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1 | # =========================================================================== |
2 | # https://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 | # SPDX-License-Identifier: FSFAP | |
31 | # | |
32 | # Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com> | |
33 | # Copyright (c) 2012 Zack Weinberg <zackw@panix.com> | |
34 | # Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu> | |
35 | # Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com> | |
36 | # Copyright (c) 2015 Paul Norman <penorman@mac.com> | |
37 | # Copyright (c) 2015 Moritz Klammler <moritz@klammler.eu> | |
38 | # Copyright (c) 2016, 2018 Krzesimir Nowak <qdlacz@gmail.com> | |
39 | # Copyright (c) 2019 Enji Cooper <yaneurabeya@gmail.com> | |
40 | # | |
41 | # Copying and distribution of this file, with or without modification, are | |
42 | # permitted in any medium without royalty provided the copyright notice | |
43 | # and this notice are preserved. This file is offered as-is, without any | |
44 | # warranty. | |
45 | ||
46 | #serial 11 | |
47 | ||
48 | dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro | |
49 | dnl (serial version number 13). | |
50 | ||
51 | AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl | |
52 | m4_if([$1], [11], [ax_cxx_compile_alternatives="11 0x"], | |
53 | [$1], [14], [ax_cxx_compile_alternatives="14 1y"], | |
54 | [$1], [17], [ax_cxx_compile_alternatives="17 1z"], | |
55 | [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl | |
56 | m4_if([$2], [], [], | |
57 | [$2], [ext], [], | |
58 | [$2], [noext], [], | |
59 | [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl | |
60 | m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true], | |
61 | [$3], [mandatory], [ax_cxx_compile_cxx$1_required=true], | |
62 | [$3], [optional], [ax_cxx_compile_cxx$1_required=false], | |
63 | [m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])]) | |
64 | AC_LANG_PUSH([C++])dnl | |
65 | ac_success=no | |
66 | ||
67 | m4_if([$2], [noext], [], [dnl | |
68 | if test x$ac_success = xno; then | |
69 | for alternative in ${ax_cxx_compile_alternatives}; do | |
70 | switch="-std=gnu++${alternative}" | |
71 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) | |
72 | AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, | |
73 | $cachevar, | |
74 | [ac_save_CXX="$CXX" | |
75 | CXX="$CXX $switch" | |
76 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], | |
77 | [eval $cachevar=yes], | |
78 | [eval $cachevar=no]) | |
79 | CXX="$ac_save_CXX"]) | |
80 | if eval test x\$$cachevar = xyes; then | |
81 | CXX="$CXX $switch" | |
82 | if test -n "$CXXCPP" ; then | |
83 | CXXCPP="$CXXCPP $switch" | |
84 | fi | |
85 | ac_success=yes | |
86 | break | |
87 | fi | |
88 | done | |
89 | fi]) | |
90 | ||
91 | m4_if([$2], [ext], [], [dnl | |
92 | if test x$ac_success = xno; then | |
93 | dnl HP's aCC needs +std=c++11 according to: | |
94 | dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf | |
95 | dnl Cray's crayCC needs "-h std=c++11" | |
96 | for alternative in ${ax_cxx_compile_alternatives}; do | |
97 | for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${alternative}"; do | |
98 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) | |
99 | AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, | |
100 | $cachevar, | |
101 | [ac_save_CXX="$CXX" | |
102 | CXX="$CXX $switch" | |
103 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], | |
104 | [eval $cachevar=yes], | |
105 | [eval $cachevar=no]) | |
106 | CXX="$ac_save_CXX"]) | |
107 | if eval test x\$$cachevar = xyes; then | |
108 | CXX="$CXX $switch" | |
109 | if test -n "$CXXCPP" ; then | |
110 | CXXCPP="$CXXCPP $switch" | |
111 | fi | |
112 | ac_success=yes | |
113 | break | |
114 | fi | |
115 | done | |
116 | if test x$ac_success = xyes; then | |
117 | break | |
118 | fi | |
119 | done | |
120 | fi]) | |
121 | AC_LANG_POP([C++]) | |
122 | if test x$ax_cxx_compile_cxx$1_required = xtrue; then | |
123 | if test x$ac_success = xno; then | |
124 | AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.]) | |
125 | fi | |
126 | fi | |
127 | if test x$ac_success = xno; then | |
128 | HAVE_CXX$1=0 | |
129 | AC_MSG_NOTICE([No compiler with C++$1 support was found]) | |
130 | else | |
131 | HAVE_CXX$1=1 | |
132 | AC_DEFINE(HAVE_CXX$1,1, | |
133 | [define if the compiler supports basic C++$1 syntax]) | |
134 | fi | |
135 | AC_SUBST(HAVE_CXX$1) | |
136 | ]) | |
137 | ||
138 | ||
139 | dnl Test body for checking C++11 support | |
140 | ||
141 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11], | |
142 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 | |
143 | ) | |
144 | ||
145 | ||
146 | dnl Test body for checking C++14 support | |
147 | ||
148 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14], | |
149 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 | |
150 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_14 | |
151 | ) | |
152 | ||
153 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_17], | |
154 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 | |
155 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_14 | |
156 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_17 | |
157 | ) | |
158 | ||
159 | dnl Tests for new features in C++11 | |
160 | ||
161 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[ | |
162 | ||
163 | // If the compiler admits that it is not ready for C++11, why torture it? | |
164 | // Hopefully, this will speed up the test. | |
165 | ||
166 | #ifndef __cplusplus | |
167 | ||
168 | #error "This is not a C++ compiler" | |
169 | ||
170 | #elif __cplusplus < 201103L | |
171 | ||
172 | #error "This is not a C++11 compiler" | |
173 | ||
174 | #else | |
175 | ||
176 | namespace cxx11 | |
177 | { | |
178 | ||
179 | namespace test_static_assert | |
180 | { | |
181 | ||
182 | template <typename T> | |
183 | struct check | |
184 | { | |
185 | static_assert(sizeof(int) <= sizeof(T), "not big enough"); | |
186 | }; | |
187 | ||
188 | } | |
189 | ||
190 | namespace test_final_override | |
191 | { | |
192 | ||
193 | struct Base | |
194 | { | |
195 | virtual ~Base() {} | |
196 | virtual void f() {} | |
197 | }; | |
198 | ||
199 | struct Derived : public Base | |
200 | { | |
201 | virtual ~Derived() override {} | |
202 | virtual void f() override {} | |
203 | }; | |
204 | ||
205 | } | |
206 | ||
207 | namespace test_double_right_angle_brackets | |
208 | { | |
209 | ||
210 | template < typename T > | |
211 | struct check {}; | |
212 | ||
213 | typedef check<void> single_type; | |
214 | typedef check<check<void>> double_type; | |
215 | typedef check<check<check<void>>> triple_type; | |
216 | typedef check<check<check<check<void>>>> quadruple_type; | |
217 | ||
218 | } | |
219 | ||
220 | namespace test_decltype | |
221 | { | |
222 | ||
223 | int | |
224 | f() | |
225 | { | |
226 | int a = 1; | |
227 | decltype(a) b = 2; | |
228 | return a + b; | |
229 | } | |
230 | ||
231 | } | |
232 | ||
233 | namespace test_type_deduction | |
234 | { | |
235 | ||
236 | template < typename T1, typename T2 > | |
237 | struct is_same | |
238 | { | |
239 | static const bool value = false; | |
240 | }; | |
241 | ||
242 | template < typename T > | |
243 | struct is_same<T, T> | |
244 | { | |
245 | static const bool value = true; | |
246 | }; | |
247 | ||
248 | template < typename T1, typename T2 > | |
249 | auto | |
250 | add(T1 a1, T2 a2) -> decltype(a1 + a2) | |
251 | { | |
252 | return a1 + a2; | |
253 | } | |
254 | ||
255 | int | |
256 | test(const int c, volatile int v) | |
257 | { | |
258 | static_assert(is_same<int, decltype(0)>::value == true, ""); | |
259 | static_assert(is_same<int, decltype(c)>::value == false, ""); | |
260 | static_assert(is_same<int, decltype(v)>::value == false, ""); | |
261 | auto ac = c; | |
262 | auto av = v; | |
263 | auto sumi = ac + av + 'x'; | |
264 | auto sumf = ac + av + 1.0; | |
265 | static_assert(is_same<int, decltype(ac)>::value == true, ""); | |
266 | static_assert(is_same<int, decltype(av)>::value == true, ""); | |
267 | static_assert(is_same<int, decltype(sumi)>::value == true, ""); | |
268 | static_assert(is_same<int, decltype(sumf)>::value == false, ""); | |
269 | static_assert(is_same<int, decltype(add(c, v))>::value == true, ""); | |
270 | return (sumf > 0.0) ? sumi : add(c, v); | |
271 | } | |
272 | ||
273 | } | |
274 | ||
275 | namespace test_noexcept | |
276 | { | |
277 | ||
278 | int f() { return 0; } | |
279 | int g() noexcept { return 0; } | |
280 | ||
281 | static_assert(noexcept(f()) == false, ""); | |
282 | static_assert(noexcept(g()) == true, ""); | |
283 | ||
284 | } | |
285 | ||
286 | namespace test_constexpr | |
287 | { | |
288 | ||
289 | template < typename CharT > | |
290 | unsigned long constexpr | |
291 | strlen_c_r(const CharT *const s, const unsigned long acc) noexcept | |
292 | { | |
293 | return *s ? strlen_c_r(s + 1, acc + 1) : acc; | |
294 | } | |
295 | ||
296 | template < typename CharT > | |
297 | unsigned long constexpr | |
298 | strlen_c(const CharT *const s) noexcept | |
299 | { | |
300 | return strlen_c_r(s, 0UL); | |
301 | } | |
302 | ||
303 | static_assert(strlen_c("") == 0UL, ""); | |
304 | static_assert(strlen_c("1") == 1UL, ""); | |
305 | static_assert(strlen_c("example") == 7UL, ""); | |
306 | static_assert(strlen_c("another\0example") == 7UL, ""); | |
307 | ||
308 | } | |
309 | ||
310 | namespace test_rvalue_references | |
311 | { | |
312 | ||
313 | template < int N > | |
314 | struct answer | |
315 | { | |
316 | static constexpr int value = N; | |
317 | }; | |
318 | ||
319 | answer<1> f(int&) { return answer<1>(); } | |
320 | answer<2> f(const int&) { return answer<2>(); } | |
321 | answer<3> f(int&&) { return answer<3>(); } | |
322 | ||
323 | void | |
324 | test() | |
325 | { | |
326 | int i = 0; | |
327 | const int c = 0; | |
328 | static_assert(decltype(f(i))::value == 1, ""); | |
329 | static_assert(decltype(f(c))::value == 2, ""); | |
330 | static_assert(decltype(f(0))::value == 3, ""); | |
331 | } | |
332 | ||
333 | } | |
334 | ||
335 | namespace test_uniform_initialization | |
336 | { | |
337 | ||
338 | struct test | |
339 | { | |
340 | static const int zero {}; | |
341 | static const int one {1}; | |
342 | }; | |
343 | ||
344 | static_assert(test::zero == 0, ""); | |
345 | static_assert(test::one == 1, ""); | |
346 | ||
347 | } | |
348 | ||
349 | namespace test_lambdas | |
350 | { | |
351 | ||
352 | void | |
353 | test1() | |
354 | { | |
355 | auto lambda1 = [](){}; | |
356 | auto lambda2 = lambda1; | |
357 | lambda1(); | |
358 | lambda2(); | |
359 | } | |
360 | ||
361 | int | |
362 | test2() | |
363 | { | |
364 | auto a = [](int i, int j){ return i + j; }(1, 2); | |
365 | auto b = []() -> int { return '0'; }(); | |
366 | auto c = [=](){ return a + b; }(); | |
367 | auto d = [&](){ return c; }(); | |
368 | auto e = [a, &b](int x) mutable { | |
369 | const auto identity = [](int y){ return y; }; | |
370 | for (auto i = 0; i < a; ++i) | |
371 | a += b--; | |
372 | return x + identity(a + b); | |
373 | }(0); | |
374 | return a + b + c + d + e; | |
375 | } | |
376 | ||
377 | int | |
378 | test3() | |
379 | { | |
380 | const auto nullary = [](){ return 0; }; | |
381 | const auto unary = [](int x){ return x; }; | |
382 | using nullary_t = decltype(nullary); | |
383 | using unary_t = decltype(unary); | |
384 | const auto higher1st = [](nullary_t f){ return f(); }; | |
385 | const auto higher2nd = [unary](nullary_t f1){ | |
386 | return [unary, f1](unary_t f2){ return f2(unary(f1())); }; | |
387 | }; | |
388 | return higher1st(nullary) + higher2nd(nullary)(unary); | |
389 | } | |
390 | ||
391 | } | |
392 | ||
393 | namespace test_variadic_templates | |
394 | { | |
395 | ||
396 | template <int...> | |
397 | struct sum; | |
398 | ||
399 | template <int N0, int... N1toN> | |
400 | struct sum<N0, N1toN...> | |
401 | { | |
402 | static constexpr auto value = N0 + sum<N1toN...>::value; | |
403 | }; | |
404 | ||
405 | template <> | |
406 | struct sum<> | |
407 | { | |
408 | static constexpr auto value = 0; | |
409 | }; | |
410 | ||
411 | static_assert(sum<>::value == 0, ""); | |
412 | static_assert(sum<1>::value == 1, ""); | |
413 | static_assert(sum<23>::value == 23, ""); | |
414 | static_assert(sum<1, 2>::value == 3, ""); | |
415 | static_assert(sum<5, 5, 11>::value == 21, ""); | |
416 | static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, ""); | |
417 | ||
418 | } | |
419 | ||
420 | // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae | |
421 | // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function | |
422 | // because of this. | |
423 | namespace test_template_alias_sfinae | |
424 | { | |
425 | ||
426 | struct foo {}; | |
427 | ||
428 | template<typename T> | |
429 | using member = typename T::member_type; | |
430 | ||
431 | template<typename T> | |
432 | void func(...) {} | |
433 | ||
434 | template<typename T> | |
435 | void func(member<T>*) {} | |
436 | ||
437 | void test(); | |
438 | ||
439 | void test() { func<foo>(0); } | |
440 | ||
441 | } | |
442 | ||
443 | } // namespace cxx11 | |
444 | ||
445 | #endif // __cplusplus >= 201103L | |
446 | ||
447 | ]]) | |
448 | ||
449 | ||
450 | dnl Tests for new features in C++14 | |
451 | ||
452 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[ | |
453 | ||
454 | // If the compiler admits that it is not ready for C++14, why torture it? | |
455 | // Hopefully, this will speed up the test. | |
456 | ||
457 | #ifndef __cplusplus | |
458 | ||
459 | #error "This is not a C++ compiler" | |
460 | ||
461 | #elif __cplusplus < 201402L | |
462 | ||
463 | #error "This is not a C++14 compiler" | |
464 | ||
465 | #else | |
466 | ||
467 | namespace cxx14 | |
468 | { | |
469 | ||
470 | namespace test_polymorphic_lambdas | |
471 | { | |
472 | ||
473 | int | |
474 | test() | |
475 | { | |
476 | const auto lambda = [](auto&&... args){ | |
477 | const auto istiny = [](auto x){ | |
478 | return (sizeof(x) == 1UL) ? 1 : 0; | |
479 | }; | |
480 | const int aretiny[] = { istiny(args)... }; | |
481 | return aretiny[0]; | |
482 | }; | |
483 | return lambda(1, 1L, 1.0f, '1'); | |
484 | } | |
485 | ||
486 | } | |
487 | ||
488 | namespace test_binary_literals | |
489 | { | |
490 | ||
491 | constexpr auto ivii = 0b0000000000101010; | |
492 | static_assert(ivii == 42, "wrong value"); | |
493 | ||
494 | } | |
495 | ||
496 | namespace test_generalized_constexpr | |
497 | { | |
498 | ||
499 | template < typename CharT > | |
500 | constexpr unsigned long | |
501 | strlen_c(const CharT *const s) noexcept | |
502 | { | |
503 | auto length = 0UL; | |
504 | for (auto p = s; *p; ++p) | |
505 | ++length; | |
506 | return length; | |
507 | } | |
508 | ||
509 | static_assert(strlen_c("") == 0UL, ""); | |
510 | static_assert(strlen_c("x") == 1UL, ""); | |
511 | static_assert(strlen_c("test") == 4UL, ""); | |
512 | static_assert(strlen_c("another\0test") == 7UL, ""); | |
513 | ||
514 | } | |
515 | ||
516 | namespace test_lambda_init_capture | |
517 | { | |
518 | ||
519 | int | |
520 | test() | |
521 | { | |
522 | auto x = 0; | |
523 | const auto lambda1 = [a = x](int b){ return a + b; }; | |
524 | const auto lambda2 = [a = lambda1(x)](){ return a; }; | |
525 | return lambda2(); | |
526 | } | |
527 | ||
528 | } | |
529 | ||
530 | namespace test_digit_separators | |
531 | { | |
532 | ||
533 | constexpr auto ten_million = 100'000'000; | |
534 | static_assert(ten_million == 100000000, ""); | |
535 | ||
536 | } | |
537 | ||
538 | namespace test_return_type_deduction | |
539 | { | |
540 | ||
541 | auto f(int& x) { return x; } | |
542 | decltype(auto) g(int& x) { return x; } | |
543 | ||
544 | template < typename T1, typename T2 > | |
545 | struct is_same | |
546 | { | |
547 | static constexpr auto value = false; | |
548 | }; | |
549 | ||
550 | template < typename T > | |
551 | struct is_same<T, T> | |
552 | { | |
553 | static constexpr auto value = true; | |
554 | }; | |
555 | ||
556 | int | |
557 | test() | |
558 | { | |
559 | auto x = 0; | |
560 | static_assert(is_same<int, decltype(f(x))>::value, ""); | |
561 | static_assert(is_same<int&, decltype(g(x))>::value, ""); | |
562 | return x; | |
563 | } | |
564 | ||
565 | } | |
566 | ||
567 | } // namespace cxx14 | |
568 | ||
569 | #endif // __cplusplus >= 201402L | |
570 | ||
571 | ]]) | |
572 | ||
573 | ||
574 | dnl Tests for new features in C++17 | |
575 | ||
576 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_17], [[ | |
577 | ||
578 | // If the compiler admits that it is not ready for C++17, why torture it? | |
579 | // Hopefully, this will speed up the test. | |
580 | ||
581 | #ifndef __cplusplus | |
582 | ||
583 | #error "This is not a C++ compiler" | |
584 | ||
585 | #elif __cplusplus < 201703L | |
586 | ||
587 | #error "This is not a C++17 compiler" | |
588 | ||
589 | #else | |
590 | ||
591 | #include <initializer_list> | |
592 | #include <utility> | |
593 | #include <type_traits> | |
594 | ||
595 | namespace cxx17 | |
596 | { | |
597 | ||
598 | namespace test_constexpr_lambdas | |
599 | { | |
600 | ||
601 | constexpr int foo = [](){return 42;}(); | |
602 | ||
603 | } | |
604 | ||
605 | namespace test::nested_namespace::definitions | |
606 | { | |
607 | ||
608 | } | |
609 | ||
610 | namespace test_fold_expression | |
611 | { | |
612 | ||
613 | template<typename... Args> | |
614 | int multiply(Args... args) | |
615 | { | |
616 | return (args * ... * 1); | |
617 | } | |
618 | ||
619 | template<typename... Args> | |
620 | bool all(Args... args) | |
621 | { | |
622 | return (args && ...); | |
623 | } | |
624 | ||
625 | } | |
626 | ||
627 | namespace test_extended_static_assert | |
628 | { | |
629 | ||
630 | static_assert (true); | |
631 | ||
632 | } | |
633 | ||
634 | namespace test_auto_brace_init_list | |
635 | { | |
636 | ||
637 | auto foo = {5}; | |
638 | auto bar {5}; | |
639 | ||
640 | static_assert(std::is_same<std::initializer_list<int>, decltype(foo)>::value); | |
641 | static_assert(std::is_same<int, decltype(bar)>::value); | |
642 | } | |
643 | ||
644 | namespace test_typename_in_template_template_parameter | |
645 | { | |
646 | ||
647 | template<template<typename> typename X> struct D; | |
648 | ||
649 | } | |
650 | ||
651 | namespace test_fallthrough_nodiscard_maybe_unused_attributes | |
652 | { | |
653 | ||
654 | int f1() | |
655 | { | |
656 | return 42; | |
657 | } | |
658 | ||
659 | [[nodiscard]] int f2() | |
660 | { | |
661 | [[maybe_unused]] auto unused = f1(); | |
662 | ||
663 | switch (f1()) | |
664 | { | |
665 | case 17: | |
666 | f1(); | |
667 | [[fallthrough]]; | |
668 | case 42: | |
669 | f1(); | |
670 | } | |
671 | return f1(); | |
672 | } | |
673 | ||
674 | } | |
675 | ||
676 | namespace test_extended_aggregate_initialization | |
677 | { | |
678 | ||
679 | struct base1 | |
680 | { | |
681 | int b1, b2 = 42; | |
682 | }; | |
683 | ||
684 | struct base2 | |
685 | { | |
686 | base2() { | |
687 | b3 = 42; | |
688 | } | |
689 | int b3; | |
690 | }; | |
691 | ||
692 | struct derived : base1, base2 | |
693 | { | |
694 | int d; | |
695 | }; | |
696 | ||
697 | derived d1 {{1, 2}, {}, 4}; // full initialization | |
698 | derived d2 {{}, {}, 4}; // value-initialized bases | |
699 | ||
700 | } | |
701 | ||
702 | namespace test_general_range_based_for_loop | |
703 | { | |
704 | ||
705 | struct iter | |
706 | { | |
707 | int i; | |
708 | ||
709 | int& operator* () | |
710 | { | |
711 | return i; | |
712 | } | |
713 | ||
714 | const int& operator* () const | |
715 | { | |
716 | return i; | |
717 | } | |
718 | ||
719 | iter& operator++() | |
720 | { | |
721 | ++i; | |
722 | return *this; | |
723 | } | |
724 | }; | |
725 | ||
726 | struct sentinel | |
727 | { | |
728 | int i; | |
729 | }; | |
730 | ||
731 | bool operator== (const iter& i, const sentinel& s) | |
732 | { | |
733 | return i.i == s.i; | |
734 | } | |
735 | ||
736 | bool operator!= (const iter& i, const sentinel& s) | |
737 | { | |
738 | return !(i == s); | |
739 | } | |
740 | ||
741 | struct range | |
742 | { | |
743 | iter begin() const | |
744 | { | |
745 | return {0}; | |
746 | } | |
747 | ||
748 | sentinel end() const | |
749 | { | |
750 | return {5}; | |
751 | } | |
752 | }; | |
753 | ||
754 | void f() | |
755 | { | |
756 | range r {}; | |
757 | ||
758 | for (auto i : r) | |
759 | { | |
760 | [[maybe_unused]] auto v = i; | |
761 | } | |
762 | } | |
763 | ||
764 | } | |
765 | ||
766 | namespace test_lambda_capture_asterisk_this_by_value | |
767 | { | |
768 | ||
769 | struct t | |
770 | { | |
771 | int i; | |
772 | int foo() | |
773 | { | |
774 | return [*this]() | |
775 | { | |
776 | return i; | |
777 | }(); | |
778 | } | |
779 | }; | |
780 | ||
781 | } | |
782 | ||
783 | namespace test_enum_class_construction | |
784 | { | |
785 | ||
786 | enum class byte : unsigned char | |
787 | {}; | |
788 | ||
789 | byte foo {42}; | |
790 | ||
791 | } | |
792 | ||
793 | namespace test_constexpr_if | |
794 | { | |
795 | ||
796 | template <bool cond> | |
797 | int f () | |
798 | { | |
799 | if constexpr(cond) | |
800 | { | |
801 | return 13; | |
802 | } | |
803 | else | |
804 | { | |
805 | return 42; | |
806 | } | |
807 | } | |
808 | ||
809 | } | |
810 | ||
811 | namespace test_selection_statement_with_initializer | |
812 | { | |
813 | ||
814 | int f() | |
815 | { | |
816 | return 13; | |
817 | } | |
818 | ||
819 | int f2() | |
820 | { | |
821 | if (auto i = f(); i > 0) | |
822 | { | |
823 | return 3; | |
824 | } | |
825 | ||
826 | switch (auto i = f(); i + 4) | |
827 | { | |
828 | case 17: | |
829 | return 2; | |
830 | ||
831 | default: | |
832 | return 1; | |
833 | } | |
834 | } | |
835 | ||
836 | } | |
837 | ||
838 | namespace test_template_argument_deduction_for_class_templates | |
839 | { | |
840 | ||
841 | template <typename T1, typename T2> | |
842 | struct pair | |
843 | { | |
844 | pair (T1 p1, T2 p2) | |
845 | : m1 {p1}, | |
846 | m2 {p2} | |
847 | {} | |
848 | ||
849 | T1 m1; | |
850 | T2 m2; | |
851 | }; | |
852 | ||
853 | void f() | |
854 | { | |
855 | [[maybe_unused]] auto p = pair{13, 42u}; | |
856 | } | |
857 | ||
858 | } | |
859 | ||
860 | namespace test_non_type_auto_template_parameters | |
861 | { | |
862 | ||
863 | template <auto n> | |
864 | struct B | |
865 | {}; | |
866 | ||
867 | B<5> b1; | |
868 | B<'a'> b2; | |
869 | ||
870 | } | |
871 | ||
872 | namespace test_structured_bindings | |
873 | { | |
874 | ||
875 | int arr[2] = { 1, 2 }; | |
876 | std::pair<int, int> pr = { 1, 2 }; | |
877 | ||
878 | auto f1() -> int(&)[2] | |
879 | { | |
880 | return arr; | |
881 | } | |
882 | ||
883 | auto f2() -> std::pair<int, int>& | |
884 | { | |
885 | return pr; | |
886 | } | |
887 | ||
888 | struct S | |
889 | { | |
890 | int x1 : 2; | |
891 | volatile double y1; | |
892 | }; | |
893 | ||
894 | S f3() | |
895 | { | |
896 | return {}; | |
897 | } | |
898 | ||
899 | auto [ x1, y1 ] = f1(); | |
900 | auto& [ xr1, yr1 ] = f1(); | |
901 | auto [ x2, y2 ] = f2(); | |
902 | auto& [ xr2, yr2 ] = f2(); | |
903 | const auto [ x3, y3 ] = f3(); | |
904 | ||
905 | } | |
906 | ||
907 | namespace test_exception_spec_type_system | |
908 | { | |
909 | ||
910 | struct Good {}; | |
911 | struct Bad {}; | |
912 | ||
913 | void g1() noexcept; | |
914 | void g2(); | |
915 | ||
916 | template<typename T> | |
917 | Bad | |
918 | f(T*, T*); | |
919 | ||
920 | template<typename T1, typename T2> | |
921 | Good | |
922 | f(T1*, T2*); | |
923 | ||
924 | static_assert (std::is_same_v<Good, decltype(f(g1, g2))>); | |
925 | ||
926 | } | |
927 | ||
928 | namespace test_inline_variables | |
929 | { | |
930 | ||
931 | template<class T> void f(T) | |
932 | {} | |
933 | ||
934 | template<class T> inline T g(T) | |
935 | { | |
936 | return T{}; | |
937 | } | |
938 | ||
939 | template<> inline void f<>(int) | |
940 | {} | |
941 | ||
942 | template<> int g<>(int) | |
943 | { | |
944 | return 5; | |
945 | } | |
946 | ||
947 | } | |
948 | ||
949 | } // namespace cxx17 | |
950 | ||
951 | #endif // __cplusplus < 201703L | |
952 | ||
953 | ]]) |