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authorDaniel Baumann <daniel.baumann@progress-linux.org>2023-05-08 16:27:08 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2023-05-08 16:27:08 +0000
commit81581f9719bc56f01d5aa08952671d65fda9867a (patch)
tree0f5c6b6138bf169c23c9d24b1fc0a3521385cb18 /build/m4
parentReleasing debian version 1.38.1-1. (diff)
downloadnetdata-81581f9719bc56f01d5aa08952671d65fda9867a.tar.xz
netdata-81581f9719bc56f01d5aa08952671d65fda9867a.zip
Merging upstream version 1.39.0.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'build/m4')
-rw-r--r--build/m4/ax_compiler_vendor.m4119
-rw-r--r--build/m4/ax_cxx_compile_stdcxx.m41018
2 files changed, 1137 insertions, 0 deletions
diff --git a/build/m4/ax_compiler_vendor.m4 b/build/m4/ax_compiler_vendor.m4
new file mode 100644
index 000000000..039f99d2b
--- /dev/null
+++ b/build/m4/ax_compiler_vendor.m4
@@ -0,0 +1,119 @@
+# ===========================================================================
+# https://www.gnu.org/software/autoconf-archive/ax_compiler_vendor.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+# AX_COMPILER_VENDOR
+#
+# DESCRIPTION
+#
+# Determine the vendor of the C, C++ or Fortran compiler. The vendor is
+# returned in the cache variable $ax_cv_c_compiler_vendor for C,
+# $ax_cv_cxx_compiler_vendor for C++ or $ax_cv_fc_compiler_vendor for
+# (modern) Fortran. The value is one of "intel", "ibm", "pathscale",
+# "clang" (LLVM), "cray", "fujitsu", "sdcc", "sx", "nvhpc" (NVIDIA HPC
+# Compiler), "portland" (PGI), "gnu" (GCC), "sun" (Oracle Developer
+# Studio), "hp", "dec", "borland", "comeau", "kai", "lcc", "sgi",
+# "microsoft", "metrowerks", "watcom", "tcc" (Tiny CC) or "unknown" (if
+# the compiler cannot be determined).
+#
+# To check for a Fortran compiler, you must first call AC_FC_PP_SRCEXT
+# with an appropriate preprocessor-enabled extension. For example:
+#
+# AC_LANG_PUSH([Fortran])
+# AC_PROG_FC
+# AC_FC_PP_SRCEXT([F])
+# AX_COMPILER_VENDOR
+# AC_LANG_POP([Fortran])
+#
+# LICENSE
+#
+# Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
+# Copyright (c) 2008 Matteo Frigo
+# Copyright (c) 2018-19 John Zaitseff <J.Zaitseff@zap.org.au>
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation, either version 3 of the License, or (at your
+# option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+# Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+# As a special exception, the respective Autoconf Macro's copyright owner
+# gives unlimited permission to copy, distribute and modify the configure
+# scripts that are the output of Autoconf when processing the Macro. You
+# need not follow the terms of the GNU General Public License when using
+# or distributing such scripts, even though portions of the text of the
+# Macro appear in them. The GNU General Public License (GPL) does govern
+# all other use of the material that constitutes the Autoconf Macro.
+#
+# This special exception to the GPL applies to versions of the Autoconf
+# Macro released by the Autoconf Archive. When you make and distribute a
+# modified version of the Autoconf Macro, you may extend this special
+# exception to the GPL to apply to your modified version as well.
+
+#serial 32
+
+AC_DEFUN([AX_COMPILER_VENDOR], [dnl
+ AC_CACHE_CHECK([for _AC_LANG compiler vendor], ax_cv_[]_AC_LANG_ABBREV[]_compiler_vendor, [dnl
+ dnl If you modify this list of vendors, please add similar support
+ dnl to ax_compiler_version.m4 if at all possible.
+ dnl
+ dnl Note: Do NOT check for GCC first since some other compilers
+ dnl define __GNUC__ to remain compatible with it. Compilers that
+ dnl are very slow to start (such as Intel) are listed first.
+
+ vendors="
+ intel: __ICC,__ECC,__INTEL_COMPILER
+ ibm: __xlc__,__xlC__,__IBMC__,__IBMCPP__,__ibmxl__
+ pathscale: __PATHCC__,__PATHSCALE__
+ clang: __clang__
+ cray: _CRAYC
+ fujitsu: __FUJITSU
+ sdcc: SDCC,__SDCC
+ sx: _SX
+ nvhpc: __NVCOMPILER
+ portland: __PGI
+ gnu: __GNUC__
+ sun: __SUNPRO_C,__SUNPRO_CC,__SUNPRO_F90,__SUNPRO_F95
+ hp: __HP_cc,__HP_aCC
+ dec: __DECC,__DECCXX,__DECC_VER,__DECCXX_VER
+ borland: __BORLANDC__,__CODEGEARC__,__TURBOC__
+ comeau: __COMO__
+ kai: __KCC
+ lcc: __LCC__
+ sgi: __sgi,sgi
+ microsoft: _MSC_VER
+ metrowerks: __MWERKS__
+ watcom: __WATCOMC__
+ tcc: __TINYC__
+ unknown: UNKNOWN
+ "
+ for ventest in $vendors; do
+ case $ventest in
+ *:)
+ vendor=$ventest
+ continue
+ ;;
+ *)
+ vencpp="defined("`echo $ventest | sed 's/,/) || defined(/g'`")"
+ ;;
+ esac
+
+ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [[
+#if !($vencpp)
+ thisisanerror;
+#endif
+ ]])], [break])
+ done
+
+ ax_cv_[]_AC_LANG_ABBREV[]_compiler_vendor=`echo $vendor | cut -d: -f1`
+ ])
+])dnl
diff --git a/build/m4/ax_cxx_compile_stdcxx.m4 b/build/m4/ax_cxx_compile_stdcxx.m4
new file mode 100644
index 000000000..8edf5152e
--- /dev/null
+++ b/build/m4/ax_cxx_compile_stdcxx.m4
@@ -0,0 +1,1018 @@
+# ===========================================================================
+# https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+# AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional])
+#
+# DESCRIPTION
+#
+# Check for baseline language coverage in the compiler for the specified
+# version of the C++ standard. If necessary, add switches to CXX and
+# CXXCPP to enable support. VERSION may be '11', '14', '17', or '20' for
+# the respective C++ standard version.
+#
+# The second argument, if specified, indicates whether you insist on an
+# extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
+# -std=c++11). If neither is specified, you get whatever works, with
+# preference for no added switch, and then for an extended mode.
+#
+# The third argument, if specified 'mandatory' or if left unspecified,
+# indicates that baseline support for the specified C++ standard is
+# required and that the macro should error out if no mode with that
+# support is found. If specified 'optional', then configuration proceeds
+# regardless, after defining HAVE_CXX${VERSION} if and only if a
+# supporting mode is found.
+#
+# LICENSE
+#
+# Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com>
+# Copyright (c) 2012 Zack Weinberg <zackw@panix.com>
+# Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu>
+# Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com>
+# Copyright (c) 2015 Paul Norman <penorman@mac.com>
+# Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu>
+# Copyright (c) 2016, 2018 Krzesimir Nowak <qdlacz@gmail.com>
+# Copyright (c) 2019 Enji Cooper <yaneurabeya@gmail.com>
+# Copyright (c) 2020 Jason Merrill <jason@redhat.com>
+# Copyright (c) 2021 Jörn Heusipp <osmanx@problemloesungsmaschine.de>
+#
+# Copying and distribution of this file, with or without modification, are
+# permitted in any medium without royalty provided the copyright notice
+# and this notice are preserved. This file is offered as-is, without any
+# warranty.
+
+#serial 18
+
+dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro
+dnl (serial version number 13).
+
+AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl
+ m4_if([$1], [11], [ax_cxx_compile_alternatives="11 0x"],
+ [$1], [14], [ax_cxx_compile_alternatives="14 1y"],
+ [$1], [17], [ax_cxx_compile_alternatives="17 1z"],
+ [$1], [20], [ax_cxx_compile_alternatives="20"],
+ [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl
+ m4_if([$2], [], [],
+ [$2], [ext], [],
+ [$2], [noext], [],
+ [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl
+ m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true],
+ [$3], [mandatory], [ax_cxx_compile_cxx$1_required=true],
+ [$3], [optional], [ax_cxx_compile_cxx$1_required=false],
+ [m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])])
+ AC_LANG_PUSH([C++])dnl
+ ac_success=no
+
+ m4_if([$2], [], [dnl
+ AC_CACHE_CHECK(whether $CXX supports C++$1 features by default,
+ ax_cv_cxx_compile_cxx$1,
+ [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+ [ax_cv_cxx_compile_cxx$1=yes],
+ [ax_cv_cxx_compile_cxx$1=no])])
+ if test x$ax_cv_cxx_compile_cxx$1 = xyes; then
+ ac_success=yes
+ fi])
+
+ m4_if([$2], [noext], [], [dnl
+ if test x$ac_success = xno; then
+ for alternative in ${ax_cxx_compile_alternatives}; do
+ switch="-std=gnu++${alternative}"
+ cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
+ AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
+ $cachevar,
+ [ac_save_CXX="$CXX"
+ CXX="$CXX $switch"
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+ [eval $cachevar=yes],
+ [eval $cachevar=no])
+ CXX="$ac_save_CXX"])
+ if eval test x\$$cachevar = xyes; then
+ CXX="$CXX $switch"
+ if test -n "$CXXCPP" ; then
+ CXXCPP="$CXXCPP $switch"
+ fi
+ ac_success=yes
+ break
+ fi
+ done
+ fi])
+
+ m4_if([$2], [ext], [], [dnl
+ if test x$ac_success = xno; then
+ dnl HP's aCC needs +std=c++11 according to:
+ dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf
+ dnl Cray's crayCC needs "-h std=c++11"
+ dnl MSVC needs -std:c++NN for C++17 and later (default is C++14)
+ for alternative in ${ax_cxx_compile_alternatives}; do
+ for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${alternative}" MSVC; do
+ if test x"$switch" = xMSVC; then
+ dnl AS_TR_SH maps both `:` and `=` to `_` so -std:c++17 would collide
+ dnl with -std=c++17. We suffix the cache variable name with _MSVC to
+ dnl avoid this.
+ switch=-std:c++${alternative}
+ cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_${switch}_MSVC])
+ else
+ cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch])
+ fi
+ AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch,
+ $cachevar,
+ [ac_save_CXX="$CXX"
+ CXX="$CXX $switch"
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])],
+ [eval $cachevar=yes],
+ [eval $cachevar=no])
+ CXX="$ac_save_CXX"])
+ if eval test x\$$cachevar = xyes; then
+ CXX="$CXX $switch"
+ if test -n "$CXXCPP" ; then
+ CXXCPP="$CXXCPP $switch"
+ fi
+ ac_success=yes
+ break
+ fi
+ done
+ if test x$ac_success = xyes; then
+ break
+ fi
+ done
+ fi])
+ AC_LANG_POP([C++])
+ if test x$ax_cxx_compile_cxx$1_required = xtrue; then
+ if test x$ac_success = xno; then
+ AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.])
+ fi
+ fi
+ if test x$ac_success = xno; then
+ HAVE_CXX$1=0
+ AC_MSG_NOTICE([No compiler with C++$1 support was found])
+ else
+ HAVE_CXX$1=1
+ AC_DEFINE(HAVE_CXX$1,1,
+ [define if the compiler supports basic C++$1 syntax])
+ fi
+ AC_SUBST(HAVE_CXX$1)
+])
+
+
+dnl Test body for checking C++11 support
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11],
+ _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
+)
+
+dnl Test body for checking C++14 support
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14],
+ _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
+ _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
+)
+
+dnl Test body for checking C++17 support
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_17],
+ _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
+ _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
+ _AX_CXX_COMPILE_STDCXX_testbody_new_in_17
+)
+
+dnl Test body for checking C++20 support
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_20],
+ _AX_CXX_COMPILE_STDCXX_testbody_new_in_11
+ _AX_CXX_COMPILE_STDCXX_testbody_new_in_14
+ _AX_CXX_COMPILE_STDCXX_testbody_new_in_17
+ _AX_CXX_COMPILE_STDCXX_testbody_new_in_20
+)
+
+
+dnl Tests for new features in C++11
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[
+
+// If the compiler admits that it is not ready for C++11, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+// MSVC always sets __cplusplus to 199711L in older versions; newer versions
+// only set it correctly if /Zc:__cplusplus is specified as well as a
+// /std:c++NN switch:
+// https://devblogs.microsoft.com/cppblog/msvc-now-correctly-reports-__cplusplus/
+#elif __cplusplus < 201103L && !defined _MSC_VER
+
+#error "This is not a C++11 compiler"
+
+#else
+
+namespace cxx11
+{
+
+ namespace test_static_assert
+ {
+
+ template <typename T>
+ struct check
+ {
+ static_assert(sizeof(int) <= sizeof(T), "not big enough");
+ };
+
+ }
+
+ namespace test_final_override
+ {
+
+ struct Base
+ {
+ virtual ~Base() {}
+ virtual void f() {}
+ };
+
+ struct Derived : public Base
+ {
+ virtual ~Derived() override {}
+ virtual void f() override {}
+ };
+
+ }
+
+ namespace test_double_right_angle_brackets
+ {
+
+ template < typename T >
+ struct check {};
+
+ typedef check<void> single_type;
+ typedef check<check<void>> double_type;
+ typedef check<check<check<void>>> triple_type;
+ typedef check<check<check<check<void>>>> quadruple_type;
+
+ }
+
+ namespace test_decltype
+ {
+
+ int
+ f()
+ {
+ int a = 1;
+ decltype(a) b = 2;
+ return a + b;
+ }
+
+ }
+
+ namespace test_type_deduction
+ {
+
+ template < typename T1, typename T2 >
+ struct is_same
+ {
+ static const bool value = false;
+ };
+
+ template < typename T >
+ struct is_same<T, T>
+ {
+ static const bool value = true;
+ };
+
+ template < typename T1, typename T2 >
+ auto
+ add(T1 a1, T2 a2) -> decltype(a1 + a2)
+ {
+ return a1 + a2;
+ }
+
+ int
+ test(const int c, volatile int v)
+ {
+ static_assert(is_same<int, decltype(0)>::value == true, "");
+ static_assert(is_same<int, decltype(c)>::value == false, "");
+ static_assert(is_same<int, decltype(v)>::value == false, "");
+ auto ac = c;
+ auto av = v;
+ auto sumi = ac + av + 'x';
+ auto sumf = ac + av + 1.0;
+ static_assert(is_same<int, decltype(ac)>::value == true, "");
+ static_assert(is_same<int, decltype(av)>::value == true, "");
+ static_assert(is_same<int, decltype(sumi)>::value == true, "");
+ static_assert(is_same<int, decltype(sumf)>::value == false, "");
+ static_assert(is_same<int, decltype(add(c, v))>::value == true, "");
+ return (sumf > 0.0) ? sumi : add(c, v);
+ }
+
+ }
+
+ namespace test_noexcept
+ {
+
+ int f() { return 0; }
+ int g() noexcept { return 0; }
+
+ static_assert(noexcept(f()) == false, "");
+ static_assert(noexcept(g()) == true, "");
+
+ }
+
+ namespace test_constexpr
+ {
+
+ template < typename CharT >
+ unsigned long constexpr
+ strlen_c_r(const CharT *const s, const unsigned long acc) noexcept
+ {
+ return *s ? strlen_c_r(s + 1, acc + 1) : acc;
+ }
+
+ template < typename CharT >
+ unsigned long constexpr
+ strlen_c(const CharT *const s) noexcept
+ {
+ return strlen_c_r(s, 0UL);
+ }
+
+ static_assert(strlen_c("") == 0UL, "");
+ static_assert(strlen_c("1") == 1UL, "");
+ static_assert(strlen_c("example") == 7UL, "");
+ static_assert(strlen_c("another\0example") == 7UL, "");
+
+ }
+
+ namespace test_rvalue_references
+ {
+
+ template < int N >
+ struct answer
+ {
+ static constexpr int value = N;
+ };
+
+ answer<1> f(int&) { return answer<1>(); }
+ answer<2> f(const int&) { return answer<2>(); }
+ answer<3> f(int&&) { return answer<3>(); }
+
+ void
+ test()
+ {
+ int i = 0;
+ const int c = 0;
+ static_assert(decltype(f(i))::value == 1, "");
+ static_assert(decltype(f(c))::value == 2, "");
+ static_assert(decltype(f(0))::value == 3, "");
+ }
+
+ }
+
+ namespace test_uniform_initialization
+ {
+
+ struct test
+ {
+ static const int zero {};
+ static const int one {1};
+ };
+
+ static_assert(test::zero == 0, "");
+ static_assert(test::one == 1, "");
+
+ }
+
+ namespace test_lambdas
+ {
+
+ void
+ test1()
+ {
+ auto lambda1 = [](){};
+ auto lambda2 = lambda1;
+ lambda1();
+ lambda2();
+ }
+
+ int
+ test2()
+ {
+ auto a = [](int i, int j){ return i + j; }(1, 2);
+ auto b = []() -> int { return '0'; }();
+ auto c = [=](){ return a + b; }();
+ auto d = [&](){ return c; }();
+ auto e = [a, &b](int x) mutable {
+ const auto identity = [](int y){ return y; };
+ for (auto i = 0; i < a; ++i)
+ a += b--;
+ return x + identity(a + b);
+ }(0);
+ return a + b + c + d + e;
+ }
+
+ int
+ test3()
+ {
+ const auto nullary = [](){ return 0; };
+ const auto unary = [](int x){ return x; };
+ using nullary_t = decltype(nullary);
+ using unary_t = decltype(unary);
+ const auto higher1st = [](nullary_t f){ return f(); };
+ const auto higher2nd = [unary](nullary_t f1){
+ return [unary, f1](unary_t f2){ return f2(unary(f1())); };
+ };
+ return higher1st(nullary) + higher2nd(nullary)(unary);
+ }
+
+ }
+
+ namespace test_variadic_templates
+ {
+
+ template <int...>
+ struct sum;
+
+ template <int N0, int... N1toN>
+ struct sum<N0, N1toN...>
+ {
+ static constexpr auto value = N0 + sum<N1toN...>::value;
+ };
+
+ template <>
+ struct sum<>
+ {
+ static constexpr auto value = 0;
+ };
+
+ static_assert(sum<>::value == 0, "");
+ static_assert(sum<1>::value == 1, "");
+ static_assert(sum<23>::value == 23, "");
+ static_assert(sum<1, 2>::value == 3, "");
+ static_assert(sum<5, 5, 11>::value == 21, "");
+ static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, "");
+
+ }
+
+ // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
+ // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function
+ // because of this.
+ namespace test_template_alias_sfinae
+ {
+
+ struct foo {};
+
+ template<typename T>
+ using member = typename T::member_type;
+
+ template<typename T>
+ void func(...) {}
+
+ template<typename T>
+ void func(member<T>*) {}
+
+ void test();
+
+ void test() { func<foo>(0); }
+
+ }
+
+} // namespace cxx11
+
+#endif // __cplusplus >= 201103L
+
+]])
+
+
+dnl Tests for new features in C++14
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[
+
+// If the compiler admits that it is not ready for C++14, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201402L && !defined _MSC_VER
+
+#error "This is not a C++14 compiler"
+
+#else
+
+namespace cxx14
+{
+
+ namespace test_polymorphic_lambdas
+ {
+
+ int
+ test()
+ {
+ const auto lambda = [](auto&&... args){
+ const auto istiny = [](auto x){
+ return (sizeof(x) == 1UL) ? 1 : 0;
+ };
+ const int aretiny[] = { istiny(args)... };
+ return aretiny[0];
+ };
+ return lambda(1, 1L, 1.0f, '1');
+ }
+
+ }
+
+ namespace test_binary_literals
+ {
+
+ constexpr auto ivii = 0b0000000000101010;
+ static_assert(ivii == 42, "wrong value");
+
+ }
+
+ namespace test_generalized_constexpr
+ {
+
+ template < typename CharT >
+ constexpr unsigned long
+ strlen_c(const CharT *const s) noexcept
+ {
+ auto length = 0UL;
+ for (auto p = s; *p; ++p)
+ ++length;
+ return length;
+ }
+
+ static_assert(strlen_c("") == 0UL, "");
+ static_assert(strlen_c("x") == 1UL, "");
+ static_assert(strlen_c("test") == 4UL, "");
+ static_assert(strlen_c("another\0test") == 7UL, "");
+
+ }
+
+ namespace test_lambda_init_capture
+ {
+
+ int
+ test()
+ {
+ auto x = 0;
+ const auto lambda1 = [a = x](int b){ return a + b; };
+ const auto lambda2 = [a = lambda1(x)](){ return a; };
+ return lambda2();
+ }
+
+ }
+
+ namespace test_digit_separators
+ {
+
+ constexpr auto ten_million = 100'000'000;
+ static_assert(ten_million == 100000000, "");
+
+ }
+
+ namespace test_return_type_deduction
+ {
+
+ auto f(int& x) { return x; }
+ decltype(auto) g(int& x) { return x; }
+
+ template < typename T1, typename T2 >
+ struct is_same
+ {
+ static constexpr auto value = false;
+ };
+
+ template < typename T >
+ struct is_same<T, T>
+ {
+ static constexpr auto value = true;
+ };
+
+ int
+ test()
+ {
+ auto x = 0;
+ static_assert(is_same<int, decltype(f(x))>::value, "");
+ static_assert(is_same<int&, decltype(g(x))>::value, "");
+ return x;
+ }
+
+ }
+
+} // namespace cxx14
+
+#endif // __cplusplus >= 201402L
+
+]])
+
+
+dnl Tests for new features in C++17
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_17], [[
+
+// If the compiler admits that it is not ready for C++17, why torture it?
+// Hopefully, this will speed up the test.
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 201703L && !defined _MSC_VER
+
+#error "This is not a C++17 compiler"
+
+#else
+
+#include <initializer_list>
+#include <utility>
+#include <type_traits>
+
+namespace cxx17
+{
+
+ namespace test_constexpr_lambdas
+ {
+
+ constexpr int foo = [](){return 42;}();
+
+ }
+
+ namespace test::nested_namespace::definitions
+ {
+
+ }
+
+ namespace test_fold_expression
+ {
+
+ template<typename... Args>
+ int multiply(Args... args)
+ {
+ return (args * ... * 1);
+ }
+
+ template<typename... Args>
+ bool all(Args... args)
+ {
+ return (args && ...);
+ }
+
+ }
+
+ namespace test_extended_static_assert
+ {
+
+ static_assert (true);
+
+ }
+
+ namespace test_auto_brace_init_list
+ {
+
+ auto foo = {5};
+ 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 && !defined _MSC_VER
+
+]])
+
+
+dnl Tests for new features in C++20
+
+m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_20], [[
+
+#ifndef __cplusplus
+
+#error "This is not a C++ compiler"
+
+#elif __cplusplus < 202002L && !defined _MSC_VER
+
+#error "This is not a C++20 compiler"
+
+#else
+
+#include <version>
+
+namespace cxx20
+{
+
+// As C++20 supports feature test macros in the standard, there is no
+// immediate need to actually test for feature availability on the
+// Autoconf side.
+
+} // namespace cxx20
+
+#endif // __cplusplus < 202002L && !defined _MSC_VER
+
+]])