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| 1 # =========================================================================== |
| 2 # http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html |
| 3 # =========================================================================== |
| 4 # |
| 5 # SYNOPSIS |
| 6 # |
| 7 # AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional]) |
| 8 # |
| 9 # DESCRIPTION |
| 10 # |
| 11 # Check for baseline language coverage in the compiler for the specified |
| 12 # version of the C++ standard. If necessary, add switches to CXX and |
| 13 # CXXCPP to enable support. VERSION may be '11' (for the C++11 standard) |
| 14 # or '14' (for the C++14 standard). |
| 15 # |
| 16 # The second argument, if specified, indicates whether you insist on an |
| 17 # extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g. |
| 18 # -std=c++11). If neither is specified, you get whatever works, with |
| 19 # preference for an extended mode. |
| 20 # |
| 21 # The third argument, if specified 'mandatory' or if left unspecified, |
| 22 # indicates that baseline support for the specified C++ standard is |
| 23 # required and that the macro should error out if no mode with that |
| 24 # support is found. If specified 'optional', then configuration proceeds |
| 25 # regardless, after defining HAVE_CXX${VERSION} if and only if a |
| 26 # supporting mode is found. |
| 27 # |
| 28 # LICENSE |
| 29 # |
| 30 # Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com> |
| 31 # Copyright (c) 2012 Zack Weinberg <zackw@panix.com> |
| 32 # Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu> |
| 33 # Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov
@google.com> |
| 34 # Copyright (c) 2015 Paul Norman <penorman@mac.com> |
| 35 # Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu> |
| 36 # Copyright (c) 2016 Krzesimir Nowak <qdlacz@gmail.com> |
| 37 # |
| 38 # Copying and distribution of this file, with or without modification, are |
| 39 # permitted in any medium without royalty provided the copyright notice |
| 40 # and this notice are preserved. This file is offered as-is, without any |
| 41 # warranty. |
| 42 |
| 43 #serial 6 |
| 44 |
| 45 dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro |
| 46 dnl (serial version number 13). |
| 47 |
| 48 AX_REQUIRE_DEFINED([AC_MSG_WARN]) |
| 49 AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl |
| 50 m4_if([$1], [11], [ax_cxx_compile_alternatives="11 0x"], |
| 51 [$1], [14], [ax_cxx_compile_alternatives="14 1y"], |
| 52 [$1], [17], [ax_cxx_compile_alternatives="17 1z"], |
| 53 [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl |
| 54 m4_if([$2], [], [], |
| 55 [$2], [ext], [], |
| 56 [$2], [noext], [], |
| 57 [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl |
| 58 m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true], |
| 59 [$3], [mandatory], [ax_cxx_compile_cxx$1_required=true], |
| 60 [$3], [optional], [ax_cxx_compile_cxx$1_required=false], |
| 61 [m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])]) |
| 62 AC_LANG_PUSH([C++])dnl |
| 63 ac_success=no |
| 64 AC_CACHE_CHECK(whether $CXX supports C++$1 features by default, |
| 65 ax_cv_cxx_compile_cxx$1, |
| 66 [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], |
| 67 [ax_cv_cxx_compile_cxx$1=yes], |
| 68 [ax_cv_cxx_compile_cxx$1=no])]) |
| 69 if test x$ax_cv_cxx_compile_cxx$1 = xyes; then |
| 70 ac_success=yes |
| 71 fi |
| 72 |
| 73 m4_if([$2], [noext], [], [dnl |
| 74 if test x$ac_success = xno; then |
| 75 for alternative in ${ax_cxx_compile_alternatives}; do |
| 76 switch="-std=gnu++${alternative}" |
| 77 cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) |
| 78 AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, |
| 79 $cachevar, |
| 80 [ac_save_CXX="$CXX" |
| 81 CXX="$CXX $switch" |
| 82 AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])
], |
| 83 [eval $cachevar=yes], |
| 84 [eval $cachevar=no]) |
| 85 CXX="$ac_save_CXX"]) |
| 86 if eval test x\$$cachevar = xyes; then |
| 87 CXX="$CXX $switch" |
| 88 if test -n "$CXXCPP" ; then |
| 89 CXXCPP="$CXXCPP $switch" |
| 90 fi |
| 91 ac_success=yes |
| 92 break |
| 93 fi |
| 94 done |
| 95 fi]) |
| 96 |
| 97 m4_if([$2], [ext], [], [dnl |
| 98 if test x$ac_success = xno; then |
| 99 dnl HP's aCC needs +std=c++11 according to: |
| 100 dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_
Notes/769149-001.pdf |
| 101 dnl Cray's crayCC needs "-h std=c++11" |
| 102 for alternative in ${ax_cxx_compile_alternatives}; do |
| 103 for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${a
lternative}"; do |
| 104 cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) |
| 105 AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, |
| 106 $cachevar, |
| 107 [ac_save_CXX="$CXX" |
| 108 CXX="$CXX $switch" |
| 109 AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1
])], |
| 110 [eval $cachevar=yes], |
| 111 [eval $cachevar=no]) |
| 112 CXX="$ac_save_CXX"]) |
| 113 if eval test x\$$cachevar = xyes; then |
| 114 CXX="$CXX $switch" |
| 115 if test -n "$CXXCPP" ; then |
| 116 CXXCPP="$CXXCPP $switch" |
| 117 fi |
| 118 ac_success=yes |
| 119 break |
| 120 fi |
| 121 done |
| 122 if test x$ac_success = xyes; then |
| 123 break |
| 124 fi |
| 125 done |
| 126 fi]) |
| 127 AC_LANG_POP([C++]) |
| 128 if test x$ax_cxx_compile_cxx$1_required = xtrue; then |
| 129 if test x$ac_success = xno; then |
| 130 AC_MSG_ERROR([*** A compiler with support for C++$1 language features is r
equired.]) |
| 131 fi |
| 132 fi |
| 133 if test x$ac_success = xno; then |
| 134 HAVE_CXX$1=0 |
| 135 AC_MSG_NOTICE([No compiler with C++$1 support was found]) |
| 136 else |
| 137 HAVE_CXX$1=1 |
| 138 AC_DEFINE(HAVE_CXX$1,1, |
| 139 [define if the compiler supports basic C++$1 syntax]) |
| 140 fi |
| 141 AC_SUBST(HAVE_CXX$1) |
| 142 m4_if([$1], [17], [AC_MSG_WARN([C++17 is not yet standardized, so the checks m
ay change in incompatible ways anytime])]) |
| 143 ]) |
| 144 |
| 145 |
| 146 dnl Test body for checking C++11 support |
| 147 |
| 148 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11], |
| 149 _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 |
| 150 ) |
| 151 |
| 152 |
| 153 dnl Test body for checking C++14 support |
| 154 |
| 155 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14], |
| 156 _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 |
| 157 _AX_CXX_COMPILE_STDCXX_testbody_new_in_14 |
| 158 ) |
| 159 |
| 160 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_17], |
| 161 _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 |
| 162 _AX_CXX_COMPILE_STDCXX_testbody_new_in_14 |
| 163 _AX_CXX_COMPILE_STDCXX_testbody_new_in_17 |
| 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_separators |
| 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 |
| 578 |
| 579 dnl Tests for new features in C++17 |
| 580 |
| 581 m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_17], [[ |
| 582 |
| 583 // If the compiler admits that it is not ready for C++17, why torture it? |
| 584 // Hopefully, this will speed up the test. |
| 585 |
| 586 #ifndef __cplusplus |
| 587 |
| 588 #error "This is not a C++ compiler" |
| 589 |
| 590 #elif __cplusplus <= 201402L |
| 591 |
| 592 #error "This is not a C++17 compiler" |
| 593 |
| 594 #else |
| 595 |
| 596 #if defined(__clang__) |
| 597 #define REALLY_CLANG |
| 598 #else |
| 599 #if defined(__GNUC__) |
| 600 #define REALLY_GCC |
| 601 #endif |
| 602 #endif |
| 603 |
| 604 #include <initializer_list> |
| 605 #include <utility> |
| 606 #include <type_traits> |
| 607 |
| 608 namespace cxx17 |
| 609 { |
| 610 |
| 611 #if !defined(REALLY_CLANG) |
| 612 namespace test_constexpr_lambdas |
| 613 { |
| 614 |
| 615 // TODO: test it with clang++ from git |
| 616 |
| 617 constexpr int foo = [](){return 42;}(); |
| 618 |
| 619 } |
| 620 #endif // !defined(REALLY_CLANG) |
| 621 |
| 622 namespace test::nested_namespace::definitions |
| 623 { |
| 624 |
| 625 } |
| 626 |
| 627 namespace test_fold_expression |
| 628 { |
| 629 |
| 630 template<typename... Args> |
| 631 int multiply(Args... args) |
| 632 { |
| 633 return (args * ... * 1); |
| 634 } |
| 635 |
| 636 template<typename... Args> |
| 637 bool all(Args... args) |
| 638 { |
| 639 return (args && ...); |
| 640 } |
| 641 |
| 642 } |
| 643 |
| 644 namespace test_extended_static_assert |
| 645 { |
| 646 |
| 647 static_assert (true); |
| 648 |
| 649 } |
| 650 |
| 651 namespace test_auto_brace_init_list |
| 652 { |
| 653 |
| 654 auto foo = {5}; |
| 655 auto bar {5}; |
| 656 |
| 657 static_assert(std::is_same<std::initializer_list<int>, decltype(foo)>::value
); |
| 658 static_assert(std::is_same<int, decltype(bar)>::value); |
| 659 } |
| 660 |
| 661 namespace test_typename_in_template_template_parameter |
| 662 { |
| 663 |
| 664 template<template<typename> typename X> struct D; |
| 665 |
| 666 } |
| 667 |
| 668 namespace test_fallthrough_nodiscard_maybe_unused_attributes |
| 669 { |
| 670 |
| 671 int f1() |
| 672 { |
| 673 return 42; |
| 674 } |
| 675 |
| 676 [[nodiscard]] int f2() |
| 677 { |
| 678 [[maybe_unused]] auto unused = f1(); |
| 679 |
| 680 switch (f1()) |
| 681 { |
| 682 case 17: |
| 683 f1(); |
| 684 [[fallthrough]]; |
| 685 case 42: |
| 686 f1(); |
| 687 } |
| 688 return f1(); |
| 689 } |
| 690 |
| 691 } |
| 692 |
| 693 namespace test_extended_aggregate_initialization |
| 694 { |
| 695 |
| 696 struct base1 |
| 697 { |
| 698 int b1, b2 = 42; |
| 699 }; |
| 700 |
| 701 struct base2 |
| 702 { |
| 703 base2() { |
| 704 b3 = 42; |
| 705 } |
| 706 int b3; |
| 707 }; |
| 708 |
| 709 struct derived : base1, base2 |
| 710 { |
| 711 int d; |
| 712 }; |
| 713 |
| 714 derived d1 {{1, 2}, {}, 4}; // full initialization |
| 715 derived d2 {{}, {}, 4}; // value-initialized bases |
| 716 |
| 717 } |
| 718 |
| 719 namespace test_general_range_based_for_loop |
| 720 { |
| 721 |
| 722 struct iter |
| 723 { |
| 724 int i; |
| 725 |
| 726 int& operator* () |
| 727 { |
| 728 return i; |
| 729 } |
| 730 |
| 731 const int& operator* () const |
| 732 { |
| 733 return i; |
| 734 } |
| 735 |
| 736 iter& operator++() |
| 737 { |
| 738 ++i; |
| 739 return *this; |
| 740 } |
| 741 }; |
| 742 |
| 743 struct sentinel |
| 744 { |
| 745 int i; |
| 746 }; |
| 747 |
| 748 bool operator== (const iter& i, const sentinel& s) |
| 749 { |
| 750 return i.i == s.i; |
| 751 } |
| 752 |
| 753 bool operator!= (const iter& i, const sentinel& s) |
| 754 { |
| 755 return !(i == s); |
| 756 } |
| 757 |
| 758 struct range |
| 759 { |
| 760 iter begin() const |
| 761 { |
| 762 return {0}; |
| 763 } |
| 764 |
| 765 sentinel end() const |
| 766 { |
| 767 return {5}; |
| 768 } |
| 769 }; |
| 770 |
| 771 void f() |
| 772 { |
| 773 range r {}; |
| 774 |
| 775 for (auto i : r) |
| 776 { |
| 777 [[maybe_unused]] auto v = i; |
| 778 } |
| 779 } |
| 780 |
| 781 } |
| 782 |
| 783 namespace test_lambda_capture_asterisk_this_by_value |
| 784 { |
| 785 |
| 786 struct t |
| 787 { |
| 788 int i; |
| 789 int foo() |
| 790 { |
| 791 return [*this]() |
| 792 { |
| 793 return i; |
| 794 }(); |
| 795 } |
| 796 }; |
| 797 |
| 798 } |
| 799 |
| 800 namespace test_enum_class_construction |
| 801 { |
| 802 |
| 803 enum class byte : unsigned char |
| 804 {}; |
| 805 |
| 806 byte foo {42}; |
| 807 |
| 808 } |
| 809 |
| 810 namespace test_constexpr_if |
| 811 { |
| 812 |
| 813 template <bool cond> |
| 814 int f () |
| 815 { |
| 816 if constexpr(cond) |
| 817 { |
| 818 return 13; |
| 819 } |
| 820 else |
| 821 { |
| 822 return 42; |
| 823 } |
| 824 } |
| 825 |
| 826 } |
| 827 |
| 828 namespace test_selection_statement_with_initializer |
| 829 { |
| 830 |
| 831 int f() |
| 832 { |
| 833 return 13; |
| 834 } |
| 835 |
| 836 int f2() |
| 837 { |
| 838 if (auto i = f(); i > 0) |
| 839 { |
| 840 return 3; |
| 841 } |
| 842 |
| 843 switch (auto i = f(); i + 4) |
| 844 { |
| 845 case 17: |
| 846 return 2; |
| 847 |
| 848 default: |
| 849 return 1; |
| 850 } |
| 851 } |
| 852 |
| 853 } |
| 854 |
| 855 #if !defined(REALLY_CLANG) |
| 856 namespace test_template_argument_deduction_for_class_templates |
| 857 { |
| 858 |
| 859 // TODO: test it with clang++ from git |
| 860 |
| 861 template <typename T1, typename T2> |
| 862 struct pair |
| 863 { |
| 864 pair (T1 p1, T2 p2) |
| 865 : m1 {p1}, |
| 866 m2 {p2} |
| 867 {} |
| 868 |
| 869 T1 m1; |
| 870 T2 m2; |
| 871 }; |
| 872 |
| 873 void f() |
| 874 { |
| 875 [[maybe_unused]] auto p = pair{13, 42u}; |
| 876 } |
| 877 |
| 878 } |
| 879 #endif // !defined(REALLY_CLANG) |
| 880 |
| 881 namespace test_non_type_auto_template_parameters |
| 882 { |
| 883 |
| 884 template <auto n> |
| 885 struct B |
| 886 {}; |
| 887 |
| 888 B<5> b1; |
| 889 B<'a'> b2; |
| 890 |
| 891 } |
| 892 |
| 893 #if !defined(REALLY_CLANG) |
| 894 namespace test_structured_bindings |
| 895 { |
| 896 |
| 897 // TODO: test it with clang++ from git |
| 898 |
| 899 int arr[2] = { 1, 2 }; |
| 900 std::pair<int, int> pr = { 1, 2 }; |
| 901 |
| 902 auto f1() -> int(&)[2] |
| 903 { |
| 904 return arr; |
| 905 } |
| 906 |
| 907 auto f2() -> std::pair<int, int>& |
| 908 { |
| 909 return pr; |
| 910 } |
| 911 |
| 912 struct S |
| 913 { |
| 914 int x1 : 2; |
| 915 volatile double y1; |
| 916 }; |
| 917 |
| 918 S f3() |
| 919 { |
| 920 return {}; |
| 921 } |
| 922 |
| 923 auto [ x1, y1 ] = f1(); |
| 924 auto& [ xr1, yr1 ] = f1(); |
| 925 auto [ x2, y2 ] = f2(); |
| 926 auto& [ xr2, yr2 ] = f2(); |
| 927 const auto [ x3, y3 ] = f3(); |
| 928 |
| 929 } |
| 930 #endif // !defined(REALLY_CLANG) |
| 931 |
| 932 #if !defined(REALLY_CLANG) |
| 933 namespace test_exception_spec_type_system |
| 934 { |
| 935 |
| 936 // TODO: test it with clang++ from git |
| 937 |
| 938 struct Good {}; |
| 939 struct Bad {}; |
| 940 |
| 941 void g1() noexcept; |
| 942 void g2(); |
| 943 |
| 944 template<typename T> |
| 945 Bad |
| 946 f(T*, T*); |
| 947 |
| 948 template<typename T1, typename T2> |
| 949 Good |
| 950 f(T1*, T2*); |
| 951 |
| 952 static_assert (std::is_same_v<Good, decltype(f(g1, g2))>); |
| 953 |
| 954 } |
| 955 #endif // !defined(REALLY_CLANG) |
| 956 |
| 957 namespace test_inline_variables |
| 958 { |
| 959 |
| 960 template<class T> void f(T) |
| 961 {} |
| 962 |
| 963 template<class T> inline T g(T) |
| 964 { |
| 965 return T{}; |
| 966 } |
| 967 |
| 968 template<> inline void f<>(int) |
| 969 {} |
| 970 |
| 971 template<> int g<>(int) |
| 972 { |
| 973 return 5; |
| 974 } |
| 975 |
| 976 } |
| 977 |
| 978 } // namespace cxx17 |
| 979 |
| 980 #endif // __cplusplus <= 201402L |
| 981 |
| 982 ]]) |
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