# extensions.m4 # serial 25 -*- Autoconf -*- dnl Copyright (C) 2003, 2006-2024 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. # Enable extensions on systems that normally disable them. dnl Define to empty for the benefit of Autoconf 2.69 and earlier, so that dnl AC_USE_SYSTEM_EXTENSIONS (below) can be used unchanged from Autoconf 2.70+. m4_ifndef([AC_CHECK_INCLUDES_DEFAULT], [AC_DEFUN([AC_CHECK_INCLUDES_DEFAULT], [])]) # This definition of AC_USE_SYSTEM_EXTENSIONS is stolen from git # Autoconf. Perhaps we can remove this once we can assume Autoconf # is recent-enough everywhere, but since Autoconf mutates rapidly # enough in this area it's likely we'll need to redefine # AC_USE_SYSTEM_EXTENSIONS for quite some time. # If autoconf reports a warning # warning: AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS # or warning: AC_RUN_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS # the fix is # 1) to ensure that AC_USE_SYSTEM_EXTENSIONS is never directly invoked # but always AC_REQUIREd, # 2) to ensure that for each occurrence of # AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) # or # AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) # the corresponding gnulib module description has 'extensions' among # its dependencies. This will ensure that the gl_USE_SYSTEM_EXTENSIONS # invocation occurs in gl_EARLY, not in gl_INIT. m4_version_prereq([2.72], [], [ # AC_USE_SYSTEM_EXTENSIONS # ------------------------ # Enable extensions on systems that normally disable them, # typically due to standards-conformance issues. # We unconditionally define as many of the known feature-enabling # as possible, reserving conditional behavior for macros that are # known to cause problems on some platforms (such as __EXTENSIONS__). AC_DEFUN_ONCE([AC_USE_SYSTEM_EXTENSIONS], [AC_BEFORE([$0], [AC_PREPROC_IFELSE])dnl AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl AC_BEFORE([$0], [AC_LINK_IFELSE])dnl AC_BEFORE([$0], [AC_RUN_IFELSE])dnl AC_BEFORE([$0], [AC_CHECK_INCLUDES_DEFAULT])dnl dnl #undef in AH_VERBATIM gets replaced with #define by AC_DEFINE. dnl Use a different key than __EXTENSIONS__, as that name broke existing dnl configure.ac when using autoheader 2.62. dnl The macros below are in alphabetical order ignoring leading _ or __ dnl prefixes. AH_VERBATIM([USE_SYSTEM_EXTENSIONS], [/* Enable extensions on AIX 3, Interix. */ #ifndef _ALL_SOURCE # undef _ALL_SOURCE #endif /* Enable general extensions on macOS. */ #ifndef _DARWIN_C_SOURCE # undef _DARWIN_C_SOURCE #endif /* Enable general extensions on Solaris. */ #ifndef __EXTENSIONS__ # undef __EXTENSIONS__ #endif /* Enable GNU extensions on systems that have them. */ #ifndef _GNU_SOURCE # undef _GNU_SOURCE #endif /* Enable X/Open compliant socket functions that do not require linking with -lxnet on HP-UX 11.11. */ #ifndef _HPUX_ALT_XOPEN_SOCKET_API # undef _HPUX_ALT_XOPEN_SOCKET_API #endif /* Identify the host operating system as Minix. This macro does not affect the system headers' behavior. A future release of Autoconf may stop defining this macro. */ #ifndef _MINIX # undef _MINIX #endif /* Enable general extensions on NetBSD. Enable NetBSD compatibility extensions on Minix. */ #ifndef _NETBSD_SOURCE # undef _NETBSD_SOURCE #endif /* Enable OpenBSD compatibility extensions on NetBSD. Oddly enough, this does nothing on OpenBSD. */ #ifndef _OPENBSD_SOURCE # undef _OPENBSD_SOURCE #endif /* Define to 1 if needed for POSIX-compatible behavior. */ #ifndef _POSIX_SOURCE # undef _POSIX_SOURCE #endif /* Define to 2 if needed for POSIX-compatible behavior. */ #ifndef _POSIX_1_SOURCE # undef _POSIX_1_SOURCE #endif /* Enable POSIX-compatible threading on Solaris. */ #ifndef _POSIX_PTHREAD_SEMANTICS # undef _POSIX_PTHREAD_SEMANTICS #endif /* Enable extensions specified by ISO/IEC TS 18661-5:2014. */ #ifndef __STDC_WANT_IEC_60559_ATTRIBS_EXT__ # undef __STDC_WANT_IEC_60559_ATTRIBS_EXT__ #endif /* Enable extensions specified by ISO/IEC TS 18661-1:2014. */ #ifndef __STDC_WANT_IEC_60559_BFP_EXT__ # undef __STDC_WANT_IEC_60559_BFP_EXT__ #endif /* Enable extensions specified by ISO/IEC TS 18661-2:2015. */ #ifndef __STDC_WANT_IEC_60559_DFP_EXT__ # undef __STDC_WANT_IEC_60559_DFP_EXT__ #endif /* Enable extensions specified by C23 Annex F. */ #ifndef __STDC_WANT_IEC_60559_EXT__ # undef __STDC_WANT_IEC_60559_EXT__ #endif /* Enable extensions specified by ISO/IEC TS 18661-4:2015. */ #ifndef __STDC_WANT_IEC_60559_FUNCS_EXT__ # undef __STDC_WANT_IEC_60559_FUNCS_EXT__ #endif /* Enable extensions specified by C23 Annex H and ISO/IEC TS 18661-3:2015. */ #ifndef __STDC_WANT_IEC_60559_TYPES_EXT__ # undef __STDC_WANT_IEC_60559_TYPES_EXT__ #endif /* Enable extensions specified by ISO/IEC TR 24731-2:2010. */ #ifndef __STDC_WANT_LIB_EXT2__ # undef __STDC_WANT_LIB_EXT2__ #endif /* Enable extensions specified by ISO/IEC 24747:2009. */ #ifndef __STDC_WANT_MATH_SPEC_FUNCS__ # undef __STDC_WANT_MATH_SPEC_FUNCS__ #endif /* Enable extensions on HP NonStop. */ #ifndef _TANDEM_SOURCE # undef _TANDEM_SOURCE #endif /* Enable X/Open extensions. Define to 500 only if necessary to make mbstate_t available. */ #ifndef _XOPEN_SOURCE # undef _XOPEN_SOURCE #endif ])dnl AC_REQUIRE([AC_CHECK_INCLUDES_DEFAULT])dnl _AC_CHECK_HEADER_ONCE([wchar.h]) _AC_CHECK_HEADER_ONCE([minix/config.h]) dnl Defining __EXTENSIONS__ may break the system headers on some systems. dnl (FIXME: Which ones?) AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__], [ac_cv_safe_to_define___extensions__], [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM([[ # define __EXTENSIONS__ 1 ]AC_INCLUDES_DEFAULT])], [ac_cv_safe_to_define___extensions__=yes], [ac_cv_safe_to_define___extensions__=no])]) dnl HP-UX 11.11 defines mbstate_t only if _XOPEN_SOURCE is defined to dnl 500, regardless of whether compiling with -Ae or -D_HPUX_SOURCE=1. dnl But defining _XOPEN_SOURCE may turn *off* extensions on platforms dnl not covered by turn-on-extensions macros (notably Dragonfly, Free, dnl and OpenBSD, which don't have any equivalent of _NETBSD_SOURCE) so dnl it should only be defined when necessary. AC_CACHE_CHECK([whether _XOPEN_SOURCE should be defined], [ac_cv_should_define__xopen_source], [ac_cv_should_define__xopen_source=no AS_IF([test $ac_cv_header_wchar_h = yes], [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM([[ #include mbstate_t x;]])], [], [AC_COMPILE_IFELSE( [AC_LANG_PROGRAM([[ #define _XOPEN_SOURCE 500 #include mbstate_t x;]])], [ac_cv_should_define__xopen_source=yes])])])]) AC_DEFINE([_ALL_SOURCE]) AC_DEFINE([_DARWIN_C_SOURCE]) AC_DEFINE([_GNU_SOURCE]) AC_DEFINE([_HPUX_ALT_XOPEN_SOCKET_API]) AC_DEFINE([_NETBSD_SOURCE]) AC_DEFINE([_OPENBSD_SOURCE]) AC_DEFINE([_POSIX_PTHREAD_SEMANTICS]) AC_DEFINE([__STDC_WANT_IEC_60559_ATTRIBS_EXT__]) AC_DEFINE([__STDC_WANT_IEC_60559_BFP_EXT__]) AC_DEFINE([__STDC_WANT_IEC_60559_DFP_EXT__]) AC_DEFINE([__STDC_WANT_IEC_60559_EXT__]) AC_DEFINE([__STDC_WANT_IEC_60559_FUNCS_EXT__]) AC_DEFINE([__STDC_WANT_IEC_60559_TYPES_EXT__]) AC_DEFINE([__STDC_WANT_LIB_EXT2__]) AC_DEFINE([__STDC_WANT_MATH_SPEC_FUNCS__]) AC_DEFINE([_TANDEM_SOURCE]) AS_IF([test $ac_cv_header_minix_config_h = yes], [MINIX=yes AC_DEFINE([_MINIX]) AC_DEFINE([_POSIX_SOURCE]) AC_DEFINE([_POSIX_1_SOURCE], [2])], [MINIX=]) AS_IF([test $ac_cv_safe_to_define___extensions__ = yes], [AC_DEFINE([__EXTENSIONS__])]) AS_IF([test $ac_cv_should_define__xopen_source = yes], [AC_DEFINE([_XOPEN_SOURCE], [500])]) ])# AC_USE_SYSTEM_EXTENSIONS ]) # gl_USE_SYSTEM_EXTENSIONS # ------------------------ # Enable extensions on systems that normally disable them, # typically due to standards-conformance issues. AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS], [ AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) dnl On OpenBSD 6.8 with GCC, the include files contain a couple of dnl definitions that are only activated with an explicit -D_ISOC11_SOURCE. dnl That's because this version of GCC (4.2.1) supports the option dnl '-std=gnu99' but not the option '-std=gnu11'. AC_REQUIRE([AC_CANONICAL_HOST]) case "$host_os" in openbsd*) AC_DEFINE([_ISOC11_SOURCE], [1], [Define to enable the declarations of ISO C 11 types and functions.]) ;; esac dnl On OpenSolaris derivatives, the include files contains a couple of dnl declarations that are only activated with an explicit dnl -D__STDC_WANT_LIB_EXT1__. AH_VERBATIM([USE_ISO_C_23_ANNEX_K_EXTENSIONS], [/* Define to enable the declarations of ISO C 23 Annex K types and functions. */ #if !(defined __STDC_WANT_LIB_EXT1__ && __STDC_WANT_LIB_EXT1__) #undef/**/__STDC_WANT_LIB_EXT1__ #define __STDC_WANT_LIB_EXT1__ 1 #endif ]) ])