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1 | # SPDX-License-Identifier: FSFAP |
2 | # | |
15b385c8 MD |
3 | # =========================================================================== |
4 | # https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html | |
5 | # =========================================================================== | |
6 | # | |
7 | # SYNOPSIS | |
8 | # | |
9 | # AX_CXX_COMPILE_STDCXX(VERSION, [ext|noext], [mandatory|optional]) | |
10 | # | |
11 | # DESCRIPTION | |
12 | # | |
13 | # Check for baseline language coverage in the compiler for the specified | |
14 | # version of the C++ standard. If necessary, add switches to CXX and | |
e03d7c66 MJ |
15 | # CXXCPP to enable support. VERSION may be '11', '14', '17', or '20' for |
16 | # the respective C++ standard version. | |
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17 | # |
18 | # The second argument, if specified, indicates whether you insist on an | |
19 | # extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g. | |
20 | # -std=c++11). If neither is specified, you get whatever works, with | |
e03d7c66 | 21 | # preference for no added switch, and then for an extended mode. |
15b385c8 MD |
22 | # |
23 | # The third argument, if specified 'mandatory' or if left unspecified, | |
24 | # indicates that baseline support for the specified C++ standard is | |
25 | # required and that the macro should error out if no mode with that | |
26 | # support is found. If specified 'optional', then configuration proceeds | |
27 | # regardless, after defining HAVE_CXX${VERSION} if and only if a | |
28 | # supporting mode is found. | |
29 | # | |
30 | # LICENSE | |
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> | |
e03d7c66 MJ |
40 | # Copyright (c) 2020 Jason Merrill <jason@redhat.com> |
41 | # Copyright (c) 2021 Jörn Heusipp <osmanx@problemloesungsmaschine.de> | |
15b385c8 MD |
42 | # |
43 | # Copying and distribution of this file, with or without modification, are | |
44 | # permitted in any medium without royalty provided the copyright notice | |
45 | # and this notice are preserved. This file is offered as-is, without any | |
46 | # warranty. | |
47 | ||
e03d7c66 | 48 | #serial 18 |
15b385c8 MD |
49 | |
50 | dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro | |
51 | dnl (serial version number 13). | |
52 | ||
53 | AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl | |
54 | m4_if([$1], [11], [ax_cxx_compile_alternatives="11 0x"], | |
55 | [$1], [14], [ax_cxx_compile_alternatives="14 1y"], | |
56 | [$1], [17], [ax_cxx_compile_alternatives="17 1z"], | |
e03d7c66 | 57 | [$1], [20], [ax_cxx_compile_alternatives="20"], |
15b385c8 MD |
58 | [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl |
59 | m4_if([$2], [], [], | |
60 | [$2], [ext], [], | |
61 | [$2], [noext], [], | |
62 | [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl | |
63 | m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true], | |
64 | [$3], [mandatory], [ax_cxx_compile_cxx$1_required=true], | |
65 | [$3], [optional], [ax_cxx_compile_cxx$1_required=false], | |
66 | [m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])]) | |
67 | AC_LANG_PUSH([C++])dnl | |
68 | ac_success=no | |
69 | ||
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70 | m4_if([$2], [], [dnl |
71 | AC_CACHE_CHECK(whether $CXX supports C++$1 features by default, | |
72 | ax_cv_cxx_compile_cxx$1, | |
73 | [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], | |
74 | [ax_cv_cxx_compile_cxx$1=yes], | |
75 | [ax_cv_cxx_compile_cxx$1=no])]) | |
76 | if test x$ax_cv_cxx_compile_cxx$1 = xyes; then | |
77 | ac_success=yes | |
78 | fi]) | |
79 | ||
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80 | m4_if([$2], [noext], [], [dnl |
81 | if test x$ac_success = xno; then | |
82 | for alternative in ${ax_cxx_compile_alternatives}; do | |
83 | switch="-std=gnu++${alternative}" | |
84 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) | |
85 | AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, | |
86 | $cachevar, | |
87 | [ac_save_CXX="$CXX" | |
88 | CXX="$CXX $switch" | |
89 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], | |
90 | [eval $cachevar=yes], | |
91 | [eval $cachevar=no]) | |
92 | CXX="$ac_save_CXX"]) | |
93 | if eval test x\$$cachevar = xyes; then | |
94 | CXX="$CXX $switch" | |
95 | if test -n "$CXXCPP" ; then | |
96 | CXXCPP="$CXXCPP $switch" | |
97 | fi | |
98 | ac_success=yes | |
99 | break | |
100 | fi | |
101 | done | |
102 | fi]) | |
103 | ||
104 | m4_if([$2], [ext], [], [dnl | |
105 | if test x$ac_success = xno; then | |
106 | dnl HP's aCC needs +std=c++11 according to: | |
107 | dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf | |
108 | dnl Cray's crayCC needs "-h std=c++11" | |
e03d7c66 | 109 | dnl MSVC needs -std:c++NN for C++17 and later (default is C++14) |
15b385c8 | 110 | for alternative in ${ax_cxx_compile_alternatives}; do |
e03d7c66 MJ |
111 | for switch in -std=c++${alternative} +std=c++${alternative} "-h std=c++${alternative}" MSVC; do |
112 | if test x"$switch" = xMSVC; then | |
113 | dnl AS_TR_SH maps both `:` and `=` to `_` so -std:c++17 would collide | |
114 | dnl with -std=c++17. We suffix the cache variable name with _MSVC to | |
115 | dnl avoid this. | |
116 | switch=-std:c++${alternative} | |
117 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_${switch}_MSVC]) | |
118 | else | |
119 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) | |
120 | fi | |
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121 | AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, |
122 | $cachevar, | |
123 | [ac_save_CXX="$CXX" | |
124 | CXX="$CXX $switch" | |
125 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], | |
126 | [eval $cachevar=yes], | |
127 | [eval $cachevar=no]) | |
128 | CXX="$ac_save_CXX"]) | |
129 | if eval test x\$$cachevar = xyes; then | |
130 | CXX="$CXX $switch" | |
131 | if test -n "$CXXCPP" ; then | |
132 | CXXCPP="$CXXCPP $switch" | |
133 | fi | |
134 | ac_success=yes | |
135 | break | |
136 | fi | |
137 | done | |
138 | if test x$ac_success = xyes; then | |
139 | break | |
140 | fi | |
141 | done | |
142 | fi]) | |
143 | AC_LANG_POP([C++]) | |
144 | if test x$ax_cxx_compile_cxx$1_required = xtrue; then | |
145 | if test x$ac_success = xno; then | |
146 | AC_MSG_ERROR([*** A compiler with support for C++$1 language features is required.]) | |
147 | fi | |
148 | fi | |
149 | if test x$ac_success = xno; then | |
150 | HAVE_CXX$1=0 | |
151 | AC_MSG_NOTICE([No compiler with C++$1 support was found]) | |
152 | else | |
153 | HAVE_CXX$1=1 | |
154 | AC_DEFINE(HAVE_CXX$1,1, | |
155 | [define if the compiler supports basic C++$1 syntax]) | |
156 | fi | |
157 | AC_SUBST(HAVE_CXX$1) | |
158 | ]) | |
159 | ||
160 | ||
161 | dnl Test body for checking C++11 support | |
162 | ||
163 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_11], | |
164 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 | |
165 | ) | |
166 | ||
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167 | dnl Test body for checking C++14 support |
168 | ||
169 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_14], | |
170 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 | |
171 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_14 | |
172 | ) | |
173 | ||
e03d7c66 MJ |
174 | dnl Test body for checking C++17 support |
175 | ||
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176 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_17], |
177 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 | |
178 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_14 | |
179 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_17 | |
180 | ) | |
181 | ||
e03d7c66 MJ |
182 | dnl Test body for checking C++20 support |
183 | ||
184 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_20], | |
185 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_11 | |
186 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_14 | |
187 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_17 | |
188 | _AX_CXX_COMPILE_STDCXX_testbody_new_in_20 | |
189 | ) | |
190 | ||
191 | ||
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192 | dnl Tests for new features in C++11 |
193 | ||
194 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[ | |
195 | ||
196 | // If the compiler admits that it is not ready for C++11, why torture it? | |
197 | // Hopefully, this will speed up the test. | |
198 | ||
199 | #ifndef __cplusplus | |
200 | ||
201 | #error "This is not a C++ compiler" | |
202 | ||
e03d7c66 MJ |
203 | // MSVC always sets __cplusplus to 199711L in older versions; newer versions |
204 | // only set it correctly if /Zc:__cplusplus is specified as well as a | |
205 | // /std:c++NN switch: | |
206 | // https://devblogs.microsoft.com/cppblog/msvc-now-correctly-reports-__cplusplus/ | |
207 | #elif __cplusplus < 201103L && !defined _MSC_VER | |
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208 | |
209 | #error "This is not a C++11 compiler" | |
210 | ||
211 | #else | |
212 | ||
213 | namespace cxx11 | |
214 | { | |
215 | ||
216 | namespace test_static_assert | |
217 | { | |
218 | ||
219 | template <typename T> | |
220 | struct check | |
221 | { | |
222 | static_assert(sizeof(int) <= sizeof(T), "not big enough"); | |
223 | }; | |
224 | ||
225 | } | |
226 | ||
227 | namespace test_final_override | |
228 | { | |
229 | ||
230 | struct Base | |
231 | { | |
232 | virtual ~Base() {} | |
233 | virtual void f() {} | |
234 | }; | |
235 | ||
236 | struct Derived : public Base | |
237 | { | |
238 | virtual ~Derived() override {} | |
239 | virtual void f() override {} | |
240 | }; | |
241 | ||
242 | } | |
243 | ||
244 | namespace test_double_right_angle_brackets | |
245 | { | |
246 | ||
247 | template < typename T > | |
248 | struct check {}; | |
249 | ||
250 | typedef check<void> single_type; | |
251 | typedef check<check<void>> double_type; | |
252 | typedef check<check<check<void>>> triple_type; | |
253 | typedef check<check<check<check<void>>>> quadruple_type; | |
254 | ||
255 | } | |
256 | ||
257 | namespace test_decltype | |
258 | { | |
259 | ||
260 | int | |
261 | f() | |
262 | { | |
263 | int a = 1; | |
264 | decltype(a) b = 2; | |
265 | return a + b; | |
266 | } | |
267 | ||
268 | } | |
269 | ||
270 | namespace test_type_deduction | |
271 | { | |
272 | ||
273 | template < typename T1, typename T2 > | |
274 | struct is_same | |
275 | { | |
276 | static const bool value = false; | |
277 | }; | |
278 | ||
279 | template < typename T > | |
280 | struct is_same<T, T> | |
281 | { | |
282 | static const bool value = true; | |
283 | }; | |
284 | ||
285 | template < typename T1, typename T2 > | |
286 | auto | |
287 | add(T1 a1, T2 a2) -> decltype(a1 + a2) | |
288 | { | |
289 | return a1 + a2; | |
290 | } | |
291 | ||
292 | int | |
293 | test(const int c, volatile int v) | |
294 | { | |
295 | static_assert(is_same<int, decltype(0)>::value == true, ""); | |
296 | static_assert(is_same<int, decltype(c)>::value == false, ""); | |
297 | static_assert(is_same<int, decltype(v)>::value == false, ""); | |
298 | auto ac = c; | |
299 | auto av = v; | |
300 | auto sumi = ac + av + 'x'; | |
301 | auto sumf = ac + av + 1.0; | |
302 | static_assert(is_same<int, decltype(ac)>::value == true, ""); | |
303 | static_assert(is_same<int, decltype(av)>::value == true, ""); | |
304 | static_assert(is_same<int, decltype(sumi)>::value == true, ""); | |
305 | static_assert(is_same<int, decltype(sumf)>::value == false, ""); | |
306 | static_assert(is_same<int, decltype(add(c, v))>::value == true, ""); | |
307 | return (sumf > 0.0) ? sumi : add(c, v); | |
308 | } | |
309 | ||
310 | } | |
311 | ||
312 | namespace test_noexcept | |
313 | { | |
314 | ||
315 | int f() { return 0; } | |
316 | int g() noexcept { return 0; } | |
317 | ||
318 | static_assert(noexcept(f()) == false, ""); | |
319 | static_assert(noexcept(g()) == true, ""); | |
320 | ||
321 | } | |
322 | ||
323 | namespace test_constexpr | |
324 | { | |
325 | ||
326 | template < typename CharT > | |
327 | unsigned long constexpr | |
328 | strlen_c_r(const CharT *const s, const unsigned long acc) noexcept | |
329 | { | |
330 | return *s ? strlen_c_r(s + 1, acc + 1) : acc; | |
331 | } | |
332 | ||
333 | template < typename CharT > | |
334 | unsigned long constexpr | |
335 | strlen_c(const CharT *const s) noexcept | |
336 | { | |
337 | return strlen_c_r(s, 0UL); | |
338 | } | |
339 | ||
340 | static_assert(strlen_c("") == 0UL, ""); | |
341 | static_assert(strlen_c("1") == 1UL, ""); | |
342 | static_assert(strlen_c("example") == 7UL, ""); | |
343 | static_assert(strlen_c("another\0example") == 7UL, ""); | |
344 | ||
345 | } | |
346 | ||
347 | namespace test_rvalue_references | |
348 | { | |
349 | ||
350 | template < int N > | |
351 | struct answer | |
352 | { | |
353 | static constexpr int value = N; | |
354 | }; | |
355 | ||
356 | answer<1> f(int&) { return answer<1>(); } | |
357 | answer<2> f(const int&) { return answer<2>(); } | |
358 | answer<3> f(int&&) { return answer<3>(); } | |
359 | ||
360 | void | |
361 | test() | |
362 | { | |
363 | int i = 0; | |
364 | const int c = 0; | |
365 | static_assert(decltype(f(i))::value == 1, ""); | |
366 | static_assert(decltype(f(c))::value == 2, ""); | |
367 | static_assert(decltype(f(0))::value == 3, ""); | |
368 | } | |
369 | ||
370 | } | |
371 | ||
372 | namespace test_uniform_initialization | |
373 | { | |
374 | ||
375 | struct test | |
376 | { | |
377 | static const int zero {}; | |
378 | static const int one {1}; | |
379 | }; | |
380 | ||
381 | static_assert(test::zero == 0, ""); | |
382 | static_assert(test::one == 1, ""); | |
383 | ||
384 | } | |
385 | ||
386 | namespace test_lambdas | |
387 | { | |
388 | ||
389 | void | |
390 | test1() | |
391 | { | |
392 | auto lambda1 = [](){}; | |
393 | auto lambda2 = lambda1; | |
394 | lambda1(); | |
395 | lambda2(); | |
396 | } | |
397 | ||
398 | int | |
399 | test2() | |
400 | { | |
401 | auto a = [](int i, int j){ return i + j; }(1, 2); | |
402 | auto b = []() -> int { return '0'; }(); | |
403 | auto c = [=](){ return a + b; }(); | |
404 | auto d = [&](){ return c; }(); | |
405 | auto e = [a, &b](int x) mutable { | |
406 | const auto identity = [](int y){ return y; }; | |
407 | for (auto i = 0; i < a; ++i) | |
408 | a += b--; | |
409 | return x + identity(a + b); | |
410 | }(0); | |
411 | return a + b + c + d + e; | |
412 | } | |
413 | ||
414 | int | |
415 | test3() | |
416 | { | |
417 | const auto nullary = [](){ return 0; }; | |
418 | const auto unary = [](int x){ return x; }; | |
419 | using nullary_t = decltype(nullary); | |
420 | using unary_t = decltype(unary); | |
421 | const auto higher1st = [](nullary_t f){ return f(); }; | |
422 | const auto higher2nd = [unary](nullary_t f1){ | |
423 | return [unary, f1](unary_t f2){ return f2(unary(f1())); }; | |
424 | }; | |
425 | return higher1st(nullary) + higher2nd(nullary)(unary); | |
426 | } | |
427 | ||
428 | } | |
429 | ||
430 | namespace test_variadic_templates | |
431 | { | |
432 | ||
433 | template <int...> | |
434 | struct sum; | |
435 | ||
436 | template <int N0, int... N1toN> | |
437 | struct sum<N0, N1toN...> | |
438 | { | |
439 | static constexpr auto value = N0 + sum<N1toN...>::value; | |
440 | }; | |
441 | ||
442 | template <> | |
443 | struct sum<> | |
444 | { | |
445 | static constexpr auto value = 0; | |
446 | }; | |
447 | ||
448 | static_assert(sum<>::value == 0, ""); | |
449 | static_assert(sum<1>::value == 1, ""); | |
450 | static_assert(sum<23>::value == 23, ""); | |
451 | static_assert(sum<1, 2>::value == 3, ""); | |
452 | static_assert(sum<5, 5, 11>::value == 21, ""); | |
453 | static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, ""); | |
454 | ||
455 | } | |
456 | ||
457 | // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae | |
458 | // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function | |
459 | // because of this. | |
460 | namespace test_template_alias_sfinae | |
461 | { | |
462 | ||
463 | struct foo {}; | |
464 | ||
465 | template<typename T> | |
466 | using member = typename T::member_type; | |
467 | ||
468 | template<typename T> | |
469 | void func(...) {} | |
470 | ||
471 | template<typename T> | |
472 | void func(member<T>*) {} | |
473 | ||
474 | void test(); | |
475 | ||
476 | void test() { func<foo>(0); } | |
477 | ||
478 | } | |
479 | ||
480 | } // namespace cxx11 | |
481 | ||
482 | #endif // __cplusplus >= 201103L | |
483 | ||
484 | ]]) | |
485 | ||
486 | ||
487 | dnl Tests for new features in C++14 | |
488 | ||
489 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[ | |
490 | ||
491 | // If the compiler admits that it is not ready for C++14, why torture it? | |
492 | // Hopefully, this will speed up the test. | |
493 | ||
494 | #ifndef __cplusplus | |
495 | ||
496 | #error "This is not a C++ compiler" | |
497 | ||
e03d7c66 | 498 | #elif __cplusplus < 201402L && !defined _MSC_VER |
15b385c8 MD |
499 | |
500 | #error "This is not a C++14 compiler" | |
501 | ||
502 | #else | |
503 | ||
504 | namespace cxx14 | |
505 | { | |
506 | ||
507 | namespace test_polymorphic_lambdas | |
508 | { | |
509 | ||
510 | int | |
511 | test() | |
512 | { | |
513 | const auto lambda = [](auto&&... args){ | |
514 | const auto istiny = [](auto x){ | |
515 | return (sizeof(x) == 1UL) ? 1 : 0; | |
516 | }; | |
517 | const int aretiny[] = { istiny(args)... }; | |
518 | return aretiny[0]; | |
519 | }; | |
520 | return lambda(1, 1L, 1.0f, '1'); | |
521 | } | |
522 | ||
523 | } | |
524 | ||
525 | namespace test_binary_literals | |
526 | { | |
527 | ||
528 | constexpr auto ivii = 0b0000000000101010; | |
529 | static_assert(ivii == 42, "wrong value"); | |
530 | ||
531 | } | |
532 | ||
533 | namespace test_generalized_constexpr | |
534 | { | |
535 | ||
536 | template < typename CharT > | |
537 | constexpr unsigned long | |
538 | strlen_c(const CharT *const s) noexcept | |
539 | { | |
540 | auto length = 0UL; | |
541 | for (auto p = s; *p; ++p) | |
542 | ++length; | |
543 | return length; | |
544 | } | |
545 | ||
546 | static_assert(strlen_c("") == 0UL, ""); | |
547 | static_assert(strlen_c("x") == 1UL, ""); | |
548 | static_assert(strlen_c("test") == 4UL, ""); | |
549 | static_assert(strlen_c("another\0test") == 7UL, ""); | |
550 | ||
551 | } | |
552 | ||
553 | namespace test_lambda_init_capture | |
554 | { | |
555 | ||
556 | int | |
557 | test() | |
558 | { | |
559 | auto x = 0; | |
560 | const auto lambda1 = [a = x](int b){ return a + b; }; | |
561 | const auto lambda2 = [a = lambda1(x)](){ return a; }; | |
562 | return lambda2(); | |
563 | } | |
564 | ||
565 | } | |
566 | ||
567 | namespace test_digit_separators | |
568 | { | |
569 | ||
570 | constexpr auto ten_million = 100'000'000; | |
571 | static_assert(ten_million == 100000000, ""); | |
572 | ||
573 | } | |
574 | ||
575 | namespace test_return_type_deduction | |
576 | { | |
577 | ||
578 | auto f(int& x) { return x; } | |
579 | decltype(auto) g(int& x) { return x; } | |
580 | ||
581 | template < typename T1, typename T2 > | |
582 | struct is_same | |
583 | { | |
584 | static constexpr auto value = false; | |
585 | }; | |
586 | ||
587 | template < typename T > | |
588 | struct is_same<T, T> | |
589 | { | |
590 | static constexpr auto value = true; | |
591 | }; | |
592 | ||
593 | int | |
594 | test() | |
595 | { | |
596 | auto x = 0; | |
597 | static_assert(is_same<int, decltype(f(x))>::value, ""); | |
598 | static_assert(is_same<int&, decltype(g(x))>::value, ""); | |
599 | return x; | |
600 | } | |
601 | ||
602 | } | |
603 | ||
604 | } // namespace cxx14 | |
605 | ||
606 | #endif // __cplusplus >= 201402L | |
607 | ||
608 | ]]) | |
609 | ||
610 | ||
611 | dnl Tests for new features in C++17 | |
612 | ||
613 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_17], [[ | |
614 | ||
615 | // If the compiler admits that it is not ready for C++17, why torture it? | |
616 | // Hopefully, this will speed up the test. | |
617 | ||
618 | #ifndef __cplusplus | |
619 | ||
620 | #error "This is not a C++ compiler" | |
621 | ||
e03d7c66 | 622 | #elif __cplusplus < 201703L && !defined _MSC_VER |
15b385c8 MD |
623 | |
624 | #error "This is not a C++17 compiler" | |
625 | ||
626 | #else | |
627 | ||
628 | #include <initializer_list> | |
629 | #include <utility> | |
630 | #include <type_traits> | |
631 | ||
632 | namespace cxx17 | |
633 | { | |
634 | ||
635 | namespace test_constexpr_lambdas | |
636 | { | |
637 | ||
638 | constexpr int foo = [](){return 42;}(); | |
639 | ||
640 | } | |
641 | ||
642 | namespace test::nested_namespace::definitions | |
643 | { | |
644 | ||
645 | } | |
646 | ||
647 | namespace test_fold_expression | |
648 | { | |
649 | ||
650 | template<typename... Args> | |
651 | int multiply(Args... args) | |
652 | { | |
653 | return (args * ... * 1); | |
654 | } | |
655 | ||
656 | template<typename... Args> | |
657 | bool all(Args... args) | |
658 | { | |
659 | return (args && ...); | |
660 | } | |
661 | ||
662 | } | |
663 | ||
664 | namespace test_extended_static_assert | |
665 | { | |
666 | ||
667 | static_assert (true); | |
668 | ||
669 | } | |
670 | ||
671 | namespace test_auto_brace_init_list | |
672 | { | |
673 | ||
674 | auto foo = {5}; | |
675 | auto bar {5}; | |
676 | ||
677 | static_assert(std::is_same<std::initializer_list<int>, decltype(foo)>::value); | |
678 | static_assert(std::is_same<int, decltype(bar)>::value); | |
679 | } | |
680 | ||
681 | namespace test_typename_in_template_template_parameter | |
682 | { | |
683 | ||
684 | template<template<typename> typename X> struct D; | |
685 | ||
686 | } | |
687 | ||
688 | namespace test_fallthrough_nodiscard_maybe_unused_attributes | |
689 | { | |
690 | ||
691 | int f1() | |
692 | { | |
693 | return 42; | |
694 | } | |
695 | ||
696 | [[nodiscard]] int f2() | |
697 | { | |
698 | [[maybe_unused]] auto unused = f1(); | |
699 | ||
700 | switch (f1()) | |
701 | { | |
702 | case 17: | |
703 | f1(); | |
704 | [[fallthrough]]; | |
705 | case 42: | |
706 | f1(); | |
707 | } | |
708 | return f1(); | |
709 | } | |
710 | ||
711 | } | |
712 | ||
713 | namespace test_extended_aggregate_initialization | |
714 | { | |
715 | ||
716 | struct base1 | |
717 | { | |
718 | int b1, b2 = 42; | |
719 | }; | |
720 | ||
721 | struct base2 | |
722 | { | |
723 | base2() { | |
724 | b3 = 42; | |
725 | } | |
726 | int b3; | |
727 | }; | |
728 | ||
729 | struct derived : base1, base2 | |
730 | { | |
731 | int d; | |
732 | }; | |
733 | ||
734 | derived d1 {{1, 2}, {}, 4}; // full initialization | |
735 | derived d2 {{}, {}, 4}; // value-initialized bases | |
736 | ||
737 | } | |
738 | ||
739 | namespace test_general_range_based_for_loop | |
740 | { | |
741 | ||
742 | struct iter | |
743 | { | |
744 | int i; | |
745 | ||
746 | int& operator* () | |
747 | { | |
748 | return i; | |
749 | } | |
750 | ||
751 | const int& operator* () const | |
752 | { | |
753 | return i; | |
754 | } | |
755 | ||
756 | iter& operator++() | |
757 | { | |
758 | ++i; | |
759 | return *this; | |
760 | } | |
761 | }; | |
762 | ||
763 | struct sentinel | |
764 | { | |
765 | int i; | |
766 | }; | |
767 | ||
768 | bool operator== (const iter& i, const sentinel& s) | |
769 | { | |
770 | return i.i == s.i; | |
771 | } | |
772 | ||
773 | bool operator!= (const iter& i, const sentinel& s) | |
774 | { | |
775 | return !(i == s); | |
776 | } | |
777 | ||
778 | struct range | |
779 | { | |
780 | iter begin() const | |
781 | { | |
782 | return {0}; | |
783 | } | |
784 | ||
785 | sentinel end() const | |
786 | { | |
787 | return {5}; | |
788 | } | |
789 | }; | |
790 | ||
791 | void f() | |
792 | { | |
793 | range r {}; | |
794 | ||
795 | for (auto i : r) | |
796 | { | |
797 | [[maybe_unused]] auto v = i; | |
798 | } | |
799 | } | |
800 | ||
801 | } | |
802 | ||
803 | namespace test_lambda_capture_asterisk_this_by_value | |
804 | { | |
805 | ||
806 | struct t | |
807 | { | |
808 | int i; | |
809 | int foo() | |
810 | { | |
811 | return [*this]() | |
812 | { | |
813 | return i; | |
814 | }(); | |
815 | } | |
816 | }; | |
817 | ||
818 | } | |
819 | ||
820 | namespace test_enum_class_construction | |
821 | { | |
822 | ||
823 | enum class byte : unsigned char | |
824 | {}; | |
825 | ||
826 | byte foo {42}; | |
827 | ||
828 | } | |
829 | ||
830 | namespace test_constexpr_if | |
831 | { | |
832 | ||
833 | template <bool cond> | |
834 | int f () | |
835 | { | |
836 | if constexpr(cond) | |
837 | { | |
838 | return 13; | |
839 | } | |
840 | else | |
841 | { | |
842 | return 42; | |
843 | } | |
844 | } | |
845 | ||
846 | } | |
847 | ||
848 | namespace test_selection_statement_with_initializer | |
849 | { | |
850 | ||
851 | int f() | |
852 | { | |
853 | return 13; | |
854 | } | |
855 | ||
856 | int f2() | |
857 | { | |
858 | if (auto i = f(); i > 0) | |
859 | { | |
860 | return 3; | |
861 | } | |
862 | ||
863 | switch (auto i = f(); i + 4) | |
864 | { | |
865 | case 17: | |
866 | return 2; | |
867 | ||
868 | default: | |
869 | return 1; | |
870 | } | |
871 | } | |
872 | ||
873 | } | |
874 | ||
875 | namespace test_template_argument_deduction_for_class_templates | |
876 | { | |
877 | ||
878 | template <typename T1, typename T2> | |
879 | struct pair | |
880 | { | |
881 | pair (T1 p1, T2 p2) | |
882 | : m1 {p1}, | |
883 | m2 {p2} | |
884 | {} | |
885 | ||
886 | T1 m1; | |
887 | T2 m2; | |
888 | }; | |
889 | ||
890 | void f() | |
891 | { | |
892 | [[maybe_unused]] auto p = pair{13, 42u}; | |
893 | } | |
894 | ||
895 | } | |
896 | ||
897 | namespace test_non_type_auto_template_parameters | |
898 | { | |
899 | ||
900 | template <auto n> | |
901 | struct B | |
902 | {}; | |
903 | ||
904 | B<5> b1; | |
905 | B<'a'> b2; | |
906 | ||
907 | } | |
908 | ||
909 | namespace test_structured_bindings | |
910 | { | |
911 | ||
912 | int arr[2] = { 1, 2 }; | |
913 | std::pair<int, int> pr = { 1, 2 }; | |
914 | ||
915 | auto f1() -> int(&)[2] | |
916 | { | |
917 | return arr; | |
918 | } | |
919 | ||
920 | auto f2() -> std::pair<int, int>& | |
921 | { | |
922 | return pr; | |
923 | } | |
924 | ||
925 | struct S | |
926 | { | |
927 | int x1 : 2; | |
928 | volatile double y1; | |
929 | }; | |
930 | ||
931 | S f3() | |
932 | { | |
933 | return {}; | |
934 | } | |
935 | ||
936 | auto [ x1, y1 ] = f1(); | |
937 | auto& [ xr1, yr1 ] = f1(); | |
938 | auto [ x2, y2 ] = f2(); | |
939 | auto& [ xr2, yr2 ] = f2(); | |
940 | const auto [ x3, y3 ] = f3(); | |
941 | ||
942 | } | |
943 | ||
944 | namespace test_exception_spec_type_system | |
945 | { | |
946 | ||
947 | struct Good {}; | |
948 | struct Bad {}; | |
949 | ||
950 | void g1() noexcept; | |
951 | void g2(); | |
952 | ||
953 | template<typename T> | |
954 | Bad | |
955 | f(T*, T*); | |
956 | ||
957 | template<typename T1, typename T2> | |
958 | Good | |
959 | f(T1*, T2*); | |
960 | ||
961 | static_assert (std::is_same_v<Good, decltype(f(g1, g2))>); | |
962 | ||
963 | } | |
964 | ||
965 | namespace test_inline_variables | |
966 | { | |
967 | ||
968 | template<class T> void f(T) | |
969 | {} | |
970 | ||
971 | template<class T> inline T g(T) | |
972 | { | |
973 | return T{}; | |
974 | } | |
975 | ||
976 | template<> inline void f<>(int) | |
977 | {} | |
978 | ||
979 | template<> int g<>(int) | |
980 | { | |
981 | return 5; | |
982 | } | |
983 | ||
984 | } | |
985 | ||
986 | } // namespace cxx17 | |
987 | ||
e03d7c66 MJ |
988 | #endif // __cplusplus < 201703L && !defined _MSC_VER |
989 | ||
990 | ]]) | |
991 | ||
992 | ||
993 | dnl Tests for new features in C++20 | |
994 | ||
995 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_20], [[ | |
996 | ||
997 | #ifndef __cplusplus | |
998 | ||
999 | #error "This is not a C++ compiler" | |
1000 | ||
1001 | #elif __cplusplus < 202002L && !defined _MSC_VER | |
1002 | ||
1003 | #error "This is not a C++20 compiler" | |
1004 | ||
1005 | #else | |
1006 | ||
1007 | #include <version> | |
1008 | ||
1009 | namespace cxx20 | |
1010 | { | |
1011 | ||
1012 | // As C++20 supports feature test macros in the standard, there is no | |
1013 | // immediate need to actually test for feature availability on the | |
1014 | // Autoconf side. | |
1015 | ||
1016 | } // namespace cxx20 | |
1017 | ||
1018 | #endif // __cplusplus < 202002L && !defined _MSC_VER | |
15b385c8 MD |
1019 | |
1020 | ]]) |