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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 | ||
38 | m4_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 | ||
57 | AC_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; 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; 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 |