Brad Bishop | 6e60e8b | 2018-02-01 10:27:11 -0500 | [diff] [blame] | 1 | From ccb3eb7b4ff65414a56e2294080885b8966da52b Mon Sep 17 00:00:00 2001 |
| 2 | From: Arun Raghavan <git@arunraghavan.net> |
| 3 | Date: Tue, 2 Feb 2016 17:01:47 +0530 |
| 4 | Subject: [PATCH 2/2] build-sys: Add m4 file for AX_CXX_COMPILE_STDCXX_11 |
| 5 | |
| 6 | --- |
| 7 | m4/ax_cxx_compile_stdcxx.m4 | 558 +++++++++++++++++++++++++++++++++++++++++ |
| 8 | m4/ax_cxx_compile_stdcxx_11.m4 | 39 +++ |
| 9 | 2 files changed, 597 insertions(+) |
| 10 | create mode 100644 m4/ax_cxx_compile_stdcxx.m4 |
| 11 | create mode 100644 m4/ax_cxx_compile_stdcxx_11.m4 |
| 12 | |
| 13 | diff --git a/m4/ax_cxx_compile_stdcxx.m4 b/m4/ax_cxx_compile_stdcxx.m4 |
| 14 | new file mode 100644 |
| 15 | index 0000000..079e17d |
| 16 | --- /dev/null |
| 17 | +++ b/m4/ax_cxx_compile_stdcxx.m4 |
| 18 | @@ -0,0 +1,558 @@ |
| 19 | +# =========================================================================== |
| 20 | +# http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html |
| 21 | +# =========================================================================== |
| 22 | +# |
| 23 | +# SYNOPSIS |
| 24 | +# |
| 25 | +# AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional]) |
| 26 | +# |
| 27 | +# DESCRIPTION |
| 28 | +# |
| 29 | +# Check for baseline language coverage in the compiler for the specified |
| 30 | +# version of the C++ standard. If necessary, add switches to CXXFLAGS to |
| 31 | +# enable support. VERSION may be '11' (for the C++11 standard) or '14' |
| 32 | +# (for the C++14 standard). |
| 33 | +# |
| 34 | +# The second argument, if specified, indicates whether you insist on an |
| 35 | +# extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g. |
| 36 | +# -std=c++11). If neither is specified, you get whatever works, with |
| 37 | +# preference for an extended mode. |
| 38 | +# |
| 39 | +# The third argument, if specified 'mandatory' or if left unspecified, |
| 40 | +# indicates that baseline support for the specified C++ standard is |
| 41 | +# required and that the macro should error out if no mode with that |
| 42 | +# support is found. If specified 'optional', then configuration proceeds |
| 43 | +# regardless, after defining HAVE_CXX${VERSION} if and only if a |
| 44 | +# supporting mode is found. |
| 45 | +# |
| 46 | +# LICENSE |
| 47 | +# |
| 48 | +# Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com> |
| 49 | +# Copyright (c) 2012 Zack Weinberg <zackw@panix.com> |
| 50 | +# Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu> |
| 51 | +# Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com> |
| 52 | +# Copyright (c) 2015 Paul Norman <penorman@mac.com> |
| 53 | +# Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu> |
| 54 | +# |
| 55 | +# Copying and distribution of this file, with or without modification, are |
| 56 | +# permitted in any medium without royalty provided the copyright notice |
| 57 | +# and this notice are preserved. This file is offered as-is, without any |
| 58 | +# warranty. |
| 59 | + |
| 60 | +#serial 1 |
| 61 | + |
| 62 | +dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro |
| 63 | +dnl (serial version number 13). |
| 64 | + |
| 65 | +AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl |
| 66 | + m4_if([$1], [11], [], |
| 67 | + [$1], [14], [], |
| 68 | + [$1], [17], [m4_fatal([support for C++17 not yet implemented in AX_CXX_COMPILE_STDCXX])], |
| 69 | + [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl |
| 70 | + m4_if([$2], [], [], |
| 71 | + [$2], [ext], [], |
| 72 | + [$2], [noext], [], |
| 73 | + [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl |
| 74 | + m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true], |
| 75 | + [$3], [mandatory], [ax_cxx_compile_cxx$1_required=true], |
| 76 | + [$3], [optional], [ax_cxx_compile_cxx$1_required=false], |
| 77 | + [m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])]) |
| 78 | + AC_LANG_PUSH([C++])dnl |
| 79 | + ac_success=no |
| 80 | + AC_CACHE_CHECK(whether $CXX supports C++$1 features by default, |
| 81 | + ax_cv_cxx_compile_cxx$1, |
| 82 | + [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], |
| 83 | + [ax_cv_cxx_compile_cxx$1=yes], |
| 84 | + [ax_cv_cxx_compile_cxx$1=no])]) |
| 85 | + if test x$ax_cv_cxx_compile_cxx$1 = xyes; then |
| 86 | + ac_success=yes |
| 87 | + fi |
| 88 | + |
| 89 | + m4_if([$2], [noext], [], [dnl |
| 90 | + if test x$ac_success = xno; then |
| 91 | + for switch in -std=gnu++$1 -std=gnu++0x; do |
| 92 | + cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) |
| 93 | + AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, |
| 94 | + $cachevar, |
| 95 | + [ac_save_CXXFLAGS="$CXXFLAGS" |
| 96 | + CXXFLAGS="$CXXFLAGS $switch" |
| 97 | + AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], |
| 98 | + [eval $cachevar=yes], |
| 99 | + [eval $cachevar=no]) |
| 100 | + CXXFLAGS="$ac_save_CXXFLAGS"]) |
| 101 | + if eval test x\$$cachevar = xyes; then |
| 102 | + CXXFLAGS="$CXXFLAGS $switch" |
| 103 | + ac_success=yes |
| 104 | + break |
| 105 | + fi |
| 106 | + done |
| 107 | + fi]) |
| 108 | + |
| 109 | + m4_if([$2], [ext], [], [dnl |
| 110 | + if test x$ac_success = xno; then |
| 111 | + dnl HP's aCC needs +std=c++11 according to: |
| 112 | + dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf |
| 113 | + dnl Cray's crayCC needs "-h std=c++11" |
| 114 | + for switch in -std=c++$1 -std=c++0x +std=c++$1 "-h std=c++$1"; do |
| 115 | + cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) |
| 116 | + AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, |
| 117 | + $cachevar, |
| 118 | + [ac_save_CXXFLAGS="$CXXFLAGS" |
| 119 | + CXXFLAGS="$CXXFLAGS $switch" |
| 120 | + AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], |
| 121 | + [eval $cachevar=yes], |
| 122 | + [eval $cachevar=no]) |
| 123 | + CXXFLAGS="$ac_save_CXXFLAGS"]) |
| 124 | + if eval test x\$$cachevar = xyes; then |
| 125 | + CXXFLAGS="$CXXFLAGS $switch" |
| 126 | + ac_success=yes |
| 127 | + break |
| 128 | + fi |
| 129 | + done |
| 130 | + fi]) |
| 131 | + AC_LANG_POP([C++]) |
| 132 | + if test x$ax_cxx_compile_cxx$1_required = xtrue; then |
| 133 | + if test x$ac_success = xno; then |
| 134 | + AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.]) |
| 135 | + fi |
| 136 | + else |
| 137 | + if test x$ac_success = xno; then |
| 138 | + HAVE_CXX$1=0 |
| 139 | + AC_MSG_NOTICE([No compiler with C++$1 support was found]) |
| 140 | + else |
| 141 | + HAVE_CXX$1=1 |
| 142 | + AC_DEFINE(HAVE_CXX$1,1, |
| 143 | + [define if the compiler supports basic C++$1 syntax]) |
| 144 | + fi |
| 145 | + |
| 146 | + AC_SUBST(HAVE_CXX$1) |
| 147 | + fi |
| 148 | +]) |
| 149 | + |
| 150 | + |
| 151 | +dnl Test body for checking C++11 support |
| 152 | + |
| 153 | +m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11], |
| 154 | + _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 |
| 155 | +) |
| 156 | + |
| 157 | + |
| 158 | +dnl Test body for checking C++14 support |
| 159 | + |
| 160 | +m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14], |
| 161 | + _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 |
| 162 | + _AX_CXX_COMPILE_STDCXX_testbody_new_in_14 |
| 163 | +) |
| 164 | + |
| 165 | + |
| 166 | +dnl Tests for new features in C++11 |
| 167 | + |
| 168 | +m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[ |
| 169 | + |
| 170 | +// If the compiler admits that it is not ready for C++11, why torture it? |
| 171 | +// Hopefully, this will speed up the test. |
| 172 | + |
| 173 | +#ifndef __cplusplus |
| 174 | + |
| 175 | +#error "This is not a C++ compiler" |
| 176 | + |
| 177 | +#elif __cplusplus < 201103L |
| 178 | + |
| 179 | +#error "This is not a C++11 compiler" |
| 180 | + |
| 181 | +#else |
| 182 | + |
| 183 | +namespace cxx11 |
| 184 | +{ |
| 185 | + |
| 186 | + namespace test_static_assert |
| 187 | + { |
| 188 | + |
| 189 | + template <typename T> |
| 190 | + struct check |
| 191 | + { |
| 192 | + static_assert(sizeof(int) <= sizeof(T), "not big enough"); |
| 193 | + }; |
| 194 | + |
| 195 | + } |
| 196 | + |
| 197 | + namespace test_final_override |
| 198 | + { |
| 199 | + |
| 200 | + struct Base |
| 201 | + { |
| 202 | + virtual void f() {} |
| 203 | + }; |
| 204 | + |
| 205 | + struct Derived : public Base |
| 206 | + { |
| 207 | + virtual void f() override {} |
| 208 | + }; |
| 209 | + |
| 210 | + } |
| 211 | + |
| 212 | + namespace test_double_right_angle_brackets |
| 213 | + { |
| 214 | + |
| 215 | + template < typename T > |
| 216 | + struct check {}; |
| 217 | + |
| 218 | + typedef check<void> single_type; |
| 219 | + typedef check<check<void>> double_type; |
| 220 | + typedef check<check<check<void>>> triple_type; |
| 221 | + typedef check<check<check<check<void>>>> quadruple_type; |
| 222 | + |
| 223 | + } |
| 224 | + |
| 225 | + namespace test_decltype |
| 226 | + { |
| 227 | + |
| 228 | + int |
| 229 | + f() |
| 230 | + { |
| 231 | + int a = 1; |
| 232 | + decltype(a) b = 2; |
| 233 | + return a + b; |
| 234 | + } |
| 235 | + |
| 236 | + } |
| 237 | + |
| 238 | + namespace test_type_deduction |
| 239 | + { |
| 240 | + |
| 241 | + template < typename T1, typename T2 > |
| 242 | + struct is_same |
| 243 | + { |
| 244 | + static const bool value = false; |
| 245 | + }; |
| 246 | + |
| 247 | + template < typename T > |
| 248 | + struct is_same<T, T> |
| 249 | + { |
| 250 | + static const bool value = true; |
| 251 | + }; |
| 252 | + |
| 253 | + template < typename T1, typename T2 > |
| 254 | + auto |
| 255 | + add(T1 a1, T2 a2) -> decltype(a1 + a2) |
| 256 | + { |
| 257 | + return a1 + a2; |
| 258 | + } |
| 259 | + |
| 260 | + int |
| 261 | + test(const int c, volatile int v) |
| 262 | + { |
| 263 | + static_assert(is_same<int, decltype(0)>::value == true, ""); |
| 264 | + static_assert(is_same<int, decltype(c)>::value == false, ""); |
| 265 | + static_assert(is_same<int, decltype(v)>::value == false, ""); |
| 266 | + auto ac = c; |
| 267 | + auto av = v; |
| 268 | + auto sumi = ac + av + 'x'; |
| 269 | + auto sumf = ac + av + 1.0; |
| 270 | + static_assert(is_same<int, decltype(ac)>::value == true, ""); |
| 271 | + static_assert(is_same<int, decltype(av)>::value == true, ""); |
| 272 | + static_assert(is_same<int, decltype(sumi)>::value == true, ""); |
| 273 | + static_assert(is_same<int, decltype(sumf)>::value == false, ""); |
| 274 | + static_assert(is_same<int, decltype(add(c, v))>::value == true, ""); |
| 275 | + return (sumf > 0.0) ? sumi : add(c, v); |
| 276 | + } |
| 277 | + |
| 278 | + } |
| 279 | + |
| 280 | + namespace test_noexcept |
| 281 | + { |
| 282 | + |
| 283 | + int f() { return 0; } |
| 284 | + int g() noexcept { return 0; } |
| 285 | + |
| 286 | + static_assert(noexcept(f()) == false, ""); |
| 287 | + static_assert(noexcept(g()) == true, ""); |
| 288 | + |
| 289 | + } |
| 290 | + |
| 291 | + namespace test_constexpr |
| 292 | + { |
| 293 | + |
| 294 | + template < typename CharT > |
| 295 | + unsigned long constexpr |
| 296 | + strlen_c_r(const CharT *const s, const unsigned long acc) noexcept |
| 297 | + { |
| 298 | + return *s ? strlen_c_r(s + 1, acc + 1) : acc; |
| 299 | + } |
| 300 | + |
| 301 | + template < typename CharT > |
| 302 | + unsigned long constexpr |
| 303 | + strlen_c(const CharT *const s) noexcept |
| 304 | + { |
| 305 | + return strlen_c_r(s, 0UL); |
| 306 | + } |
| 307 | + |
| 308 | + static_assert(strlen_c("") == 0UL, ""); |
| 309 | + static_assert(strlen_c("1") == 1UL, ""); |
| 310 | + static_assert(strlen_c("example") == 7UL, ""); |
| 311 | + static_assert(strlen_c("another\0example") == 7UL, ""); |
| 312 | + |
| 313 | + } |
| 314 | + |
| 315 | + namespace test_rvalue_references |
| 316 | + { |
| 317 | + |
| 318 | + template < int N > |
| 319 | + struct answer |
| 320 | + { |
| 321 | + static constexpr int value = N; |
| 322 | + }; |
| 323 | + |
| 324 | + answer<1> f(int&) { return answer<1>(); } |
| 325 | + answer<2> f(const int&) { return answer<2>(); } |
| 326 | + answer<3> f(int&&) { return answer<3>(); } |
| 327 | + |
| 328 | + void |
| 329 | + test() |
| 330 | + { |
| 331 | + int i = 0; |
| 332 | + const int c = 0; |
| 333 | + static_assert(decltype(f(i))::value == 1, ""); |
| 334 | + static_assert(decltype(f(c))::value == 2, ""); |
| 335 | + static_assert(decltype(f(0))::value == 3, ""); |
| 336 | + } |
| 337 | + |
| 338 | + } |
| 339 | + |
| 340 | + namespace test_uniform_initialization |
| 341 | + { |
| 342 | + |
| 343 | + struct test |
| 344 | + { |
| 345 | + static const int zero {}; |
| 346 | + static const int one {1}; |
| 347 | + }; |
| 348 | + |
| 349 | + static_assert(test::zero == 0, ""); |
| 350 | + static_assert(test::one == 1, ""); |
| 351 | + |
| 352 | + } |
| 353 | + |
| 354 | + namespace test_lambdas |
| 355 | + { |
| 356 | + |
| 357 | + void |
| 358 | + test1() |
| 359 | + { |
| 360 | + auto lambda1 = [](){}; |
| 361 | + auto lambda2 = lambda1; |
| 362 | + lambda1(); |
| 363 | + lambda2(); |
| 364 | + } |
| 365 | + |
| 366 | + int |
| 367 | + test2() |
| 368 | + { |
| 369 | + auto a = [](int i, int j){ return i + j; }(1, 2); |
| 370 | + auto b = []() -> int { return '0'; }(); |
| 371 | + auto c = [=](){ return a + b; }(); |
| 372 | + auto d = [&](){ return c; }(); |
| 373 | + auto e = [a, &b](int x) mutable { |
| 374 | + const auto identity = [](int y){ return y; }; |
| 375 | + for (auto i = 0; i < a; ++i) |
| 376 | + a += b--; |
| 377 | + return x + identity(a + b); |
| 378 | + }(0); |
| 379 | + return a + b + c + d + e; |
| 380 | + } |
| 381 | + |
| 382 | + int |
| 383 | + test3() |
| 384 | + { |
| 385 | + const auto nullary = [](){ return 0; }; |
| 386 | + const auto unary = [](int x){ return x; }; |
| 387 | + using nullary_t = decltype(nullary); |
| 388 | + using unary_t = decltype(unary); |
| 389 | + const auto higher1st = [](nullary_t f){ return f(); }; |
| 390 | + const auto higher2nd = [unary](nullary_t f1){ |
| 391 | + return [unary, f1](unary_t f2){ return f2(unary(f1())); }; |
| 392 | + }; |
| 393 | + return higher1st(nullary) + higher2nd(nullary)(unary); |
| 394 | + } |
| 395 | + |
| 396 | + } |
| 397 | + |
| 398 | + namespace test_variadic_templates |
| 399 | + { |
| 400 | + |
| 401 | + template <int...> |
| 402 | + struct sum; |
| 403 | + |
| 404 | + template <int N0, int... N1toN> |
| 405 | + struct sum<N0, N1toN...> |
| 406 | + { |
| 407 | + static constexpr auto value = N0 + sum<N1toN...>::value; |
| 408 | + }; |
| 409 | + |
| 410 | + template <> |
| 411 | + struct sum<> |
| 412 | + { |
| 413 | + static constexpr auto value = 0; |
| 414 | + }; |
| 415 | + |
| 416 | + static_assert(sum<>::value == 0, ""); |
| 417 | + static_assert(sum<1>::value == 1, ""); |
| 418 | + static_assert(sum<23>::value == 23, ""); |
| 419 | + static_assert(sum<1, 2>::value == 3, ""); |
| 420 | + static_assert(sum<5, 5, 11>::value == 21, ""); |
| 421 | + static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, ""); |
| 422 | + |
| 423 | + } |
| 424 | + |
| 425 | + // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae |
| 426 | + // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function |
| 427 | + // because of this. |
| 428 | + namespace test_template_alias_sfinae |
| 429 | + { |
| 430 | + |
| 431 | + struct foo {}; |
| 432 | + |
| 433 | + template<typename T> |
| 434 | + using member = typename T::member_type; |
| 435 | + |
| 436 | + template<typename T> |
| 437 | + void func(...) {} |
| 438 | + |
| 439 | + template<typename T> |
| 440 | + void func(member<T>*) {} |
| 441 | + |
| 442 | + void test(); |
| 443 | + |
| 444 | + void test() { func<foo>(0); } |
| 445 | + |
| 446 | + } |
| 447 | + |
| 448 | +} // namespace cxx11 |
| 449 | + |
| 450 | +#endif // __cplusplus >= 201103L |
| 451 | + |
| 452 | +]]) |
| 453 | + |
| 454 | + |
| 455 | +dnl Tests for new features in C++14 |
| 456 | + |
| 457 | +m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[ |
| 458 | + |
| 459 | +// If the compiler admits that it is not ready for C++14, why torture it? |
| 460 | +// Hopefully, this will speed up the test. |
| 461 | + |
| 462 | +#ifndef __cplusplus |
| 463 | + |
| 464 | +#error "This is not a C++ compiler" |
| 465 | + |
| 466 | +#elif __cplusplus < 201402L |
| 467 | + |
| 468 | +#error "This is not a C++14 compiler" |
| 469 | + |
| 470 | +#else |
| 471 | + |
| 472 | +namespace cxx14 |
| 473 | +{ |
| 474 | + |
| 475 | + namespace test_polymorphic_lambdas |
| 476 | + { |
| 477 | + |
| 478 | + int |
| 479 | + test() |
| 480 | + { |
| 481 | + const auto lambda = [](auto&&... args){ |
| 482 | + const auto istiny = [](auto x){ |
| 483 | + return (sizeof(x) == 1UL) ? 1 : 0; |
| 484 | + }; |
| 485 | + const int aretiny[] = { istiny(args)... }; |
| 486 | + return aretiny[0]; |
| 487 | + }; |
| 488 | + return lambda(1, 1L, 1.0f, '1'); |
| 489 | + } |
| 490 | + |
| 491 | + } |
| 492 | + |
| 493 | + namespace test_binary_literals |
| 494 | + { |
| 495 | + |
| 496 | + constexpr auto ivii = 0b0000000000101010; |
| 497 | + static_assert(ivii == 42, "wrong value"); |
| 498 | + |
| 499 | + } |
| 500 | + |
| 501 | + namespace test_generalized_constexpr |
| 502 | + { |
| 503 | + |
| 504 | + template < typename CharT > |
| 505 | + constexpr unsigned long |
| 506 | + strlen_c(const CharT *const s) noexcept |
| 507 | + { |
| 508 | + auto length = 0UL; |
| 509 | + for (auto p = s; *p; ++p) |
| 510 | + ++length; |
| 511 | + return length; |
| 512 | + } |
| 513 | + |
| 514 | + static_assert(strlen_c("") == 0UL, ""); |
| 515 | + static_assert(strlen_c("x") == 1UL, ""); |
| 516 | + static_assert(strlen_c("test") == 4UL, ""); |
| 517 | + static_assert(strlen_c("another\0test") == 7UL, ""); |
| 518 | + |
| 519 | + } |
| 520 | + |
| 521 | + namespace test_lambda_init_capture |
| 522 | + { |
| 523 | + |
| 524 | + int |
| 525 | + test() |
| 526 | + { |
| 527 | + auto x = 0; |
| 528 | + const auto lambda1 = [a = x](int b){ return a + b; }; |
| 529 | + const auto lambda2 = [a = lambda1(x)](){ return a; }; |
| 530 | + return lambda2(); |
| 531 | + } |
| 532 | + |
| 533 | + } |
| 534 | + |
| 535 | + namespace test_digit_seperators |
| 536 | + { |
| 537 | + |
| 538 | + constexpr auto ten_million = 100'000'000; |
| 539 | + static_assert(ten_million == 100000000, ""); |
| 540 | + |
| 541 | + } |
| 542 | + |
| 543 | + namespace test_return_type_deduction |
| 544 | + { |
| 545 | + |
| 546 | + auto f(int& x) { return x; } |
| 547 | + decltype(auto) g(int& x) { return x; } |
| 548 | + |
| 549 | + template < typename T1, typename T2 > |
| 550 | + struct is_same |
| 551 | + { |
| 552 | + static constexpr auto value = false; |
| 553 | + }; |
| 554 | + |
| 555 | + template < typename T > |
| 556 | + struct is_same<T, T> |
| 557 | + { |
| 558 | + static constexpr auto value = true; |
| 559 | + }; |
| 560 | + |
| 561 | + int |
| 562 | + test() |
| 563 | + { |
| 564 | + auto x = 0; |
| 565 | + static_assert(is_same<int, decltype(f(x))>::value, ""); |
| 566 | + static_assert(is_same<int&, decltype(g(x))>::value, ""); |
| 567 | + return x; |
| 568 | + } |
| 569 | + |
| 570 | + } |
| 571 | + |
| 572 | +} // namespace cxx14 |
| 573 | + |
| 574 | +#endif // __cplusplus >= 201402L |
| 575 | + |
| 576 | +]]) |
| 577 | diff --git a/m4/ax_cxx_compile_stdcxx_11.m4 b/m4/ax_cxx_compile_stdcxx_11.m4 |
| 578 | new file mode 100644 |
| 579 | index 0000000..09db383 |
| 580 | --- /dev/null |
| 581 | +++ b/m4/ax_cxx_compile_stdcxx_11.m4 |
| 582 | @@ -0,0 +1,39 @@ |
| 583 | +# ============================================================================ |
| 584 | +# http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html |
| 585 | +# ============================================================================ |
| 586 | +# |
| 587 | +# SYNOPSIS |
| 588 | +# |
| 589 | +# AX_CXX_COMPILE_STDCXX_11([ext|noext], [mandatory|optional]) |
| 590 | +# |
| 591 | +# DESCRIPTION |
| 592 | +# |
| 593 | +# Check for baseline language coverage in the compiler for the C++11 |
| 594 | +# standard; if necessary, add switches to CXXFLAGS to enable support. |
| 595 | +# |
| 596 | +# This macro is a convenience alias for calling the AX_CXX_COMPILE_STDCXX |
| 597 | +# macro with the version set to C++11. The two optional arguments are |
| 598 | +# forwarded literally as the second and third argument respectively. |
| 599 | +# Please see the documentation for the AX_CXX_COMPILE_STDCXX macro for |
| 600 | +# more information. If you want to use this macro, you also need to |
| 601 | +# download the ax_cxx_compile_stdcxx.m4 file. |
| 602 | +# |
| 603 | +# LICENSE |
| 604 | +# |
| 605 | +# Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com> |
| 606 | +# Copyright (c) 2012 Zack Weinberg <zackw@panix.com> |
| 607 | +# Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu> |
| 608 | +# Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com> |
| 609 | +# Copyright (c) 2015 Paul Norman <penorman@mac.com> |
| 610 | +# Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu> |
| 611 | +# |
| 612 | +# Copying and distribution of this file, with or without modification, are |
| 613 | +# permitted in any medium without royalty provided the copyright notice |
| 614 | +# and this notice are preserved. This file is offered as-is, without any |
| 615 | +# warranty. |
| 616 | + |
| 617 | +#serial 14 |
| 618 | + |
| 619 | +include([ax_cxx_compile_stdcxx.m4]) |
| 620 | + |
| 621 | +AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [AX_CXX_COMPILE_STDCXX([11], [$1], [$2])]) |
| 622 | -- |
| 623 | 2.12.1 |
| 624 | |