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951 lines
19 KiB
951 lines
19 KiB
# =========================================================================== |
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# https://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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# Copyright (c) 2016, 2018 Krzesimir Nowak <qdlacz@gmail.com> |
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# Copyright (c) 2019 Enji Cooper <yaneurabeya@gmail.com> |
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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 11 |
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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], [ax_cxx_compile_alternatives="11 0x"], |
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[$1], [14], [ax_cxx_compile_alternatives="14 1y"], |
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[$1], [17], [ax_cxx_compile_alternatives="17 1z"], |
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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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m4_if([$2], [noext], [], [dnl |
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if test x$ac_success = xno; then |
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for alternative in ${ax_cxx_compile_alternatives}; do |
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switch="-std=gnu++${alternative}" |
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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 alternative in ${ax_cxx_compile_alternatives}; do |
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for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${alternative}"; 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 $switch" |
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fi |
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ac_success=yes |
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break |
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fi |
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done |
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if test x$ac_success = xyes; then |
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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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m4_define([_AX_CXX_COMPILE_STDCXX_testbody_17], |
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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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_AX_CXX_COMPILE_STDCXX_testbody_new_in_17 |
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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 ~Base() {} |
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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 ~Derived() override {} |
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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_separators |
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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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#endif // __cplusplus >= 201402L |
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]]) |
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dnl Tests for new features in C++17 |
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m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_17], [[ |
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// If the compiler admits that it is not ready for C++17, 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 < 201703L |
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#error "This is not a C++17 compiler" |
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#else |
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#include <initializer_list> |
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#include <utility> |
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#include <type_traits> |
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namespace cxx17 |
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{ |
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namespace test_constexpr_lambdas |
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{ |
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constexpr int foo = [](){return 42;}(); |
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} |
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namespace test::nested_namespace::definitions |
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{ |
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} |
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namespace test_fold_expression |
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{ |
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template<typename... Args> |
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int multiply(Args... args) |
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{ |
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return (args * ... * 1); |
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} |
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template<typename... Args> |
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bool all(Args... args) |
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{ |
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return (args && ...); |
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} |
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|
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} |
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namespace test_extended_static_assert |
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{ |
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static_assert (true); |
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} |
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namespace test_auto_brace_init_list |
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{ |
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auto foo = {5}; |
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auto bar {5}; |
|
|
|
static_assert(std::is_same<std::initializer_list<int>, decltype(foo)>::value); |
|
static_assert(std::is_same<int, decltype(bar)>::value); |
|
} |
|
|
|
namespace test_typename_in_template_template_parameter |
|
{ |
|
|
|
template<template<typename> typename X> struct D; |
|
|
|
} |
|
|
|
namespace test_fallthrough_nodiscard_maybe_unused_attributes |
|
{ |
|
|
|
int f1() |
|
{ |
|
return 42; |
|
} |
|
|
|
[[nodiscard]] int f2() |
|
{ |
|
[[maybe_unused]] auto unused = f1(); |
|
|
|
switch (f1()) |
|
{ |
|
case 17: |
|
f1(); |
|
[[fallthrough]]; |
|
case 42: |
|
f1(); |
|
} |
|
return f1(); |
|
} |
|
|
|
} |
|
|
|
namespace test_extended_aggregate_initialization |
|
{ |
|
|
|
struct base1 |
|
{ |
|
int b1, b2 = 42; |
|
}; |
|
|
|
struct base2 |
|
{ |
|
base2() { |
|
b3 = 42; |
|
} |
|
int b3; |
|
}; |
|
|
|
struct derived : base1, base2 |
|
{ |
|
int d; |
|
}; |
|
|
|
derived d1 {{1, 2}, {}, 4}; // full initialization |
|
derived d2 {{}, {}, 4}; // value-initialized bases |
|
|
|
} |
|
|
|
namespace test_general_range_based_for_loop |
|
{ |
|
|
|
struct iter |
|
{ |
|
int i; |
|
|
|
int& operator* () |
|
{ |
|
return i; |
|
} |
|
|
|
const int& operator* () const |
|
{ |
|
return i; |
|
} |
|
|
|
iter& operator++() |
|
{ |
|
++i; |
|
return *this; |
|
} |
|
}; |
|
|
|
struct sentinel |
|
{ |
|
int i; |
|
}; |
|
|
|
bool operator== (const iter& i, const sentinel& s) |
|
{ |
|
return i.i == s.i; |
|
} |
|
|
|
bool operator!= (const iter& i, const sentinel& s) |
|
{ |
|
return !(i == s); |
|
} |
|
|
|
struct range |
|
{ |
|
iter begin() const |
|
{ |
|
return {0}; |
|
} |
|
|
|
sentinel end() const |
|
{ |
|
return {5}; |
|
} |
|
}; |
|
|
|
void f() |
|
{ |
|
range r {}; |
|
|
|
for (auto i : r) |
|
{ |
|
[[maybe_unused]] auto v = i; |
|
} |
|
} |
|
|
|
} |
|
|
|
namespace test_lambda_capture_asterisk_this_by_value |
|
{ |
|
|
|
struct t |
|
{ |
|
int i; |
|
int foo() |
|
{ |
|
return [*this]() |
|
{ |
|
return i; |
|
}(); |
|
} |
|
}; |
|
|
|
} |
|
|
|
namespace test_enum_class_construction |
|
{ |
|
|
|
enum class byte : unsigned char |
|
{}; |
|
|
|
byte foo {42}; |
|
|
|
} |
|
|
|
namespace test_constexpr_if |
|
{ |
|
|
|
template <bool cond> |
|
int f () |
|
{ |
|
if constexpr(cond) |
|
{ |
|
return 13; |
|
} |
|
else |
|
{ |
|
return 42; |
|
} |
|
} |
|
|
|
} |
|
|
|
namespace test_selection_statement_with_initializer |
|
{ |
|
|
|
int f() |
|
{ |
|
return 13; |
|
} |
|
|
|
int f2() |
|
{ |
|
if (auto i = f(); i > 0) |
|
{ |
|
return 3; |
|
} |
|
|
|
switch (auto i = f(); i + 4) |
|
{ |
|
case 17: |
|
return 2; |
|
|
|
default: |
|
return 1; |
|
} |
|
} |
|
|
|
} |
|
|
|
namespace test_template_argument_deduction_for_class_templates |
|
{ |
|
|
|
template <typename T1, typename T2> |
|
struct pair |
|
{ |
|
pair (T1 p1, T2 p2) |
|
: m1 {p1}, |
|
m2 {p2} |
|
{} |
|
|
|
T1 m1; |
|
T2 m2; |
|
}; |
|
|
|
void f() |
|
{ |
|
[[maybe_unused]] auto p = pair{13, 42u}; |
|
} |
|
|
|
} |
|
|
|
namespace test_non_type_auto_template_parameters |
|
{ |
|
|
|
template <auto n> |
|
struct B |
|
{}; |
|
|
|
B<5> b1; |
|
B<'a'> b2; |
|
|
|
} |
|
|
|
namespace test_structured_bindings |
|
{ |
|
|
|
int arr[2] = { 1, 2 }; |
|
std::pair<int, int> pr = { 1, 2 }; |
|
|
|
auto f1() -> int(&)[2] |
|
{ |
|
return arr; |
|
} |
|
|
|
auto f2() -> std::pair<int, int>& |
|
{ |
|
return pr; |
|
} |
|
|
|
struct S |
|
{ |
|
int x1 : 2; |
|
volatile double y1; |
|
}; |
|
|
|
S f3() |
|
{ |
|
return {}; |
|
} |
|
|
|
auto [ x1, y1 ] = f1(); |
|
auto& [ xr1, yr1 ] = f1(); |
|
auto [ x2, y2 ] = f2(); |
|
auto& [ xr2, yr2 ] = f2(); |
|
const auto [ x3, y3 ] = f3(); |
|
|
|
} |
|
|
|
namespace test_exception_spec_type_system |
|
{ |
|
|
|
struct Good {}; |
|
struct Bad {}; |
|
|
|
void g1() noexcept; |
|
void g2(); |
|
|
|
template<typename T> |
|
Bad |
|
f(T*, T*); |
|
|
|
template<typename T1, typename T2> |
|
Good |
|
f(T1*, T2*); |
|
|
|
static_assert (std::is_same_v<Good, decltype(f(g1, g2))>); |
|
|
|
} |
|
|
|
namespace test_inline_variables |
|
{ |
|
|
|
template<class T> void f(T) |
|
{} |
|
|
|
template<class T> inline T g(T) |
|
{ |
|
return T{}; |
|
} |
|
|
|
template<> inline void f<>(int) |
|
{} |
|
|
|
template<> int g<>(int) |
|
{ |
|
return 5; |
|
} |
|
|
|
} |
|
|
|
} // namespace cxx17 |
|
|
|
#endif // __cplusplus < 201703L |
|
|
|
]])
|
|
|