1# ============================================================================ 2# http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html 3# ============================================================================ 4# 5# SYNOPSIS 6# 7# AX_CXX_COMPILE_STDCXX_11([ext|noext],[mandatory|optional]) 8# 9# DESCRIPTION 10# 11# Check for baseline language coverage in the compiler for the C++11 12# standard; if necessary, add switches to CXXFLAGS to enable support. 13# 14# The first argument, if specified, indicates whether you insist on an 15# extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g. 16# -std=c++11). If neither is specified, you get whatever works, with 17# preference for an extended mode. 18# 19# The second argument, if specified 'mandatory' or if left unspecified, 20# indicates that baseline C++11 support is required and that the macro 21# should error out if no mode with that support is found. If specified 22# 'optional', then configuration proceeds regardless, after defining 23# HAVE_CXX11 if and only if a supporting mode is found. 24# 25# LICENSE 26# 27# Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com> 28# Copyright (c) 2012 Zack Weinberg <zackw@panix.com> 29# Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu> 30# 31# Copying and distribution of this file, with or without modification, are 32# permitted in any medium without royalty provided the copyright notice 33# and this notice are preserved. This file is offered as-is, without any 34# warranty. 35 36#serial 3 37 38m4_define([_AX_CXX_COMPILE_STDCXX_11_testbody], [ 39 template <typename T> 40 struct check 41 { 42 static_assert(sizeof(int) <= sizeof(T), "not big enough"); 43 }; 44 45 typedef check<check<bool>> right_angle_brackets; 46 47 int a; 48 decltype(a) b; 49 50 typedef check<int> check_type; 51 check_type c; 52 check_type&& cr = static_cast<check_type&&>(c); 53 54 auto d = a; 55]) 56 57AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [dnl 58 m4_if([$1], [], [], 59 [$1], [ext], [], 60 [$1], [noext], [], 61 [m4_fatal([invalid argument `$1' to AX_CXX_COMPILE_STDCXX_11])])dnl 62 m4_if([$2], [], [ax_cxx_compile_cxx11_required=true], 63 [$2], [mandatory], [ax_cxx_compile_cxx11_required=true], 64 [$2], [optional], [ax_cxx_compile_cxx11_required=false], 65 [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX_11])])dnl 66 AC_LANG_PUSH([C++])dnl 67 ac_success=no 68 AC_CACHE_CHECK(whether $CXX supports C++11 features by default, 69 ax_cv_cxx_compile_cxx11, 70 [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])], 71 [ax_cv_cxx_compile_cxx11=yes], 72 [ax_cv_cxx_compile_cxx11=no])]) 73 if test x$ax_cv_cxx_compile_cxx11 = xyes; then 74 ac_success=yes 75 fi 76 77 m4_if([$1], [noext], [], [dnl 78 if test x$ac_success = xno; then 79 for switch in -std=gnu++11 -std=gnu++0x; do 80 cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch]) 81 AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch, 82 $cachevar, 83 [ac_save_CXXFLAGS="$CXXFLAGS" 84 CXXFLAGS="$CXXFLAGS $switch" 85 AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])], 86 [eval $cachevar=yes], 87 [eval $cachevar=no]) 88 CXXFLAGS="$ac_save_CXXFLAGS"]) 89 if eval test x\$$cachevar = xyes; then 90 CXXFLAGS="$CXXFLAGS $switch" 91 ac_success=yes 92 break 93 fi 94 done 95 fi]) 96 97 m4_if([$1], [ext], [], [dnl 98 if test x$ac_success = xno; then 99 for switch in -std=c++11 -std=c++0x; do 100 cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch]) 101 AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch, 102 $cachevar, 103 [ac_save_CXXFLAGS="$CXXFLAGS" 104 CXXFLAGS="$CXXFLAGS $switch" 105 AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])], 106 [eval $cachevar=yes], 107 [eval $cachevar=no]) 108 CXXFLAGS="$ac_save_CXXFLAGS"]) 109 if eval test x\$$cachevar = xyes; then 110 CXXFLAGS="$CXXFLAGS $switch" 111 ac_success=yes 112 break 113 fi 114 done 115 fi]) 116 AC_LANG_POP([C++]) 117 if test x$ax_cxx_compile_cxx11_required = xtrue; then 118 if test x$ac_success = xno; then 119 AC_MSG_ERROR([*** A compiler with support for C++11 language features is required.]) 120 fi 121 else 122 if test x$ac_success = xno; then 123 HAVE_CXX11=0 124 AC_MSG_NOTICE([No compiler with C++11 support was found]) 125 else 126 HAVE_CXX11=1 127 AC_DEFINE(HAVE_CXX11,1, 128 [define if the compiler supports basic C++11 syntax]) 129 fi 130 131 AC_SUBST(HAVE_CXX11) 132 fi 133]) 134