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view m4/ax_cxx_compile_stdcxx.m4 @ 31605:e88a07dec498 stable
maint: Use macros to begin/end C++ namespaces.
* oct-conf-post-public.in.h: Define two macros (OCTAVE_BEGIN_NAMESPACE,
OCTAVE_END_NAMESPACE) that can be used to start/end a namespace.
* mk-opts.pl, build-env.h, build-env.in.cc, __betainc__.cc, __contourc__.cc,
__dsearchn__.cc, __eigs__.cc, __expint__.cc, __ftp__.cc, __gammainc__.cc,
__ichol__.cc, __ilu__.cc, __isprimelarge__.cc, __lin_interpn__.cc,
__magick_read__.cc, __pchip_deriv__.cc, __qp__.cc, amd.cc, auto-shlib.cc,
auto-shlib.h, balance.cc, base-text-renderer.cc, base-text-renderer.h,
besselj.cc, bitfcns.cc, bsxfun.cc, c-file-ptr-stream.cc, c-file-ptr-stream.h,
call-stack.cc, call-stack.h, ccolamd.cc, cellfun.cc, chol.cc, colamd.cc,
colloc.cc, conv2.cc, daspk.cc, dasrt.cc, dassl.cc, data.cc, data.h, debug.cc,
defaults.cc, defaults.h, defun-int.h, defun.cc, det.cc, dirfns.cc, display.cc,
display.h, dlmread.cc, dmperm.cc, dot.cc, dynamic-ld.cc, dynamic-ld.h, eig.cc,
ellipj.cc, environment.cc, environment.h, error.cc, error.h, errwarn.h,
event-manager.cc, event-manager.h, event-queue.cc, event-queue.h, fcn-info.cc,
fcn-info.h, fft.cc, fft2.cc, fftn.cc, file-io.cc, filter.cc, find.cc,
ft-text-renderer.cc, ft-text-renderer.h, gcd.cc, getgrent.cc, getpwent.cc,
getrusage.cc, givens.cc, gl-render.cc, gl-render.h, gl2ps-print.cc,
gl2ps-print.h, graphics-toolkit.cc, graphics-toolkit.h, graphics.cc,
graphics.in.h, gsvd.cc, gtk-manager.cc, gtk-manager.h, hash.cc, help.cc,
help.h, hess.cc, hex2num.cc, hook-fcn.cc, hook-fcn.h, input.cc, input.h,
interpreter-private.cc, interpreter-private.h, interpreter.cc, interpreter.h,
inv.cc, jsondecode.cc, jsonencode.cc, kron.cc, latex-text-renderer.cc,
latex-text-renderer.h, load-path.cc, load-path.h, load-save.cc, load-save.h,
lookup.cc, ls-ascii-helper.cc, ls-ascii-helper.h, ls-oct-text.cc, ls-utils.cc,
ls-utils.h, lsode.cc, lu.cc, mappers.cc, matrix_type.cc, max.cc, mex-private.h,
mex.cc, mgorth.cc, nproc.cc, oct-fstrm.cc, oct-fstrm.h, oct-hdf5-types.cc,
oct-hdf5-types.h, oct-hist.cc, oct-hist.h, oct-iostrm.cc, oct-iostrm.h,
oct-opengl.h, oct-prcstrm.cc, oct-prcstrm.h, oct-procbuf.cc, oct-procbuf.h,
oct-process.cc, oct-process.h, oct-stdstrm.h, oct-stream.cc, oct-stream.h,
oct-strstrm.cc, oct-strstrm.h, oct-tex-lexer.in.ll, oct-tex-parser.yy,
ordqz.cc, ordschur.cc, pager.cc, pager.h, pinv.cc, pow2.cc, pr-flt-fmt.cc,
pr-output.cc, procstream.cc, procstream.h, psi.cc, qr.cc, quad.cc, quadcc.cc,
qz.cc, rand.cc, rcond.cc, regexp.cc, schur.cc, settings.cc, settings.h,
sighandlers.cc, sighandlers.h, sparse-xdiv.cc, sparse-xdiv.h, sparse-xpow.cc,
sparse-xpow.h, sparse.cc, spparms.cc, sqrtm.cc, stack-frame.cc, stack-frame.h,
stream-euler.cc, strfind.cc, strfns.cc, sub2ind.cc, svd.cc, sylvester.cc,
symbfact.cc, syminfo.cc, syminfo.h, symrcm.cc, symrec.cc, symrec.h,
symscope.cc, symscope.h, symtab.cc, symtab.h, syscalls.cc, sysdep.cc, sysdep.h,
text-engine.cc, text-engine.h, text-renderer.cc, text-renderer.h, time.cc,
toplev.cc, tril.cc, tsearch.cc, typecast.cc, url-handle-manager.cc,
url-handle-manager.h, urlwrite.cc, utils.cc, utils.h, variables.cc,
variables.h, xdiv.cc, xdiv.h, xnorm.cc, xnorm.h, xpow.cc, xpow.h,
__delaunayn__.cc, __fltk_uigetfile__.cc, __glpk__.cc, __init_fltk__.cc,
__init_gnuplot__.cc, __ode15__.cc, __voronoi__.cc, audiodevinfo.cc,
audioread.cc, convhulln.cc, fftw.cc, gzip.cc, mk-build-env-features.sh,
mk-builtins.pl, cdef-class.cc, cdef-class.h, cdef-fwd.h, cdef-manager.cc,
cdef-manager.h, cdef-method.cc, cdef-method.h, cdef-object.cc, cdef-object.h,
cdef-package.cc, cdef-package.h, cdef-property.cc, cdef-property.h,
cdef-utils.cc, cdef-utils.h, ov-base.cc, ov-base.h, ov-bool-mat.cc,
ov-builtin.h, ov-cell.cc, ov-class.cc, ov-class.h, ov-classdef.cc,
ov-classdef.h, ov-complex.cc, ov-fcn-handle.cc, ov-fcn-handle.h, ov-fcn.h,
ov-java.cc, ov-java.h, ov-mex-fcn.h, ov-null-mat.cc, ov-oncleanup.cc,
ov-struct.cc, ov-typeinfo.cc, ov-typeinfo.h, ov-usr-fcn.cc, ov-usr-fcn.h,
ov.cc, ov.h, octave.cc, octave.h, mk-ops.sh, op-b-b.cc, op-b-bm.cc,
op-b-sbm.cc, op-bm-b.cc, op-bm-bm.cc, op-bm-sbm.cc, op-cdm-cdm.cc, op-cell.cc,
op-chm.cc, op-class.cc, op-cm-cm.cc, op-cm-cs.cc, op-cm-m.cc, op-cm-s.cc,
op-cm-scm.cc, op-cm-sm.cc, op-cs-cm.cc, op-cs-cs.cc, op-cs-m.cc, op-cs-s.cc,
op-cs-scm.cc, op-cs-sm.cc, op-dm-dm.cc, op-dm-scm.cc, op-dm-sm.cc,
op-dm-template.cc, op-dms-template.cc, op-fcdm-fcdm.cc, op-fcm-fcm.cc,
op-fcm-fcs.cc, op-fcm-fm.cc, op-fcm-fs.cc, op-fcn.cc, op-fcs-fcm.cc,
op-fcs-fcs.cc, op-fcs-fm.cc, op-fcs-fs.cc, op-fdm-fdm.cc, op-fm-fcm.cc,
op-fm-fcs.cc, op-fm-fm.cc, op-fm-fs.cc, op-fs-fcm.cc, op-fs-fcs.cc,
op-fs-fm.cc, op-fs-fs.cc, op-i16-i16.cc, op-i32-i32.cc, op-i64-i64.cc,
op-i8-i8.cc, op-int-concat.cc, op-m-cm.cc, op-m-cs.cc, op-m-m.cc, op-m-s.cc,
op-m-scm.cc, op-m-sm.cc, op-mi.cc, op-pm-pm.cc, op-pm-scm.cc, op-pm-sm.cc,
op-pm-template.cc, op-range.cc, op-s-cm.cc, op-s-cs.cc, op-s-m.cc, op-s-s.cc,
op-s-scm.cc, op-s-sm.cc, op-sbm-b.cc, op-sbm-bm.cc, op-sbm-sbm.cc,
op-scm-cm.cc, op-scm-cs.cc, op-scm-m.cc, op-scm-s.cc, op-scm-scm.cc,
op-scm-sm.cc, op-sm-cm.cc, op-sm-cs.cc, op-sm-m.cc, op-sm-s.cc, op-sm-scm.cc,
op-sm-sm.cc, op-str-m.cc, op-str-s.cc, op-str-str.cc, op-struct.cc,
op-ui16-ui16.cc, op-ui32-ui32.cc, op-ui64-ui64.cc, op-ui8-ui8.cc, ops.h,
anon-fcn-validator.cc, anon-fcn-validator.h, bp-table.cc, bp-table.h,
comment-list.cc, comment-list.h, filepos.h, lex.h, lex.ll, oct-lvalue.cc,
oct-lvalue.h, oct-parse.yy, parse.h, profiler.cc, profiler.h,
pt-anon-scopes.cc, pt-anon-scopes.h, pt-arg-list.cc, pt-arg-list.h,
pt-args-block.cc, pt-args-block.h, pt-array-list.cc, pt-array-list.h,
pt-assign.cc, pt-assign.h, pt-binop.cc, pt-binop.h, pt-bp.cc, pt-bp.h,
pt-cbinop.cc, pt-cbinop.h, pt-cell.cc, pt-cell.h, pt-check.cc, pt-check.h,
pt-classdef.cc, pt-classdef.h, pt-cmd.h, pt-colon.cc, pt-colon.h, pt-const.cc,
pt-const.h, pt-decl.cc, pt-decl.h, pt-eval.cc, pt-eval.h, pt-except.cc,
pt-except.h, pt-exp.cc, pt-exp.h, pt-fcn-handle.cc, pt-fcn-handle.h, pt-id.cc,
pt-id.h, pt-idx.cc, pt-idx.h, pt-jump.h, pt-loop.cc, pt-loop.h, pt-mat.cc,
pt-mat.h, pt-misc.cc, pt-misc.h, pt-pr-code.cc, pt-pr-code.h, pt-select.cc,
pt-select.h, pt-spmd.cc, pt-spmd.h, pt-stmt.cc, pt-stmt.h, pt-tm-const.cc,
pt-tm-const.h, pt-unop.cc, pt-unop.h, pt-vm-eval.cc, pt-walk.cc, pt-walk.h,
pt.cc, pt.h, token.cc, token.h, Range.cc, Range.h, idx-vector.cc, idx-vector.h,
range-fwd.h, CollocWt.cc, CollocWt.h, aepbalance.cc, aepbalance.h, chol.cc,
chol.h, gepbalance.cc, gepbalance.h, gsvd.cc, gsvd.h, hess.cc, hess.h,
lo-mappers.cc, lo-mappers.h, lo-specfun.cc, lo-specfun.h, lu.cc, lu.h,
oct-convn.cc, oct-convn.h, oct-fftw.cc, oct-fftw.h, oct-norm.cc, oct-norm.h,
oct-rand.cc, oct-rand.h, oct-spparms.cc, oct-spparms.h, qr.cc, qr.h, qrp.cc,
qrp.h, randgamma.cc, randgamma.h, randmtzig.cc, randmtzig.h, randpoisson.cc,
randpoisson.h, schur.cc, schur.h, sparse-chol.cc, sparse-chol.h, sparse-lu.cc,
sparse-lu.h, sparse-qr.cc, sparse-qr.h, svd.cc, svd.h, child-list.cc,
child-list.h, dir-ops.cc, dir-ops.h, file-ops.cc, file-ops.h, file-stat.cc,
file-stat.h, lo-sysdep.cc, lo-sysdep.h, lo-sysinfo.cc, lo-sysinfo.h,
mach-info.cc, mach-info.h, oct-env.cc, oct-env.h, oct-group.cc, oct-group.h,
oct-password.cc, oct-password.h, oct-syscalls.cc, oct-syscalls.h, oct-time.cc,
oct-time.h, oct-uname.cc, oct-uname.h, action-container.cc, action-container.h,
base-list.h, cmd-edit.cc, cmd-edit.h, cmd-hist.cc, cmd-hist.h, f77-fcn.h,
file-info.cc, file-info.h, lo-array-errwarn.cc, lo-array-errwarn.h, lo-hash.cc,
lo-hash.h, lo-ieee.h, lo-regexp.cc, lo-regexp.h, lo-utils.cc, lo-utils.h,
oct-base64.cc, oct-base64.h, oct-glob.cc, oct-glob.h, oct-inttypes.h,
oct-mutex.cc, oct-mutex.h, oct-refcount.h, oct-shlib.cc, oct-shlib.h,
oct-sparse.cc, oct-sparse.h, oct-string.h, octave-preserve-stream-state.h,
pathsearch.cc, pathsearch.h, quit.cc, quit.h, unwind-prot.cc, unwind-prot.h,
url-transfer.cc, url-transfer.h : Use new macros to begin/end C++ namespaces.
author | Rik <rik@octave.org> |
---|---|
date | Thu, 01 Dec 2022 14:23:45 -0800 |
parents | c8c947e1f05c |
children | 7714577c87dd |
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# =========================================================================== # 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 Jรถrn 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 14 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" for alternative in ${ax_cxx_compile_alternatives}; do for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${alternative}"; do 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 $switch" fi ac_success=yes break fi done if test x$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" #elif __cplusplus < 201103L #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 #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 #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 ]]) 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 #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 ]])