c07aaef6eb
* configure.ac: Call ax_cxx_compile_stdcxx * m4/ax_cxx_compile_stdcxx.m4 -- Depending on c++11 is intended to make the port away from Boost easier. The m4 macro was taken from the website mentioned in the License header of the file.
563 lines
14 KiB
Plaintext
563 lines
14 KiB
Plaintext
# ===========================================================================
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# http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.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(VERSION, [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 specified
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# version of the C++ standard. If necessary, add switches to CXX and
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# CXXCPP to enable support. VERSION may be '11' (for the C++11 standard)
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# or '14' (for the C++14 standard).
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#
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# The second 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 third argument, if specified 'mandatory' or if left unspecified,
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# indicates that baseline support for the specified C++ standard is
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# required and that the macro should error out if no mode with that
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# support is found. If specified 'optional', then configuration proceeds
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# regardless, after defining HAVE_CXX${VERSION} if and only if a
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# 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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# Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com>
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# Copyright (c) 2015 Paul Norman <penorman@mac.com>
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# Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu>
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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 4
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dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
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dnl (serial version number 13).
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AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
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m4_if([$1], [11], [],
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[$1], [14], [],
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[$1], [17], [m4_fatal([support for C++17 not yet implemented in AX_CXX_COMPILE_STDCXX])],
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[m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
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m4_if([$2], [], [],
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[$2], [ext], [],
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[$2], [noext], [],
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[m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl
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m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true],
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[$3], [mandatory], [ax_cxx_compile_cxx$1_required=true],
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[$3], [optional], [ax_cxx_compile_cxx$1_required=false],
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[m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])])
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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++$1 features by default,
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ax_cv_cxx_compile_cxx$1,
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[AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
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[ax_cv_cxx_compile_cxx$1=yes],
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[ax_cv_cxx_compile_cxx$1=no])])
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if test x$ax_cv_cxx_compile_cxx$1 = xyes; then
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ac_success=yes
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fi
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m4_if([$2], [noext], [], [dnl
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if test x$ac_success = xno; then
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for switch in -std=gnu++$1 -std=gnu++0x; do
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cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
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AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
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$cachevar,
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[ac_save_CXX="$CXX"
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CXX="$CXX $switch"
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AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
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[eval $cachevar=yes],
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[eval $cachevar=no])
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CXX="$ac_save_CXX"])
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if eval test x\$$cachevar = xyes; then
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CXX="$CXX $switch"
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if test -n "$CXXCPP" ; then
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CXXCPP="$CXXCPP $switch"
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fi
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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([$2], [ext], [], [dnl
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if test x$ac_success = xno; then
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dnl HP's aCC needs +std=c++11 according to:
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dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf
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dnl Cray's crayCC needs "-h std=c++11"
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for switch in -std=c++$1 -std=c++0x +std=c++$1 "-h std=c++$1"; do
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cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
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AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
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$cachevar,
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[ac_save_CXX="$CXX"
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CXX="$CXX $switch"
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AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
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[eval $cachevar=yes],
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[eval $cachevar=no])
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CXX="$ac_save_CXX"])
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if eval test x\$$cachevar = xyes; then
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CXX="$CXX $switch"
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if test -n "$CXXCPP" ; then
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CXXCPP="$CXXCPP $switch"
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fi
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ac_success=yes
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break
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fi
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done
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fi])
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AC_LANG_POP([C++])
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if test x$ax_cxx_compile_cxx$1_required = xtrue; then
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if test x$ac_success = xno; then
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AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.])
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fi
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fi
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if test x$ac_success = xno; then
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HAVE_CXX$1=0
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AC_MSG_NOTICE([No compiler with C++$1 support was found])
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else
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HAVE_CXX$1=1
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AC_DEFINE(HAVE_CXX$1,1,
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[define if the compiler supports basic C++$1 syntax])
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fi
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AC_SUBST(HAVE_CXX$1)
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])
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dnl Test body for checking C++11 support
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m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11],
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_AX_CXX_COMPILE_STDCXX_testbody_new_in_11
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)
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dnl Test body for checking C++14 support
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m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14],
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_AX_CXX_COMPILE_STDCXX_testbody_new_in_11
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_AX_CXX_COMPILE_STDCXX_testbody_new_in_14
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)
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dnl Tests for new features in C++11
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m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[
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// If the compiler admits that it is not ready for C++11, why torture it?
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// Hopefully, this will speed up the test.
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#ifndef __cplusplus
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#error "This is not a C++ compiler"
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#elif __cplusplus < 201103L
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#error "This is not a C++11 compiler"
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#else
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namespace cxx11
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{
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namespace test_static_assert
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{
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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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}
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namespace test_final_override
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{
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struct Base
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{
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virtual void f() {}
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};
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struct Derived : public Base
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{
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virtual void f() override {}
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};
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}
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namespace test_double_right_angle_brackets
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{
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template < typename T >
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struct check {};
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typedef check<void> single_type;
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typedef check<check<void>> double_type;
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typedef check<check<check<void>>> triple_type;
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typedef check<check<check<check<void>>>> quadruple_type;
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}
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namespace test_decltype
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{
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int
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f()
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{
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int a = 1;
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decltype(a) b = 2;
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return a + b;
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}
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}
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namespace test_type_deduction
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{
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template < typename T1, typename T2 >
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struct is_same
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{
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static const bool value = false;
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};
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template < typename T >
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struct is_same<T, T>
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{
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static const bool value = true;
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};
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template < typename T1, typename T2 >
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auto
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add(T1 a1, T2 a2) -> decltype(a1 + a2)
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{
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return a1 + a2;
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}
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int
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test(const int c, volatile int v)
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{
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static_assert(is_same<int, decltype(0)>::value == true, "");
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static_assert(is_same<int, decltype(c)>::value == false, "");
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static_assert(is_same<int, decltype(v)>::value == false, "");
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auto ac = c;
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auto av = v;
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auto sumi = ac + av + 'x';
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auto sumf = ac + av + 1.0;
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static_assert(is_same<int, decltype(ac)>::value == true, "");
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static_assert(is_same<int, decltype(av)>::value == true, "");
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static_assert(is_same<int, decltype(sumi)>::value == true, "");
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static_assert(is_same<int, decltype(sumf)>::value == false, "");
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static_assert(is_same<int, decltype(add(c, v))>::value == true, "");
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return (sumf > 0.0) ? sumi : add(c, v);
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}
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}
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namespace test_noexcept
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{
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int f() { return 0; }
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int g() noexcept { return 0; }
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static_assert(noexcept(f()) == false, "");
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static_assert(noexcept(g()) == true, "");
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}
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namespace test_constexpr
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{
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template < typename CharT >
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unsigned long constexpr
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strlen_c_r(const CharT *const s, const unsigned long acc) noexcept
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{
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return *s ? strlen_c_r(s + 1, acc + 1) : acc;
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}
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template < typename CharT >
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unsigned long constexpr
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strlen_c(const CharT *const s) noexcept
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{
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return strlen_c_r(s, 0UL);
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}
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static_assert(strlen_c("") == 0UL, "");
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static_assert(strlen_c("1") == 1UL, "");
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static_assert(strlen_c("example") == 7UL, "");
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static_assert(strlen_c("another\0example") == 7UL, "");
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}
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namespace test_rvalue_references
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{
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template < int N >
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struct answer
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{
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static constexpr int value = N;
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};
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answer<1> f(int&) { return answer<1>(); }
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answer<2> f(const int&) { return answer<2>(); }
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answer<3> f(int&&) { return answer<3>(); }
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void
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test()
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{
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int i = 0;
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const int c = 0;
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static_assert(decltype(f(i))::value == 1, "");
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static_assert(decltype(f(c))::value == 2, "");
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static_assert(decltype(f(0))::value == 3, "");
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}
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}
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namespace test_uniform_initialization
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{
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struct test
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{
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static const int zero {};
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static const int one {1};
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};
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static_assert(test::zero == 0, "");
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static_assert(test::one == 1, "");
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}
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namespace test_lambdas
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{
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void
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test1()
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{
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auto lambda1 = [](){};
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auto lambda2 = lambda1;
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lambda1();
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lambda2();
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}
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int
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test2()
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{
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auto a = [](int i, int j){ return i + j; }(1, 2);
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auto b = []() -> int { return '0'; }();
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auto c = [=](){ return a + b; }();
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auto d = [&](){ return c; }();
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auto e = [a, &b](int x) mutable {
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const auto identity = [](int y){ return y; };
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for (auto i = 0; i < a; ++i)
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a += b--;
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return x + identity(a + b);
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}(0);
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return a + b + c + d + e;
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}
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int
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test3()
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{
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const auto nullary = [](){ return 0; };
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const auto unary = [](int x){ return x; };
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using nullary_t = decltype(nullary);
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using unary_t = decltype(unary);
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const auto higher1st = [](nullary_t f){ return f(); };
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const auto higher2nd = [unary](nullary_t f1){
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return [unary, f1](unary_t f2){ return f2(unary(f1())); };
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};
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return higher1st(nullary) + higher2nd(nullary)(unary);
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}
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}
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namespace test_variadic_templates
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{
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template <int...>
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struct sum;
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template <int N0, int... N1toN>
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struct sum<N0, N1toN...>
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{
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static constexpr auto value = N0 + sum<N1toN...>::value;
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};
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template <>
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struct sum<>
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{
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static constexpr auto value = 0;
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};
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static_assert(sum<>::value == 0, "");
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static_assert(sum<1>::value == 1, "");
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static_assert(sum<23>::value == 23, "");
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static_assert(sum<1, 2>::value == 3, "");
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static_assert(sum<5, 5, 11>::value == 21, "");
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static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, "");
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}
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// http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
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// Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function
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// because of this.
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namespace test_template_alias_sfinae
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{
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struct foo {};
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template<typename T>
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using member = typename T::member_type;
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template<typename T>
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void func(...) {}
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template<typename T>
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void func(member<T>*) {}
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void test();
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void test() { func<foo>(0); }
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}
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} // namespace cxx11
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#endif // __cplusplus >= 201103L
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]])
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dnl Tests for new features in C++14
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m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[
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// If the compiler admits that it is not ready for C++14, why torture it?
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// Hopefully, this will speed up the test.
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#ifndef __cplusplus
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#error "This is not a C++ compiler"
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#elif __cplusplus < 201402L
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#error "This is not a C++14 compiler"
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#else
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namespace cxx14
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{
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namespace test_polymorphic_lambdas
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{
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int
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test()
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{
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const auto lambda = [](auto&&... args){
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const auto istiny = [](auto x){
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return (sizeof(x) == 1UL) ? 1 : 0;
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};
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const int aretiny[] = { istiny(args)... };
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return aretiny[0];
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};
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return lambda(1, 1L, 1.0f, '1');
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}
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}
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namespace test_binary_literals
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{
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constexpr auto ivii = 0b0000000000101010;
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static_assert(ivii == 42, "wrong value");
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}
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namespace test_generalized_constexpr
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{
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template < typename CharT >
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constexpr unsigned long
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strlen_c(const CharT *const s) noexcept
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{
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auto length = 0UL;
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for (auto p = s; *p; ++p)
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++length;
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return length;
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}
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static_assert(strlen_c("") == 0UL, "");
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static_assert(strlen_c("x") == 1UL, "");
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static_assert(strlen_c("test") == 4UL, "");
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static_assert(strlen_c("another\0test") == 7UL, "");
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}
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namespace test_lambda_init_capture
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{
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int
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test()
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{
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auto x = 0;
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const auto lambda1 = [a = x](int b){ return a + b; };
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const auto lambda2 = [a = lambda1(x)](){ return a; };
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return lambda2();
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}
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}
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namespace test_digit_seperators
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{
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constexpr auto ten_million = 100'000'000;
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static_assert(ten_million == 100000000, "");
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}
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namespace test_return_type_deduction
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{
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auto f(int& x) { return x; }
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decltype(auto) g(int& x) { return x; }
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template < typename T1, typename T2 >
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struct is_same
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{
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static constexpr auto value = false;
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};
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template < typename T >
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struct is_same<T, T>
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{
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static constexpr auto value = true;
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};
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int
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test()
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{
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auto x = 0;
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static_assert(is_same<int, decltype(f(x))>::value, "");
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static_assert(is_same<int&, decltype(g(x))>::value, "");
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return x;
|
|
}
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|
|
|
}
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|
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} // namespace cxx14
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|
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#endif // __cplusplus >= 201402L
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|
|
|
]])
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