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