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2f1d361a | 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> | |
a6c5dbbe | 30 | # Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com> |
2f1d361a | 31 | # |
32 | # Copying and distribution of this file, with or without modification, are | |
33 | # permitted in any medium without royalty provided the copyright notice | |
34 | # and this notice are preserved. This file is offered as-is, without any | |
35 | # warranty. | |
36 | ||
a6c5dbbe | 37 | #serial 10 |
2f1d361a | 38 | |
39 | m4_define([_AX_CXX_COMPILE_STDCXX_11_testbody], [[ | |
40 | template <typename T> | |
41 | struct check | |
42 | { | |
43 | static_assert(sizeof(int) <= sizeof(T), "not big enough"); | |
44 | }; | |
45 | ||
46 | struct Base { | |
47 | virtual void f() {} | |
48 | }; | |
49 | struct Child : public Base { | |
50 | virtual void f() override {} | |
51 | }; | |
52 | ||
53 | typedef check<check<bool>> right_angle_brackets; | |
54 | ||
55 | int a; | |
56 | decltype(a) b; | |
57 | ||
58 | typedef check<int> check_type; | |
59 | check_type c; | |
60 | check_type&& cr = static_cast<check_type&&>(c); | |
61 | ||
62 | auto d = a; | |
63 | auto l = [](){}; | |
a6c5dbbe PL |
64 | // Prevent Clang error: unused variable 'l' [-Werror,-Wunused-variable] |
65 | struct use_l { use_l() { l(); } }; | |
66 | ||
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 { | |
70 | struct foo {}; | |
71 | ||
72 | template<typename T> | |
73 | using member = typename T::member_type; | |
74 | ||
75 | template<typename T> | |
76 | void func(...) {} | |
77 | ||
78 | template<typename T> | |
79 | void func(member<T>*) {} | |
80 | ||
81 | void test(); | |
82 | ||
83 | void test() { | |
84 | func<foo>(0); | |
85 | } | |
86 | } | |
2f1d361a | 87 | ]]) |
88 | ||
89 | AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [dnl | |
90 | m4_if([$1], [], [], | |
91 | [$1], [ext], [], | |
92 | [$1], [noext], [], | |
93 | [m4_fatal([invalid argument `$1' to AX_CXX_COMPILE_STDCXX_11])])dnl | |
94 | m4_if([$2], [], [ax_cxx_compile_cxx11_required=true], | |
95 | [$2], [mandatory], [ax_cxx_compile_cxx11_required=true], | |
96 | [$2], [optional], [ax_cxx_compile_cxx11_required=false], | |
97 | [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX_11])]) | |
98 | AC_LANG_PUSH([C++])dnl | |
99 | ac_success=no | |
100 | AC_CACHE_CHECK(whether $CXX supports C++11 features by default, | |
101 | ax_cv_cxx_compile_cxx11, | |
102 | [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])], | |
103 | [ax_cv_cxx_compile_cxx11=yes], | |
104 | [ax_cv_cxx_compile_cxx11=no])]) | |
105 | if test x$ax_cv_cxx_compile_cxx11 = xyes; then | |
106 | ac_success=yes | |
107 | fi | |
108 | ||
109 | m4_if([$1], [noext], [], [dnl | |
110 | if test x$ac_success = xno; then | |
111 | for switch in -std=gnu++11 -std=gnu++0x; do | |
112 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch]) | |
113 | AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch, | |
114 | $cachevar, | |
115 | [ac_save_CXXFLAGS="$CXXFLAGS" | |
a6c5dbbe | 116 | CXXFLAGS="$CXXFLAGS $switch" |
2f1d361a | 117 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])], |
118 | [eval $cachevar=yes], | |
119 | [eval $cachevar=no]) | |
120 | CXXFLAGS="$ac_save_CXXFLAGS"]) | |
121 | if eval test x\$$cachevar = xyes; then | |
122 | CXXFLAGS="$CXXFLAGS $switch" | |
123 | ac_success=yes | |
124 | break | |
125 | fi | |
126 | done | |
127 | fi]) | |
128 | ||
129 | m4_if([$1], [ext], [], [dnl | |
130 | if test x$ac_success = xno; then | |
131 | for switch in -std=c++11 -std=c++0x; do | |
132 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch]) | |
133 | AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch, | |
134 | $cachevar, | |
135 | [ac_save_CXXFLAGS="$CXXFLAGS" | |
a6c5dbbe | 136 | CXXFLAGS="$CXXFLAGS $switch" |
2f1d361a | 137 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])], |
138 | [eval $cachevar=yes], | |
139 | [eval $cachevar=no]) | |
140 | CXXFLAGS="$ac_save_CXXFLAGS"]) | |
141 | if eval test x\$$cachevar = xyes; then | |
142 | CXXFLAGS="$CXXFLAGS $switch" | |
143 | ac_success=yes | |
144 | break | |
145 | fi | |
146 | done | |
147 | fi]) | |
148 | AC_LANG_POP([C++]) | |
149 | if test x$ax_cxx_compile_cxx11_required = xtrue; then | |
150 | if test x$ac_success = xno; then | |
151 | AC_MSG_ERROR([*** A compiler with support for C++11 language features is required.]) | |
152 | fi | |
153 | else | |
154 | if test x$ac_success = xno; then | |
155 | HAVE_CXX11=0 | |
156 | AC_MSG_NOTICE([No compiler with C++11 support was found]) | |
157 | else | |
158 | HAVE_CXX11=1 | |
159 | AC_DEFINE(HAVE_CXX11,1, | |
160 | [define if the compiler supports basic C++11 syntax]) | |
161 | fi | |
162 | ||
163 | AC_SUBST(HAVE_CXX11) | |
164 | fi | |
165 | ]) |