2 # serial 25 -*- Autoconf -*-
3 dnl Copyright (C) 2003, 2006-2024 Free Software Foundation, Inc.
4 dnl This file is free software; the Free Software Foundation
5 dnl gives unlimited permission to copy and/or distribute it,
6 dnl with or without modifications, as long as this notice is preserved.
8 # Enable extensions on systems that normally disable them.
10 dnl Define to empty for the benefit of Autoconf 2.69 and earlier, so that
11 dnl AC_USE_SYSTEM_EXTENSIONS (below) can be used unchanged from Autoconf 2.70+.
12 m4_ifndef([AC_CHECK_INCLUDES_DEFAULT],
13 [AC_DEFUN([AC_CHECK_INCLUDES_DEFAULT], [])])
15 # This definition of AC_USE_SYSTEM_EXTENSIONS is stolen from git
16 # Autoconf. Perhaps we can remove this once we can assume Autoconf
17 # is recent-enough everywhere, but since Autoconf mutates rapidly
18 # enough in this area it's likely we'll need to redefine
19 # AC_USE_SYSTEM_EXTENSIONS for quite some time.
21 # If autoconf reports a warning
22 # warning: AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
23 # or warning: AC_RUN_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
25 # 1) to ensure that AC_USE_SYSTEM_EXTENSIONS is never directly invoked
26 # but always AC_REQUIREd,
27 # 2) to ensure that for each occurrence of
28 # AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
30 # AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
31 # the corresponding gnulib module description has 'extensions' among
32 # its dependencies. This will ensure that the gl_USE_SYSTEM_EXTENSIONS
33 # invocation occurs in gl_EARLY, not in gl_INIT.
35 m4_version_prereq([2.72], [], [
37 # AC_USE_SYSTEM_EXTENSIONS
38 # ------------------------
39 # Enable extensions on systems that normally disable them,
40 # typically due to standards-conformance issues.
41 # We unconditionally define as many of the known feature-enabling
42 # as possible, reserving conditional behavior for macros that are
43 # known to cause problems on some platforms (such as __EXTENSIONS__).
44 AC_DEFUN_ONCE([AC_USE_SYSTEM_EXTENSIONS],
45 [AC_BEFORE([$0], [AC_PREPROC_IFELSE])dnl
46 AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
47 AC_BEFORE([$0], [AC_LINK_IFELSE])dnl
48 AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
49 AC_BEFORE([$0], [AC_CHECK_INCLUDES_DEFAULT])dnl
50 dnl #undef in AH_VERBATIM gets replaced with #define by AC_DEFINE.
51 dnl Use a different key than __EXTENSIONS__, as that name broke existing
52 dnl configure.ac when using autoheader 2.62.
53 dnl The macros below are in alphabetical order ignoring leading _ or __
55 AH_VERBATIM([USE_SYSTEM_EXTENSIONS],
56 [/* Enable extensions on AIX 3, Interix. */
60 /* Enable general extensions on macOS. */
61 #ifndef _DARWIN_C_SOURCE
62 # undef _DARWIN_C_SOURCE
64 /* Enable general extensions on Solaris. */
65 #ifndef __EXTENSIONS__
66 # undef __EXTENSIONS__
68 /* Enable GNU extensions on systems that have them. */
72 /* Enable X/Open compliant socket functions that do not require linking
73 with -lxnet on HP-UX 11.11. */
74 #ifndef _HPUX_ALT_XOPEN_SOCKET_API
75 # undef _HPUX_ALT_XOPEN_SOCKET_API
77 /* Identify the host operating system as Minix.
78 This macro does not affect the system headers' behavior.
79 A future release of Autoconf may stop defining this macro. */
83 /* Enable general extensions on NetBSD.
84 Enable NetBSD compatibility extensions on Minix. */
85 #ifndef _NETBSD_SOURCE
86 # undef _NETBSD_SOURCE
88 /* Enable OpenBSD compatibility extensions on NetBSD.
89 Oddly enough, this does nothing on OpenBSD. */
90 #ifndef _OPENBSD_SOURCE
91 # undef _OPENBSD_SOURCE
93 /* Define to 1 if needed for POSIX-compatible behavior. */
97 /* Define to 2 if needed for POSIX-compatible behavior. */
98 #ifndef _POSIX_1_SOURCE
99 # undef _POSIX_1_SOURCE
101 /* Enable POSIX-compatible threading on Solaris. */
102 #ifndef _POSIX_PTHREAD_SEMANTICS
103 # undef _POSIX_PTHREAD_SEMANTICS
105 /* Enable extensions specified by ISO/IEC TS 18661-5:2014. */
106 #ifndef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
107 # undef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
109 /* Enable extensions specified by ISO/IEC TS 18661-1:2014. */
110 #ifndef __STDC_WANT_IEC_60559_BFP_EXT__
111 # undef __STDC_WANT_IEC_60559_BFP_EXT__
113 /* Enable extensions specified by ISO/IEC TS 18661-2:2015. */
114 #ifndef __STDC_WANT_IEC_60559_DFP_EXT__
115 # undef __STDC_WANT_IEC_60559_DFP_EXT__
117 /* Enable extensions specified by C23 Annex F. */
118 #ifndef __STDC_WANT_IEC_60559_EXT__
119 # undef __STDC_WANT_IEC_60559_EXT__
121 /* Enable extensions specified by ISO/IEC TS 18661-4:2015. */
122 #ifndef __STDC_WANT_IEC_60559_FUNCS_EXT__
123 # undef __STDC_WANT_IEC_60559_FUNCS_EXT__
125 /* Enable extensions specified by C23 Annex H and ISO/IEC TS 18661-3:2015. */
126 #ifndef __STDC_WANT_IEC_60559_TYPES_EXT__
127 # undef __STDC_WANT_IEC_60559_TYPES_EXT__
129 /* Enable extensions specified by ISO/IEC TR 24731-2:2010. */
130 #ifndef __STDC_WANT_LIB_EXT2__
131 # undef __STDC_WANT_LIB_EXT2__
133 /* Enable extensions specified by ISO/IEC 24747:2009. */
134 #ifndef __STDC_WANT_MATH_SPEC_FUNCS__
135 # undef __STDC_WANT_MATH_SPEC_FUNCS__
137 /* Enable extensions on HP NonStop. */
138 #ifndef _TANDEM_SOURCE
139 # undef _TANDEM_SOURCE
141 /* Enable X/Open extensions. Define to 500 only if necessary
142 to make mbstate_t available. */
143 #ifndef _XOPEN_SOURCE
144 # undef _XOPEN_SOURCE
148 AC_REQUIRE([AC_CHECK_INCLUDES_DEFAULT])dnl
149 _AC_CHECK_HEADER_ONCE([wchar.h])
150 _AC_CHECK_HEADER_ONCE([minix/config.h])
152 dnl Defining __EXTENSIONS__ may break the system headers on some systems.
153 dnl (FIXME: Which ones?)
154 AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
155 [ac_cv_safe_to_define___extensions__],
158 # define __EXTENSIONS__ 1
159 ]AC_INCLUDES_DEFAULT])],
160 [ac_cv_safe_to_define___extensions__=yes],
161 [ac_cv_safe_to_define___extensions__=no])])
163 dnl HP-UX 11.11 defines mbstate_t only if _XOPEN_SOURCE is defined to
164 dnl 500, regardless of whether compiling with -Ae or -D_HPUX_SOURCE=1.
165 dnl But defining _XOPEN_SOURCE may turn *off* extensions on platforms
166 dnl not covered by turn-on-extensions macros (notably Dragonfly, Free,
167 dnl and OpenBSD, which don't have any equivalent of _NETBSD_SOURCE) so
168 dnl it should only be defined when necessary.
169 AC_CACHE_CHECK([whether _XOPEN_SOURCE should be defined],
170 [ac_cv_should_define__xopen_source],
171 [ac_cv_should_define__xopen_source=no
172 AS_IF([test $ac_cv_header_wchar_h = yes],
180 #define _XOPEN_SOURCE 500
183 [ac_cv_should_define__xopen_source=yes])])])])
185 AC_DEFINE([_ALL_SOURCE])
186 AC_DEFINE([_DARWIN_C_SOURCE])
187 AC_DEFINE([_GNU_SOURCE])
188 AC_DEFINE([_HPUX_ALT_XOPEN_SOCKET_API])
189 AC_DEFINE([_NETBSD_SOURCE])
190 AC_DEFINE([_OPENBSD_SOURCE])
191 AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
192 AC_DEFINE([__STDC_WANT_IEC_60559_ATTRIBS_EXT__])
193 AC_DEFINE([__STDC_WANT_IEC_60559_BFP_EXT__])
194 AC_DEFINE([__STDC_WANT_IEC_60559_DFP_EXT__])
195 AC_DEFINE([__STDC_WANT_IEC_60559_EXT__])
196 AC_DEFINE([__STDC_WANT_IEC_60559_FUNCS_EXT__])
197 AC_DEFINE([__STDC_WANT_IEC_60559_TYPES_EXT__])
198 AC_DEFINE([__STDC_WANT_LIB_EXT2__])
199 AC_DEFINE([__STDC_WANT_MATH_SPEC_FUNCS__])
200 AC_DEFINE([_TANDEM_SOURCE])
201 AS_IF([test $ac_cv_header_minix_config_h = yes],
204 AC_DEFINE([_POSIX_SOURCE])
205 AC_DEFINE([_POSIX_1_SOURCE], [2])],
207 AS_IF([test $ac_cv_safe_to_define___extensions__ = yes],
208 [AC_DEFINE([__EXTENSIONS__])])
209 AS_IF([test $ac_cv_should_define__xopen_source = yes],
210 [AC_DEFINE([_XOPEN_SOURCE], [500])])
211 ])# AC_USE_SYSTEM_EXTENSIONS
214 # gl_USE_SYSTEM_EXTENSIONS
215 # ------------------------
216 # Enable extensions on systems that normally disable them,
217 # typically due to standards-conformance issues.
218 AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS],
220 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
222 dnl On OpenBSD 6.8 with GCC, the include files contain a couple of
223 dnl definitions that are only activated with an explicit -D_ISOC11_SOURCE.
224 dnl That's because this version of GCC (4.2.1) supports the option
225 dnl '-std=gnu99' but not the option '-std=gnu11'.
226 AC_REQUIRE([AC_CANONICAL_HOST])
229 AC_DEFINE([_ISOC11_SOURCE], [1],
230 [Define to enable the declarations of ISO C 11 types and functions.])
234 dnl On OpenSolaris derivatives, the include files contains a couple of
235 dnl declarations that are only activated with an explicit
236 dnl -D__STDC_WANT_LIB_EXT1__.
237 AH_VERBATIM([USE_ISO_C_23_ANNEX_K_EXTENSIONS],
238 [/* Define to enable the declarations of ISO C 23 Annex K types and functions. */
239 #if !(defined __STDC_WANT_LIB_EXT1__ && __STDC_WANT_LIB_EXT1__)
240 #undef/**/__STDC_WANT_LIB_EXT1__
241 #define __STDC_WANT_LIB_EXT1__ 1