134 lines
4.5 KiB
Plaintext
134 lines
4.5 KiB
Plaintext
# ============================================================================
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# http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html
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# ============================================================================
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#
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# SYNOPSIS
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#
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# AX_CXX_COMPILE_STDCXX_11([ext|noext],[mandatory|optional])
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#
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# DESCRIPTION
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#
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# Check for baseline language coverage in the compiler for the C++11
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# standard; if necessary, add switches to CXXFLAGS to enable support.
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#
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# The first argument, if specified, indicates whether you insist on an
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# extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
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# -std=c++11). If neither is specified, you get whatever works, with
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# preference for an extended mode.
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#
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# The second argument, if specified 'mandatory' or if left unspecified,
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# indicates that baseline C++11 support is required and that the macro
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# should error out if no mode with that support is found. If specified
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# 'optional', then configuration proceeds regardless, after defining
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# HAVE_CXX11 if and only if a supporting mode is found.
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#
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# LICENSE
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#
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# Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com>
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# Copyright (c) 2012 Zack Weinberg <zackw@panix.com>
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# Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu>
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#
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# Copying and distribution of this file, with or without modification, are
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# permitted in any medium without royalty provided the copyright notice
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# and this notice are preserved. This file is offered as-is, without any
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# warranty.
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#serial 3
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m4_define([_AX_CXX_COMPILE_STDCXX_11_testbody], [
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template <typename T>
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struct check
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{
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static_assert(sizeof(int) <= sizeof(T), "not big enough");
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};
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typedef check<check<bool>> right_angle_brackets;
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int a;
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decltype(a) b;
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typedef check<int> check_type;
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check_type c;
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check_type&& cr = static_cast<check_type&&>(c);
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auto d = a;
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])
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AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [dnl
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m4_if([$1], [], [],
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[$1], [ext], [],
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[$1], [noext], [],
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[m4_fatal([invalid argument `$1' to AX_CXX_COMPILE_STDCXX_11])])dnl
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m4_if([$2], [], [ax_cxx_compile_cxx11_required=true],
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[$2], [mandatory], [ax_cxx_compile_cxx11_required=true],
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[$2], [optional], [ax_cxx_compile_cxx11_required=false],
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[m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX_11])])dnl
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AC_LANG_PUSH([C++])dnl
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ac_success=no
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AC_CACHE_CHECK(whether $CXX supports C++11 features by default,
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ax_cv_cxx_compile_cxx11,
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[AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
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[ax_cv_cxx_compile_cxx11=yes],
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[ax_cv_cxx_compile_cxx11=no])])
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if test x$ax_cv_cxx_compile_cxx11 = xyes; then
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ac_success=yes
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fi
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m4_if([$1], [noext], [], [dnl
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if test x$ac_success = xno; then
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for switch in -std=gnu++11 -std=gnu++0x; do
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cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
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AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
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$cachevar,
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[ac_save_CXXFLAGS="$CXXFLAGS"
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CXXFLAGS="$CXXFLAGS $switch"
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AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
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[eval $cachevar=yes],
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[eval $cachevar=no])
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CXXFLAGS="$ac_save_CXXFLAGS"])
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if eval test x\$$cachevar = xyes; then
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CXXFLAGS="$CXXFLAGS $switch"
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ac_success=yes
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break
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fi
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done
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fi])
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m4_if([$1], [ext], [], [dnl
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if test x$ac_success = xno; then
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for switch in -std=c++11 -std=c++0x; do
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cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
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AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
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$cachevar,
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[ac_save_CXXFLAGS="$CXXFLAGS"
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CXXFLAGS="$CXXFLAGS $switch"
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AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
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[eval $cachevar=yes],
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[eval $cachevar=no])
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CXXFLAGS="$ac_save_CXXFLAGS"])
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if eval test x\$$cachevar = xyes; then
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CXXFLAGS="$CXXFLAGS $switch"
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ac_success=yes
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break
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fi
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done
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fi])
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AC_LANG_POP([C++])
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if test x$ax_cxx_compile_cxx11_required = xtrue; then
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if test x$ac_success = xno; then
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AC_MSG_ERROR([*** A compiler with support for C++11 language features is required.])
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fi
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else
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if test x$ac_success = xno; then
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HAVE_CXX11=0
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AC_MSG_NOTICE([No compiler with C++11 support was found])
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else
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HAVE_CXX11=1
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AC_DEFINE(HAVE_CXX11,1,
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[define if the compiler supports basic C++11 syntax])
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fi
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AC_SUBST(HAVE_CXX11)
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fi
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])
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