloc_size__ args))
123 # define _GL_ATTRIBUTE_ALLOC_SIZE(args)
126 /* _GL_ATTRIBUTE_ALWAYS_INLINE tells that the compiler should always inline the
127 function and report an error if it cannot do so. */
128 /* Applies to: function. */
129 #if _GL_HAS_ATTRIBUTE (always_inline)
130 # define _GL_ATTRIBUTE_ALWAYS_INLINE __attribute__ ((__always_inline__))
132 # define _GL_ATTRIBUTE_ALWAYS_INLINE
135 /* _GL_ATTRIBUTE_ARTIFICIAL declares that the function is not important to show
136 in stack traces when debugging. The compiler should omit the function from
138 /* Applies to: function. */
139 #if _GL_HAS_ATTRIBUTE (artificial)
140 # define _GL_ATTRIBUTE_ARTIFICIAL __attribute__ ((__artificial__))
142 # define _GL_ATTRIBUTE_ARTIFICIAL
145 /* _GL_ATTRIBUTE_COLD declares that the function is rarely executed. */
146 /* Applies to: functions. */
147 /* Avoid __attribute__ ((cold)) on MinGW; see thread starting at
148 <https://lists.gnu.org/r/emacs-devel/2019-04/msg01152.html>.
149 Also, Oracle Studio 12.6 requires 'cold' not '__cold__'. */
150 #if _GL_HAS_ATTRIBUTE (cold) && !defined __MINGW32__
152 # define _GL_ATTRIBUTE_COLD __attribute__ ((__cold__))
154 # define _GL_ATTRIBUTE_COLD __attribute__ ((cold))
157 # define _GL_ATTRIBUTE_COLD
160 /* _GL_ATTRIBUTE_CONST declares that it is OK for a compiler to omit duplicate
161 calls to the function with the same arguments.
162 This attribute is safe for a function that neither depends on nor affects
163 observable state, and always returns exactly once - e.g., does not loop
164 forever, and does not call longjmp.
165 (This attribute is stricter than _GL_ATTRIBUTE_PURE.) */
166 /* Applies to: functions. */
167 #if _GL_HAS_ATTRIBUTE (const)
168 # define _GL_ATTRIBUTE_CONST __attribute__ ((__const__))
170 # define _GL_ATTRIBUTE_CONST
173 /* _GL_ATTRIBUTE_DEALLOC (F, I) declares that the function returns pointers
174 that can be freed by passing them as the Ith argument to the
176 _GL_ATTRIBUTE_DEALLOC_FREE declares that the function returns pointers that
177 can be freed via 'free'; it can be used only after declaring 'free'. */
178 /* Applies to: functions. Cannot be used on inline functions. */
179 #if _GL_GNUC_PREREQ (11, 0)
180 # define _GL_ATTRIBUTE_DEALLOC(f, i) __attribute__ ((__malloc__ (f, i)))
182 # define _GL_ATTRIBUTE_DEALLOC(f, i)
184 /* If gnulib's <string.h> or <wchar.h> has already defined this macro, continue
185 to use this earlier definition, since <stdlib.h> may not have been included
187 #ifndef _GL_ATTRIBUTE_DEALLOC_FREE
188 # define _GL_ATTRIBUTE_DEALLOC_FREE _GL_ATTRIBUTE_DEALLOC (free, 1)
191 /* _GL_ATTRIBUTE_DEPRECATED: Declares that an entity is deprecated.
192 The compiler may warn if the entity is used. */
194 - function, variable,
195 - struct, union, struct/union member,
196 - enumeration, enumeration item,
198 in C++ also: namespace, class, template specialization. */
199 #if _GL_HAS_C_ATTRIBUTE (deprecated)
200 # define _GL_ATTRIBUTE_DEPRECATED [[__deprecated__]]
201 #elif _GL_HAS_ATTRIBUTE (deprecated)
202 # define _GL_ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
204 # define _GL_ATTRIBUTE_DEPRECATED
207 /* _GL_ATTRIBUTE_ERROR(msg) requests an error if a function is called and
208 the function call is not optimized away.
209 _GL_ATTRIBUTE_WARNING(msg) requests a warning if a function is called and
210 the function call is not optimized away. */
211 /* Applies to: functions. */
212 #if _GL_HAS_ATTRIBUTE (error)
213 # define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__error__ (msg)))
214 # define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__warning__ (msg)))
215 #elif _GL_HAS_ATTRIBUTE (diagnose_if)
216 # define _GL_ATTRIBUTE_ERROR(msg) __attribute__ ((__diagnose_if__ (1, msg, "error")))
217 # define _GL_ATTRIBUTE_WARNING(msg) __attribute__ ((__diagnose_if__ (1, msg, "warning")))
219 # define _GL_ATTRIBUTE_ERROR(msg)
220 # define _GL_ATTRIBUTE_WARNING(msg)
223 /* _GL_ATTRIBUTE_EXTERNALLY_VISIBLE declares that the entity should remain
224 visible to debuggers etc., even with '-fwhole-program'. */
225 /* Applies to: functions, variables. */
226 #if _GL_HAS_ATTRIBUTE (externally_visible)
227 # define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE __attribute__ ((externally_visible))
229 # define _GL_ATTRIBUTE_EXTERNALLY_VISIBLE
232 /* _GL_ATTRIBUTE_FALLTHROUGH declares that it is not a programming mistake if
233 the control flow falls through to the immediately following 'case' or
234 'default' label. The compiler should not warn in this case. */
235 /* Applies to: Empty statement (;), inside a 'switch' statement. */
236 /* Always expands to something. */
237 #if _GL_HAS_C_ATTRIBUTE (fallthrough)
238 # define _GL_ATTRIBUTE_FALLTHROUGH [[__fallthrough__]]
239 #elif _GL_HAS_ATTRIBUTE (fallthrough)
240 # define _GL_ATTRIBUTE_FALLTHROUGH __attribute__ ((__fallthrough__))
242 # define _GL_ATTRIBUTE_FALLTHROUGH ((void) 0)
245 /* _GL_ATTRIBUTE_FORMAT ((ARCHETYPE, STRING-INDEX, FIRST-TO-CHECK))
246 declares that the STRING-INDEXth function argument is a format string of
247 style ARCHETYPE, which is one of:
250 strftime, gnu_strftime,
252 or the same thing prefixed and suffixed with '__'.
253 If FIRST-TO-CHECK is not 0, arguments starting at FIRST-TO_CHECK
254 are suitable for the format string. */
255 /* Applies to: functions. */
256 #if _GL_HAS_ATTRIBUTE (format)
257 # define _GL_ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
259 # define _GL_ATTRIBUTE_FORMAT(spec)
262 /* _GL_ATTRIBUTE_LEAF declares that if the function is called from some other
263 compilation unit, it executes code from that unit only by return or by
264 exception handling. This declaration lets the compiler optimize that unit
265 more aggressively. */
266 /* Applies to: functions. */
267 #if _GL_HAS_ATTRIBUTE (leaf)
268 # define _GL_ATTRIBUTE_LEAF __attribute__ ((__leaf__))
270 # define _GL_ATTRIBUTE_LEAF
273 /* _GL_ATTRIBUTE_MALLOC declares that the function returns a pointer to freshly
275 /* Applies to: functions. */
276 #if _GL_HAS_ATTRIBUTE (malloc)
277 # define _GL_ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
279 # define _GL_ATTRIBUTE_MALLOC
282 /* _GL_ATTRIBUTE_MAY_ALIAS declares that pointers to the type may point to the
283 same storage as pointers to other types. Thus this declaration disables
284 strict aliasing optimization. */
285 /* Applies to: types. */
286 /* Oracle Studio 12.6 mishandles may_alias despite __has_attribute OK. */
287 #if _GL_HAS_ATTRIBUTE (may_alias) && !defined __SUNPRO_C
288 # define _GL_ATTRIBUTE_MAY_ALIAS __attribute__ ((__may_alias__))
290 # define _GL_ATTRIBUTE_MAY_ALIAS
293 /* _GL_ATTRIBUTE_MAYBE_UNUSED declares that it is not a programming mistake if
294 the entity is not used. The compiler should not warn if the entity is not
297 - function, variable,
298 - struct, union, struct/union member,
299 - enumeration, enumeration item,
301 in C++ also: class. */
302 /* In C++ and C2x, this is spelled [[__maybe_unused__]].
303 GCC's syntax is __attribute__ ((__unused__)).
304 clang supports both syntaxes. */
305 #if _GL_HAS_C_ATTRIBUTE (maybe_unused)
306 # define _GL_ATTRIBUTE_MAYBE_UNUSED [[__maybe_unused__]]
308 # define _GL_ATTRIBUTE_MAYBE_UNUSED _GL_ATTRIBUTE_UNUSED
310 /* Alternative spelling of this macro, for convenience. */
311 #define _GL_UNUSED _GL_ATTRIBUTE_MAYBE_UNUSED
312 /* Earlier spellings of this macro. */
313 #define _UNUSED_PARAMETER_ _GL_ATTRIBUTE_MAYBE_UNUSED
315 /* _GL_ATTRIBUTE_NODISCARD declares that the caller of the function should not
316 discard the return value. The compiler may warn if the caller does not use
317 the return value, unless the caller uses something like ignore_value. */
318 /* Applies to: function, enumeration, class. */
319 #if _GL_HAS_C_ATTRIBUTE (nodiscard)
320 # define _GL_ATTRIBUTE_NODISCARD [[__nodiscard__]]
321 #elif _GL_HAS_ATTRIBUTE (warn_unused_result)
322 # define _GL_ATTRIBUTE_NODISCARD __attribute__ ((__warn_unused_result__))
324 # define _GL_ATTRIBUTE_NODISCARD
327 /* _GL_ATTRIBUTE_NOINLINE tells that the compiler should not inline the
329 /* Applies to: functions. */
330 #if _GL_HAS_ATTRIBUTE (noinline)
331 # define _GL_ATTRIBUTE_NOINLINE __attribute__ ((__noinline__))
333 # define _GL_ATTRIBUTE_NOINLINE
336 /* _GL_ATTRIBUTE_NONNULL ((N1, N2,...)) declares that the arguments N1, N2,...
338 _GL_ATTRIBUTE_NONNULL () declares that all pointer arguments must not be
340 /* Applies to: functions. */
341 #if _GL_HAS_ATTRIBUTE (nonnull)
342 # define _GL_ATTRIBUTE_NONNULL(args) __attribute__ ((__nonnull__ args))
344 # define _GL_ATTRIBUTE_NONNULL(args)
347 /* _GL_ATTRIBUTE_NONSTRING declares that the contents of a character array is
348 not meant to be NUL-terminated. */
349 /* Applies to: struct/union members and variables that are arrays of element
350 type '[[un]signed] char'. */
351 #if _GL_HAS_ATTRIBUTE (nonstring)
352 # define _GL_ATTRIBUTE_NONSTRING __attribute__ ((__nonstring__))
354 # define _GL_ATTRIBUTE_NONSTRING
357 /* There is no _GL_ATTRIBUTE_NORETURN; use _Noreturn instead. */
359 /* _GL_ATTRIBUTE_NOTHROW declares that the function does not throw exceptions.
361 /* Applies to: functions. */
362 #if _GL_HAS_ATTRIBUTE (nothrow) && !defined __cplusplus
363 # define _GL_ATTRIBUTE_NOTHROW __attribute__ ((__nothrow__))
365 # define _GL_ATTRIBUTE_NOTHROW
368 /* _GL_ATTRIBUTE_PACKED declares:
369 For struct members: The member has the smallest possible alignment.
370 For struct, union, class: All members have the smallest possible alignment,
371 minimizing the memory required. */
372 /* Applies to: struct members, struct, union,
373 in C++ also: class. */
374 #if _GL_HAS_ATTRIBUTE (packed)
375 # define _GL_ATTRIBUTE_PACKED __attribute__ ((__packed__))
377 # define _GL_ATTRIBUTE_PACKED
380 /* _GL_ATTRIBUTE_PURE declares that It is OK for a compiler to omit duplicate
381 calls to the function with the same arguments if observable state is not
382 changed between calls.
383 This attribute is safe for a function that does not affect
384 observable state, and always returns exactly once.
385 (This attribute is looser than _GL_ATTRIBUTE_CONST.) */
386 /* Applies to: functions. */
387 #if _GL_HAS_ATTRIBUTE (pure)
388 # define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__))
390 # define _GL_ATTRIBUTE_PURE
393 /* _GL_ATTRIBUTE_RETURNS_NONNULL declares that the function's return value is
394 a non-NULL pointer. */
395 /* Applies to: functions. */
396 #if _GL_HAS_ATTRIBUTE (returns_nonnull)
397 # define _GL_ATTRIBUTE_RETURNS_NONNULL __attribute__ ((__returns_nonnull__))
399 # define _GL_ATTRIBUTE_RETURNS_NONNULL
402 /* _GL_ATTRIBUTE_SENTINEL(pos) declares that the variadic function expects a
403 trailing NULL argument.
404 _GL_ATTRIBUTE_SENTINEL () - The last argument is NULL (requires C99).
405 _GL_ATTRIBUTE_SENTINEL ((N)) - The (N+1)st argument from the end is NULL. */
406 /* Applies to: functions. */
407 #if _GL_HAS_ATTRIBUTE (sentinel)
408 # define _GL_ATTRIBUTE_SENTINEL(pos) __attribute__ ((__sentinel__ pos))
410 # define _GL_ATTRIBUTE_SENTINEL(pos)
413 /* A helper macro. Don't use it directly. */
414 #if _GL_HAS_ATTRIBUTE (unused)
415 # define _GL_ATTRIBUTE_UNUSED __attribute__ ((__unused__))
417 # define _GL_ATTRIBUTE_UNUSED
420 ]dnl There is no _GL_ATTRIBUTE_VISIBILITY; see m4/visibility.m4 instead.
422 /* _GL_UNUSED_LABEL; declares that it is not a programming mistake if the
423 immediately preceding label is not used. The compiler should not warn
424 if the label is not used. */
425 /* Applies to: label (both in C and C++). */
426 /* Note that g++ < 4.5 does not support the '__attribute__ ((__unused__)) ;'
427 syntax. But clang does. */
428 #if !(defined __cplusplus && !_GL_GNUC_PREREQ (4, 5)) || defined __clang__
429 # define _GL_UNUSED_LABEL _GL_ATTRIBUTE_UNUSED
431 # define _GL_UNUSED_LABEL
434 AH_VERBATIM([async_safe],
435 [/* The _GL_ASYNC_SAFE marker should be attached to functions that are
436 signal handlers (for signals other than SIGABRT, SIGPIPE) or can be
437 invoked from such signal handlers. Such functions have some restrictions:
438 * All functions that it calls should be marked _GL_ASYNC_SAFE as well,
439 or should be listed as async-signal-safe in POSIX
440 <https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04>
441 section 2.4.3. Note that malloc(), sprintf(), and fwrite(), in
442 particular, are NOT async-signal-safe.
443 * All memory locations (variables and struct fields) that these functions
444 access must be marked 'volatile'. This holds for both read and write
445 accesses. Otherwise the compiler might optimize away stores to and
446 reads from such locations that occur in the program, depending on its
447 data flow analysis. For example, when the program contains a loop
448 that is intended to inspect a variable set from within a signal handler
449 while (!signal_occurred)
451 the compiler is allowed to transform this into an endless loop if the
452 variable 'signal_occurred' is not declared 'volatile'.
453 Additionally, recall that:
454 * A signal handler should not modify errno (except if it is a handler
455 for a fatal signal and ends by raising the same signal again, thus
456 provoking the termination of the process). If it invokes a function
457 that may clobber errno, it needs to save and restore the value of
459 #define _GL_ASYNC_SAFE
461 AH_VERBATIM([micro_optimizations],
462 [/* _GL_CMP (n1, n2) performs a three-valued comparison on n1 vs. n2, where
463 n1 and n2 are expressions without side effects, that evaluate to real
464 numbers (excluding NaN).
469 The naïve code (n1 > n2 ? 1 : n1 < n2 ? -1 : 0) produces a conditional
470 jump with nearly all GCC versions up to GCC 10.
471 This variant (n1 < n2 ? -1 : n1 > n2) produces a conditional with many
472 GCC versions up to GCC 9.
473 The better code (n1 > n2) - (n1 < n2) from Hacker's Delight § 2-9
474 avoids conditional jumps in all GCC versions >= 3.4. */
475 #define _GL_CMP(n1, n2) (((n1) > (n2)) - ((n1) < (n2)))
477 dnl Hint which direction to take regarding cross-compilation guesses:
478 dnl When a user installs a program on a platform they are not intimately
479 dnl familiar with, --enable-cross-guesses=conservative is the appropriate
480 dnl choice. It implements the "If we don't know, assume the worst" principle.
481 dnl However, when an operating system developer (on a platform which is not
482 dnl yet known to gnulib) builds packages for their platform, they want to
483 dnl expose, not hide, possible platform bugs; in this case,
484 dnl --enable-cross-guesses=risky is the appropriate choice.
485 dnl Sets the variables
486 dnl gl_cross_guess_normal (to be used when 'yes' is good and 'no' is bad),
487 dnl gl_cross_guess_inverted (to be used when 'no' is good and 'yes' is bad).
488 AC_ARG_ENABLE([cross-guesses],
489 [AS_HELP_STRING([--enable-cross-guesses={conservative|risky}],
490 [specify policy for cross-compilation guesses])],
491 [if test "x$enableval" != xconservative && test "x$enableval" != xrisky; then
492 AC_MSG_WARN([invalid argument supplied to --enable-cross-guesses])
493 enableval=conservative
495 gl_cross_guesses="$enableval"],
496 [gl_cross_guesses=conservative])
497 if test $gl_cross_guesses = risky; then
498 gl_cross_guess_normal="guessing yes"
499 gl_cross_guess_inverted="guessing no"
501 gl_cross_guess_normal="guessing no"
502 gl_cross_guess_inverted="guessing yes"
504 dnl Preparation for running test programs:
505 dnl Tell glibc to write diagnostics from -D_FORTIFY_SOURCE=2 to stderr, not
506 dnl to /dev/tty, so they can be redirected to log files. Such diagnostics
507 dnl arise e.g., in the macros gl_PRINTF_DIRECTIVE_N, gl_SNPRINTF_DIRECTIVE_N.
509 export LIBC_FATAL_STDERR_
512 # gl_MODULE_INDICATOR_INIT_VARIABLE([variablename])
513 # gl_MODULE_INDICATOR_INIT_VARIABLE([variablename], [initialvalue])
514 # initializes the shell variable that indicates the presence of the given module
515 # as a C preprocessor expression.
516 AC_DEFUN([gl_MODULE_INDICATOR_INIT_VARIABLE],
518 GL_MODULE_INDICATOR_PREFIX[]_[$1]=m4_if([$2], , [0], [$2])
519 AC_SUBST(GL_MODULE_INDICATOR_PREFIX[]_[$1])
522 # gl_MODULE_INDICATOR_CONDITION
523 # expands to a C preprocessor expression that evaluates to 1 or 0, depending
524 # whether a gnulib module that has been requested shall be considered present
526 m4_define([gl_MODULE_INDICATOR_CONDITION], [1])
528 # gl_MODULE_INDICATOR_SET_VARIABLE([modulename])
529 # sets the shell variable that indicates the presence of the given module to
530 # a C preprocessor expression that will evaluate to 1.
531 AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE],
533 gl_MODULE_INDICATOR_SET_VARIABLE_AUX(
534 [GL_MODULE_INDICATOR_PREFIX[]_GNULIB_[]m4_translit([[$1]],
535 [abcdefghijklmnopqrstuvwxyz./-],
536 [ABCDEFGHIJKLMNOPQRSTUVWXYZ___])],
537 [gl_MODULE_INDICATOR_CONDITION])
540 # gl_MODULE_INDICATOR_SET_VARIABLE_AUX([variable])
541 # modifies the shell variable to include the gl_MODULE_INDICATOR_CONDITION.
542 # The shell variable's value is a C preprocessor expression that evaluates
544 AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE_AUX],
546 m4_if(m4_defn([gl_MODULE_INDICATOR_CONDITION]), [1],
548 dnl Simplify the expression VALUE || 1 to 1.
551 [gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR([$1],
552 [gl_MODULE_INDICATOR_CONDITION])])
555 # gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR([variable], [condition])
556 # modifies the shell variable to include the given condition. The shell
557 # variable's value is a C preprocessor expression that evaluates to 0 or 1.
558 AC_DEFUN([gl_MODULE_INDICATOR_SET_VARIABLE_AUX_OR],
560 dnl Simplify the expression 1 || CONDITION to 1.
561 if test "$[]$1" != 1; then
562 dnl Simplify the expression 0 || CONDITION to CONDITION.
563 if test "$[]$1" = 0; then
571 # gl_MODULE_INDICATOR([modulename])
572 # defines a C macro indicating the presence of the given module
573 # in a location where it can be used.
575 # | in lib/ | in tests/ |
576 # --------------------------------------------+---------+-----------+
577 # Module present among main modules: | 1 | 1 |
578 # --------------------------------------------+---------+-----------+
579 # Module present among tests-related modules: | 0 | 1 |
580 # --------------------------------------------+---------+-----------+
581 # Module not present at all: | 0 | 0 |
582 # --------------------------------------------+---------+-----------+
583 AC_DEFUN([gl_MODULE_INDICATOR],
585 AC_DEFINE_UNQUOTED([GNULIB_]m4_translit([[$1]],
586 [abcdefghijklmnopqrstuvwxyz./-],
587 [ABCDEFGHIJKLMNOPQRSTUVWXYZ___]),
588 [gl_MODULE_INDICATOR_CONDITION],
589 [Define to a C preprocessor expression that evaluates to 1 or 0,
590 depending whether the gnulib module $1 shall be considered present.])
593 # gl_MODULE_INDICATOR_FOR_TESTS([modulename])
594 # defines a C macro indicating the presence of the given module
595 # in lib or tests. This is useful to determine whether the module
598 # | in lib/ | in tests/ |
599 # --------------------------------------------+---------+-----------+
600 # Module present among main modules: | 1 | 1 |
601 # --------------------------------------------+---------+-----------+
602 # Module present among tests-related modules: | 1 | 1 |
603 # --------------------------------------------+---------+-----------+
604 # Module not present at all: | 0 | 0 |
605 # --------------------------------------------+---------+-----------+
606 AC_DEFUN([gl_MODULE_INDICATOR_FOR_TESTS],
608 AC_DEFINE([GNULIB_TEST_]m4_translit([[$1]],
609 [abcdefghijklmnopqrstuvwxyz./-],
610 [ABCDEFGHIJKLMNOPQRSTUVWXYZ___]), [1],
611 [Define to 1 when the gnulib module $1 should be tested.])
614 # gl_ASSERT_NO_GNULIB_POSIXCHECK
615 # asserts that there will never be a need to #define GNULIB_POSIXCHECK.
616 # and thereby enables an optimization of configure and config.h.
618 AC_DEFUN([gl_ASSERT_NO_GNULIB_POSIXCHECK],
620 dnl Override gl_WARN_ON_USE_PREPARE.
621 dnl But hide this definition from 'aclocal'.
622 AC_DEFUN([gl_W][ARN_ON_USE_PREPARE], [])
625 # gl_ASSERT_NO_GNULIB_TESTS
626 # asserts that there will be no gnulib tests in the scope of the configure.ac
627 # and thereby enables an optimization of config.h.
629 AC_DEFUN([gl_ASSERT_NO_GNULIB_TESTS],
631 dnl Override gl_MODULE_INDICATOR_FOR_TESTS.
632 AC_DEFUN([gl_MODULE_INDICATOR_FOR_TESTS], [])
635 # Test whether <features.h> exists.
636 # Set HAVE_FEATURES_H.
637 AC_DEFUN([gl_FEATURES_H],
639 AC_CHECK_HEADERS_ONCE([features.h])
640 if test $ac_cv_header_features_h = yes; then
645 AC_SUBST([HAVE_FEATURES_H])
649 # Modifies the value of the shell variable CC in an attempt to make $CC
650 # understand ISO C99 source code.
651 AC_DEFUN([gl_PROG_CC_C99],
653 dnl Just use AC_PROG_CC_C99.
654 dnl When AC_PROG_CC_C99 and AC_PROG_CC_STDC are used together, the substituted
655 dnl value of CC will contain the C99 enabling options twice. But this is only
656 dnl a cosmetic problem.
657 dnl With Autoconf >= 2.70, use AC_PROG_CC since it implies AC_PROG_CC_C99;
658 dnl this avoids a "warning: The macro `AC_PROG_CC_C99' is obsolete."
659 m4_version_prereq([2.70],
660 [AC_REQUIRE([AC_PROG_CC])],
661 [AC_REQUIRE([AC_PROG_CC_C99])])
665 # Determines the values for AR, ARFLAGS, RANLIB that fit with the compiler.
666 # The user can set the variables AR, ARFLAGS, RANLIB if he wants to override
668 AC_DEFUN([gl_PROG_AR_RANLIB],
670 dnl Minix 3 comes with two toolchains: The Amsterdam Compiler Kit compiler
671 dnl as "cc", and GCC as "gcc". They have different object file formats and
672 dnl library formats. In particular, the GNU binutils programs ar and ranlib
673 dnl produce libraries that work only with gcc, not with cc.
674 AC_REQUIRE([AC_PROG_CC])
675 dnl The '][' hides this use from 'aclocal'.
676 AC_BEFORE([$0], [A][M_PROG_AR])
677 AC_CACHE_CHECK([for Minix Amsterdam compiler], [gl_cv_c_amsterdam_compiler],
679 AC_EGREP_CPP([Amsterdam],
685 [gl_cv_c_amsterdam_compiler=yes],
686 [gl_cv_c_amsterdam_compiler=no])
689 dnl Don't compete with AM_PROG_AR's decision about AR/ARFLAGS if we are not
690 dnl building with __ACK__.
691 if test $gl_cv_c_amsterdam_compiler = yes; then
692 if test -z "$AR"; then
695 if test -z "$ARFLAGS"; then
699 dnl AM_PROG_AR was added in automake v1.11.2. AM_PROG_AR does not AC_SUBST
700 dnl ARFLAGS variable (it is filed into Makefile.in directly by automake
701 dnl script on-demand, if not specified by ./configure of course).
702 dnl Don't AC_REQUIRE the AM_PROG_AR otherwise the code for __ACK__ above
703 dnl will be ignored. Also, pay attention to call AM_PROG_AR in else block
704 dnl because AM_PROG_AR is written so it could re-set AR variable even for
705 dnl __ACK__. It may seem like its easier to avoid calling the macro here,
706 dnl but we need to AC_SUBST both AR/ARFLAGS (thus those must have some good
707 dnl default value and automake should usually know them).
709 dnl The '][' hides this use from 'aclocal'.
710 m4_ifdef([A][M_PROG_AR], [A][M_PROG_AR], [:])
713 dnl In case the code above has not helped with setting AR/ARFLAGS, use
714 dnl Automake-documented default values for AR and ARFLAGS, but prefer
715 dnl ${host}-ar over ar (useful for cross-compiling).
716 AC_CHECK_TOOL([AR], [ar], [ar])
717 if test -z "$ARFLAGS"; then
723 if test -z "$RANLIB"; then
724 if test $gl_cv_c_amsterdam_compiler = yes; then
727 dnl Use the ranlib program if it is available.
735 # This definition is copied from post-2.70 Autoconf and overrides the
736 # AC_C_RESTRICT macro from autoconf 2.60..2.70.
737 m4_version_prereq([2.70.1], [], [
738 AC_DEFUN([AC_C_RESTRICT],
739 [AC_CACHE_CHECK([for C/C++ restrict keyword], [ac_cv_c_restrict],
741 # Put '__restrict__' first, to avoid problems with glibc and non-GCC; see:
742 # https://lists.gnu.org/archive/html/bug-autoconf/2016-02/msg00006.html
743 # Put 'restrict' last, because C++ lacks it.
744 for ac_kw in __restrict__ __restrict _Restrict restrict; do
747 [[typedef int *int_ptr;
748 int foo (int_ptr $ac_kw ip) { return ip[0]; }
749 int bar (int [$ac_kw]); /* Catch GCC bug 14050. */
750 int bar (int ip[$ac_kw]) { return ip[0]; }
755 return foo (t) + bar (t);
757 [ac_cv_c_restrict=$ac_kw])
758 test "$ac_cv_c_restrict" != no && break
761 AH_VERBATIM([restrict],
762 [/* Define to the equivalent of the C99 'restrict' keyword, or to
763 nothing if this is not supported. Do not define if restrict is
764 supported only directly. */
766 /* Work around a bug in older versions of Sun C++, which did not
767 #define __restrict__ or support _Restrict or __restrict__
768 even though the corresponding Sun C compiler ended up with
769 "#define restrict _Restrict" or "#define restrict __restrict__"
770 in the previous line. This workaround can be removed once
771 we assume Oracle Developer Studio 12.5 (2016) or later. */
772 #if defined __SUNPRO_CC && !defined __RESTRICT && !defined __restrict__
774 # define __restrict__
776 case $ac_cv_c_restrict in
778 no) AC_DEFINE([restrict], []) ;;
779 *) AC_DEFINE_UNQUOTED([restrict], [$ac_cv_c_restrict]) ;;
785 # is like AC_C_BIGENDIAN, except that it can be AC_REQUIREd.
786 # Note that AC_REQUIRE([AC_C_BIGENDIAN]) does not work reliably because some
787 # macros invoke AC_C_BIGENDIAN with arguments.
788 AC_DEFUN([gl_BIGENDIAN],
793 # A temporary file descriptor.
794 # Must be less than 10, because dash 0.5.8 does not support redirections
795 # with multi-digit file descriptors.
796 m4_define([GL_TMP_FD], 9)
799 # executes command, but without the normal configure output.
800 # This is useful when you want to invoke AC_CACHE_CHECK (or AC_CHECK_FUNC etc.)
801 # inside another AC_CACHE_CHECK.
802 AC_DEFUN([gl_SILENT],
804 exec GL_TMP_FD>&AS_MESSAGE_FD AS_MESSAGE_FD>/dev/null
806 exec AS_MESSAGE_FD>&GL_TMP_FD GL_TMP_FD>&-
809 # gl_CACHE_VAL_SILENT(cache-id, command-to-set-it)
810 # is like AC_CACHE_VAL(cache-id, command-to-set-it), except that it does not
811 # output a spurious "(cached)" mark in the midst of other configure output.
812 # This macro should be used instead of AC_CACHE_VAL when it is not surrounded
813 # by an AC_MSG_CHECKING/AC_MSG_RESULT pair.
814 AC_DEFUN([gl_CACHE_VAL_SILENT],
817 AC_CACHE_VAL([$1], [$2])
821 # gl_CONDITIONAL(conditional, condition)
822 # is like AM_CONDITIONAL(conditional, condition), except that it does not
824 # configure: error: conditional "..." was never defined.
825 # Usually this means the macro was only invoked conditionally.
826 # when only invoked conditionally. Instead, in that case, both the _TRUE
827 # and the _FALSE case are disabled.
828 AC_DEFUN([gl_CONDITIONAL],
830 pushdef([AC_CONFIG_COMMANDS_PRE], [:])dnl
831 AM_CONDITIONAL([$1], [$2])
832 popdef([AC_CONFIG_COMMANDS_PRE])dnl
833 if test -z "${[$1]_TRUE}" && test -z "${[$1]_FALSE}"; then
839 # gl_CC_ALLOW_WARNINGS
840 # sets and substitutes a variable GL_CFLAG_ALLOW_WARNINGS, to a $(CC) option
841 # that reverts a preceding '-Werror' option, if available.
842 # This is expected to be '-Wno-error' on gcc, clang (except clang/MSVC), xlclang
843 # and empty otherwise.
844 AC_DEFUN([gl_CC_ALLOW_WARNINGS],
846 AC_REQUIRE([AC_PROG_CC])
847 AC_CACHE_CHECK([for C compiler option to allow warnings],
850 echo 'int dummy;' > conftest.c
851 AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -c conftest.c 2>conftest1.err]) >/dev/null
852 AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -Wno-error -c conftest.c 2>conftest2.err]) >/dev/null
853 dnl Test the number of error output lines, because AIX xlc accepts the
854 dnl option '-Wno-error', just to produce a warning
855 dnl "Option -Wno-error was incorrectly specified. The option will be ignored."
857 if test $? = 0 && test `wc -l < conftest1.err` = `wc -l < conftest2.err`; then
858 gl_cv_cc_wallow='-Wno-error'
864 case "$gl_cv_cc_wallow" in
865 none) GL_CFLAG_ALLOW_WARNINGS='' ;;
866 *) GL_CFLAG_ALLOW_WARNINGS="$gl_cv_cc_wallow" ;;
868 AC_SUBST([GL_CFLAG_ALLOW_WARNINGS])
871 # gl_CXX_ALLOW_WARNINGS
872 # sets and substitutes a variable GL_CXXFLAG_ALLOW_WARNINGS, to a $(CC) option
873 # that reverts a preceding '-Werror' option, if available.
874 AC_DEFUN([gl_CXX_ALLOW_WARNINGS],
876 dnl Requires AC_PROG_CXX or gl_PROG_ANSI_CXX.
877 if test -n "$CXX" && test "$CXX" != no; then
878 AC_CACHE_CHECK([for C++ compiler option to allow warnings],
881 echo 'int dummy;' > conftest.cc
882 AC_TRY_COMMAND([${CXX-c++} $CXXFLAGS $CPPFLAGS -c conftest.cc 2>conftest1.err]) >/dev/null
883 AC_TRY_COMMAND([${CXX-c++} $CXXFLAGS $CPPFLAGS -Wno-error -c conftest.cc 2>conftest2.err]) >/dev/null
884 dnl Test the number of error output lines, because AIX xlC accepts the
885 dnl option '-Wno-error', just to produce a warning
886 dnl "Option -Wno-error was incorrectly specified. The option will be ignored."
888 if test $? = 0 && test `wc -l < conftest1.err` = `wc -l < conftest2.err`; then
889 gl_cv_cxx_wallow='-Wno-error'
891 gl_cv_cxx_wallow=none
895 case "$gl_cv_cxx_wallow" in
896 none) GL_CXXFLAG_ALLOW_WARNINGS='' ;;
897 *) GL_CXXFLAG_ALLOW_WARNINGS="$gl_cv_cxx_wallow" ;;
900 GL_CXXFLAG_ALLOW_WARNINGS=''
902 AC_SUBST([GL_CXXFLAG_ALLOW_WARNINGS])
905 # gl_CC_GNULIB_WARNINGS
906 # sets and substitutes a variable GL_CFLAG_GNULIB_WARNINGS, to a $(CC) option
907 # set that enables or disables warnings as suitable for the Gnulib coding style.
908 AC_DEFUN([gl_CC_GNULIB_WARNINGS],
910 AC_REQUIRE([gl_CC_ALLOW_WARNINGS])
911 dnl Assume that the compiler supports -Wno-* options only if it also supports
913 GL_CFLAG_GNULIB_WARNINGS=''
914 if test -n "$GL_CFLAG_ALLOW_WARNINGS"; then
915 dnl Enable these warning options:
918 dnl -Wno-cast-qual >= 3 >= 3.9
919 dnl -Wno-conversion >= 3 >= 3.9
920 dnl -Wno-float-conversion >= 4.9 >= 3.9
921 dnl -Wno-float-equal >= 3 >= 3.9
922 dnl -Wimplicit-fallthrough >= 7 >= 3.9
923 dnl -Wno-pedantic >= 4.8 >= 3.9
924 dnl -Wno-sign-compare >= 3 >= 3.9
925 dnl -Wno-sign-conversion >= 4.3 >= 3.9
926 dnl -Wno-type-limits >= 4.3 >= 3.9
927 dnl -Wno-undef >= 3 >= 3.9
928 dnl -Wno-unsuffixed-float-constants >= 4.5
929 dnl -Wno-unused-function >= 3 >= 3.9
930 dnl -Wno-unused-parameter >= 3 >= 3.9
932 cat > conftest.c <<\EOF
933 #if __GNUC__ >= 3 || (__clang_major__ + (__clang_minor__ >= 9) > 3)
940 -Wno-unused-parameter
942 #if __GNUC__ + (__GNUC_MINOR__ >= 9) > 4 || (__clang_major__ + (__clang_minor__ >= 9) > 3)
943 -Wno-float-conversion
945 #if __GNUC__ >= 7 || (__clang_major__ + (__clang_minor__ >= 9) > 3)
946 -Wimplicit-fallthrough
948 #if __GNUC__ + (__GNUC_MINOR__ >= 8) > 4 || (__clang_major__ + (__clang_minor__ >= 9) > 3)
951 #if __GNUC__ + (__GNUC_MINOR__ >= 3) > 4 || (__clang_major__ + (__clang_minor__ >= 9) > 3)
955 #if __GNUC__ + (__GNUC_MINOR__ >= 5) > 4
956 -Wno-unsuffixed-float-constants
959 gl_command="$CC $CFLAGS $CPPFLAGS -E conftest.c > conftest.out"
960 if AC_TRY_EVAL([gl_command]); then
961 gl_options=`grep -v '#' conftest.out`
962 for word in $gl_options; do
963 GL_CFLAG_GNULIB_WARNINGS="$GL_CFLAG_GNULIB_WARNINGS $word"
966 rm -f conftest.c conftest.out
968 AC_SUBST([GL_CFLAG_GNULIB_WARNINGS])
971 dnl gl_CONDITIONAL_HEADER([foo.h])
972 dnl takes a shell variable GL_GENERATE_FOO_H (with value true or false) as input
974 dnl - an AC_SUBSTed variable FOO_H that is either a file name or empty, based
975 dnl on whether GL_GENERATE_FOO_H is true or false,
976 dnl - an Automake conditional GL_GENERATE_FOO_H that evaluates to the value of
977 dnl the shell variable GL_GENERATE_FOO_H.
978 AC_DEFUN([gl_CONDITIONAL_HEADER],
980 m4_pushdef([gl_header_name], AS_TR_SH(m4_toupper($1)))
981 m4_pushdef([gl_generate_var], [GL_GENERATE_]AS_TR_SH(m4_toupper($1)))
982 m4_pushdef([gl_generate_cond], [GL_GENERATE_]AS_TR_SH(m4_toupper($1)))
983 case "$gl_generate_var" in
984 false) gl_header_name='' ;;
986 dnl It is OK to use a .h file in lib/ from within tests/, but not vice
988 if test -z "$gl_header_name"; then
989 gl_header_name="${gl_source_base_prefix}$1"
992 *) echo "*** gl_generate_var is not set correctly" 1>&2; exit 1 ;;
994 AC_SUBST(gl_header_name)
995 gl_CONDITIONAL(gl_generate_cond, [$gl_generate_var])
996 m4_popdef([gl_generate_cond])
997 m4_popdef([gl_generate_var])
998 m4_popdef([gl_header_name])
1001 dnl Expands to some code for use in .c programs that, on native Windows, defines
1002 dnl the Microsoft deprecated alias function names to the underscore-prefixed
1003 dnl actual function names. With this macro, these function names are available
1004 dnl without linking with '-loldnames' and without generating warnings.
1005 dnl Usage: Use it after all system header files are included.
1008 dnl ]GL_MDA_DEFINES[
1010 AC_DEFUN([GL_MDA_DEFINES],[
1011 AC_REQUIRE([_GL_MDA_DEFINES])
1014 AC_DEFUN([_GL_MDA_DEFINES],
1016 #if defined _WIN32 && !defined __CYGWIN__
1017 #define access _access
1018 #define chdir _chdir
1019 #define chmod _chmod
1020 #define close _close
1021 #define creat _creat
1025 #define execl _execl
1026 #define execle _execle
1027 #define execlp _execlp
1028 #define execv _execv
1029 #define execve _execve
1030 #define execvp _execvp
1031 #define execvpe _execvpe
1032 #define fcloseall _fcloseall
1034 #define fdopen _fdopen
1035 #define fileno _fileno
1037 #define getcwd _getcwd
1038 #define getpid _getpid
1040 #define isatty _isatty
1044 #define lfind _lfind
1045 #define lsearch _lsearch
1046 #define lseek _lseek
1047 #define memccpy _memccpy
1048 #define mkdir _mkdir
1049 #define mktemp _mktemp
1051 #define putenv _putenv
1054 #define rmdir _rmdir
1055 #define strdup _strdup
1057 #define tempnam _tempnam
1058 #define tzset _tzset
1059 #define umask _umask
1060 #define unlink _unlink
1061 #define utime _utime
1062 #define wcsdup _wcsdup
1063 #define write _write