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4ac4a490 | 1 | ## Copyright (C) 1996-2017 The Squid Software Foundation and contributors |
5d2e6f19 AJ |
2 | ## |
3 | ## Squid software is distributed under GPLv2+ license and includes | |
4 | ## contributions from numerous individuals and organizations. | |
5 | ## Please see the COPYING and CONTRIBUTORS files for details. | |
6 | ## | |
7 | ||
ea1cf567 AJ |
8 | # ============================================================================ |
9 | # http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html | |
10 | # ============================================================================ | |
11 | # | |
12 | # SYNOPSIS | |
13 | # | |
14 | # AX_CXX_COMPILE_STDCXX_11([ext|noext],[mandatory|optional]) | |
15 | # | |
16 | # DESCRIPTION | |
17 | # | |
18 | # Check for baseline language coverage in the compiler for the C++11 | |
19 | # standard; if necessary, add switches to CXXFLAGS to enable support. | |
20 | # | |
21 | # The first argument, if specified, indicates whether you insist on an | |
22 | # extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g. | |
23 | # -std=c++11). If neither is specified, you get whatever works, with | |
24 | # preference for an extended mode. | |
25 | # | |
26 | # The second argument, if specified 'mandatory' or if left unspecified, | |
27 | # indicates that baseline C++11 support is required and that the macro | |
28 | # should error out if no mode with that support is found. If specified | |
29 | # 'optional', then configuration proceeds regardless, after defining | |
30 | # HAVE_CXX11 if and only if a supporting mode is found. | |
31 | # | |
32 | # LICENSE | |
33 | # | |
34 | # Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com> | |
35 | # Copyright (c) 2012 Zack Weinberg <zackw@panix.com> | |
36 | # Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu> | |
37 | # Copyright (c) 2014 Alexey Sokolov <sokolov@google.com> | |
38 | # | |
39 | # Copying and distribution of this file, with or without modification, are | |
40 | # permitted in any medium without royalty provided the copyright notice | |
41 | # and this notice are preserved. This file is offered as-is, without any | |
42 | # warranty. | |
43 | ||
44 | #serial 4 | |
45 | ||
46 | m4_define([_AX_CXX_COMPILE_STDCXX_11_testbody], [[ | |
e4dffe5a | 47 | template <typename T> |
ea1cf567 AJ |
48 | struct check |
49 | { | |
e4dffe5a | 50 | static_assert(sizeof(int) <= sizeof(T), "not big enough"); // GCC 4.3+ |
ea1cf567 AJ |
51 | }; |
52 | ||
e4dffe5a | 53 | #if WHEN_SQUID_HAS_MANDATORY_GCC_4_789_SUPPORT |
ea1cf567 AJ |
54 | struct Base { |
55 | virtual void f() {} | |
56 | }; | |
57 | struct Child : public Base { | |
e4dffe5a | 58 | virtual void f() override {} // GCC 4.7+ |
ea1cf567 | 59 | }; |
e4dffe5a | 60 | #endif |
ea1cf567 | 61 | |
e4dffe5a | 62 | typedef check<check<bool>> right_angle_brackets; // GCC 4.3+ |
ea1cf567 AJ |
63 | |
64 | int a; | |
e4dffe5a | 65 | decltype(a) b; // GCC 4.3+ |
ea1cf567 AJ |
66 | |
67 | typedef check<int> check_type; | |
68 | check_type c; | |
e4dffe5a | 69 | check_type&& cr = static_cast<check_type&&>(c); // GCC 4.3+ |
ea1cf567 | 70 | |
e4dffe5a AJ |
71 | auto d = a; // GCC 4.4+ |
72 | #if WHEN_SQUID_HAS_MANDATORY_GCC_4_789_SUPPORT | |
73 | auto l = [](){}; // GCC 4.5+ (void lambda seems not to be documented) | |
74 | #endif | |
ea1cf567 AJ |
75 | ]]) |
76 | ||
77 | AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [dnl | |
78 | m4_if([$1], [], [], | |
79 | [$1], [ext], [], | |
80 | [$1], [noext], [], | |
81 | [m4_fatal([invalid argument `$1' to AX_CXX_COMPILE_STDCXX_11])])dnl | |
82 | m4_if([$2], [], [ax_cxx_compile_cxx11_required=true], | |
83 | [$2], [mandatory], [ax_cxx_compile_cxx11_required=true], | |
84 | [$2], [optional], [ax_cxx_compile_cxx11_required=false], | |
85 | [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX_11])]) | |
86 | AC_LANG_PUSH([C++])dnl | |
87 | ac_success=no | |
88 | AC_CACHE_CHECK(whether $CXX supports C++11 features by default, | |
89 | ax_cv_cxx_compile_cxx11, | |
90 | [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])], | |
91 | [ax_cv_cxx_compile_cxx11=yes], | |
92 | [ax_cv_cxx_compile_cxx11=no])]) | |
93 | if test x$ax_cv_cxx_compile_cxx11 = xyes; then | |
94 | ac_success=yes | |
95 | fi | |
96 | ||
97 | m4_if([$1], [noext], [], [dnl | |
98 | if test x$ac_success = xno; then | |
99 | for switch in -std=gnu++11 -std=gnu++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 | ||
117 | m4_if([$1], [ext], [], [dnl | |
118 | if test x$ac_success = xno; then | |
119 | for switch in -std=c++11 -std=c++0x; do | |
120 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch]) | |
121 | AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch, | |
122 | $cachevar, | |
123 | [ac_save_CXXFLAGS="$CXXFLAGS" | |
124 | CXXFLAGS="$CXXFLAGS $switch" | |
125 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])], | |
126 | [eval $cachevar=yes], | |
127 | [eval $cachevar=no]) | |
128 | CXXFLAGS="$ac_save_CXXFLAGS"]) | |
129 | if eval test x\$$cachevar = xyes; then | |
130 | CXXFLAGS="$CXXFLAGS $switch" | |
131 | ac_success=yes | |
132 | break | |
133 | fi | |
134 | done | |
135 | fi]) | |
136 | AC_LANG_POP([C++]) | |
137 | if test x$ax_cxx_compile_cxx11_required = xtrue; then | |
138 | if test x$ac_success = xno; then | |
139 | AC_MSG_ERROR([*** A compiler with support for C++11 language features is required.]) | |
140 | fi | |
141 | else | |
142 | if test x$ac_success = xno; then | |
143 | HAVE_CXX11=0 | |
144 | AC_MSG_NOTICE([No compiler with C++11 support was found]) | |
145 | else | |
146 | HAVE_CXX11=1 | |
147 | AC_DEFINE(HAVE_CXX11,1, | |
148 | [define if the compiler supports basic C++11 syntax]) | |
149 | fi | |
150 | ||
151 | AC_SUBST(HAVE_CXX11) | |
152 | fi | |
153 | ]) |