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>
30 # Copyright (c) 2014 Alexey Sokolov <sokolov@google.com>
31 # Copyright (c) 2014, 2015 Google Inc.
32 # Copyright (c) 2015 VLC authors and VideoLAN
34 # Copying and distribution of this file, with or without modification, are
35 # permitted in any medium without royalty provided the copyright notice
36 # and this notice are preserved. This file is offered as-is, without any
41 m4_define([_AX_CXX_COMPILE_STDCXX_11_testbody], [[
45 static_assert(sizeof(int) <= sizeof(T), "not big enough");
51 struct Child : public Base {
52 virtual void f() override {}
55 typedef check<check<bool>> right_angle_brackets;
60 typedef check<int> check_type;
62 check_type&& cr = static_cast<check_type&&>(c);
67 // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
68 // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function because of this
69 namespace test_template_alias_sfinae {
73 using member = typename T::member_type;
79 void func(member<T>*) {}
87 constexpr uint64_t constantname = UINT64_C(0x100000000);
90 AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [dnl
94 [m4_fatal([invalid argument `$1' to AX_CXX_COMPILE_STDCXX_11])])dnl
95 m4_if([$2], [], [ax_cxx_compile_cxx11_required=true],
96 [$2], [mandatory], [ax_cxx_compile_cxx11_required=true],
97 [$2], [optional], [ax_cxx_compile_cxx11_required=false],
98 [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX_11])])
99 AC_LANG_PUSH([C++])dnl
101 AC_CACHE_CHECK(whether $CXX supports C++11 features by default,
102 ax_cv_cxx_compile_cxx11,
103 [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
104 [ax_cv_cxx_compile_cxx11=yes],
105 [ax_cv_cxx_compile_cxx11=no])])
106 if test x$ax_cv_cxx_compile_cxx11 = xyes; then
110 m4_if([$1], [noext], [], [dnl
111 if test x$ac_success = xno; then
112 for switch in -std=gnu++11 -std=gnu++0x; do
113 cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
114 AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
116 [ac_save_CXXFLAGS="$CXXFLAGS"
117 CXXFLAGS="$CXXFLAGS $switch"
118 AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
119 [eval $cachevar=yes],
121 CXXFLAGS="$ac_save_CXXFLAGS"])
122 if eval test x\$$cachevar = xyes; then
123 CXXFLAGS="$CXXFLAGS $switch"
130 m4_if([$1], [ext], [], [dnl
131 if test x$ac_success = xno; then
132 for switch in -std=c++11 -std=c++0x; do
133 cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
134 AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
136 [ac_save_CXXFLAGS="$CXXFLAGS"
137 CXXFLAGS="$CXXFLAGS $switch"
138 AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
139 [eval $cachevar=yes],
141 CXXFLAGS="$ac_save_CXXFLAGS"])
142 if eval test x\$$cachevar = xyes; then
143 CXXFLAGS="$CXXFLAGS $switch"
150 if test x$ax_cxx_compile_cxx11_required = xtrue; then
151 if test x$ac_success = xno; then
152 AC_MSG_ERROR([*** A compiler with support for C++11 language features is required.])
155 if test x$ac_success = xno; then
157 AC_MSG_NOTICE([No compiler with C++11 support was found])
160 AC_DEFINE(HAVE_CXX11,1,
161 [define if the compiler supports basic C++11 syntax])