1 # ============================================================================
2 # http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html
3 # ============================================================================
7 # AX_CXX_COMPILE_STDCXX_11([ext|noext],[mandatory|optional])
11 # Check for baseline language coverage in the compiler for the C++11
12 # standard; if necessary, add switches to CXXFLAGS to enable support.
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.
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.
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>
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
38 m4_define([_AX_CXX_COMPILE_STDCXX_11_testbody], [
42 static_assert(sizeof(int) <= sizeof(T), "not big enough");
45 typedef check<check<bool>> right_angle_brackets;
50 typedef check<int> check_type;
52 check_type&& cr = static_cast<check_type&&>(c);
57 AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [dnl
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
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
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 $switch,
83 [ac_save_CXXFLAGS="$CXXFLAGS"
84 CXXFLAGS="$CXXFLAGS $switch"
85 AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
88 CXXFLAGS="$ac_save_CXXFLAGS"])
89 if eval test x\$$cachevar = xyes; then
90 CXXFLAGS="$CXXFLAGS $switch"
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 $switch,
103 [ac_save_CXXFLAGS="$CXXFLAGS"
104 CXXFLAGS="$CXXFLAGS $switch"
105 AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
106 [eval $cachevar=yes],
108 CXXFLAGS="$ac_save_CXXFLAGS"])
109 if eval test x\$$cachevar = xyes; then
110 CXXFLAGS="$CXXFLAGS $switch"
117 if test x$ax_cxx_compile_cxx11_required = xtrue; then
118 if test x$ac_success = xno; then
119 AC_MSG_ERROR([*** A compiler with support for C++11 language features is required.])
122 if test x$ac_success = xno; then
124 AC_MSG_NOTICE([No compiler with C++11 support was found])
127 AC_DEFINE(HAVE_CXX11,1,
128 [define if the compiler supports basic C++11 syntax])