568 lines
14 KiB
568 lines
14 KiB
# =========================================================================== |
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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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m4_if([$4], [], [ax_cxx_compile_cxx$1_try_default=true], |
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[$4], [default], [ax_cxx_compile_cxx$1_try_default=true], |
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[$4], [nodefault], [ax_cxx_compile_cxx$1_try_default=false], |
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[m4_fatal([invalid fourth argument `$4' 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([$4], [nodefault], [], [dnl |
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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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#endif // __cplusplus >= 201402L |
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]])
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