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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 | # | |
37 | # Copying and distribution of this file, with or without modification, are | |
38 | # permitted in any medium without royalty provided the copyright notice | |
39 | # and this notice are preserved. This file is offered as-is, without any | |
40 | # warranty. | |
41 | ||
42 | #serial 4 | |
43 | ||
44 | dnl This macro is based on the code from the AX_CXX_COMPILE_STDCXX_11 macro | |
45 | dnl (serial version number 13). | |
46 | ||
47 | AC_DEFUN([AX_CXX_COMPILE_STDCXX], [dnl | |
48 | m4_if([$1], [11], [], | |
49 | [$1], [14], [], | |
50 | [$1], [17], [m4_fatal([support for C++17 not yet implemented in AX_CXX_COMPILE_STDCXX])], | |
51 | [m4_fatal([invalid first argument `$1' to AX_CXX_COMPILE_STDCXX])])dnl | |
52 | m4_if([$2], [], [], | |
53 | [$2], [ext], [], | |
54 | [$2], [noext], [], | |
55 | [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX])])dnl | |
56 | m4_if([$3], [], [ax_cxx_compile_cxx$1_required=true], | |
57 | [$3], [mandatory], [ax_cxx_compile_cxx$1_required=true], | |
58 | [$3], [optional], [ax_cxx_compile_cxx$1_required=false], | |
59 | [m4_fatal([invalid third argument `$3' to AX_CXX_COMPILE_STDCXX])]) | |
60 | AC_LANG_PUSH([C++])dnl | |
61 | ac_success=no | |
62 | AC_CACHE_CHECK(whether $CXX supports C++$1 features by default, | |
63 | ax_cv_cxx_compile_cxx$1, | |
64 | [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], | |
65 | [ax_cv_cxx_compile_cxx$1=yes], | |
66 | [ax_cv_cxx_compile_cxx$1=no])]) | |
67 | if test x$ax_cv_cxx_compile_cxx$1 = xyes; then | |
68 | ac_success=yes | |
69 | fi | |
70 | ||
71 | m4_if([$2], [noext], [], [dnl | |
72 | if test x$ac_success = xno; then | |
73 | for switch in -std=gnu++$1 -std=gnu++0x; do | |
74 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) | |
75 | AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, | |
76 | $cachevar, | |
77 | [ac_save_CXX="$CXX" | |
78 | CXX="$CXX $switch" | |
79 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], | |
80 | [eval $cachevar=yes], | |
81 | [eval $cachevar=no]) | |
82 | CXX="$ac_save_CXX"]) | |
83 | if eval test x\$$cachevar = xyes; then | |
84 | CXX="$CXX $switch" | |
85 | if test -n "$CXXCPP" ; then | |
86 | CXXCPP="$CXXCPP $switch" | |
87 | fi | |
88 | ac_success=yes | |
89 | break | |
90 | fi | |
91 | done | |
92 | fi]) | |
93 | ||
94 | m4_if([$2], [ext], [], [dnl | |
95 | if test x$ac_success = xno; then | |
96 | dnl HP's aCC needs +std=c++11 according to: | |
97 | dnl http://h21007.www2.hp.com/portal/download/files/unprot/aCxx/PDF_Release_Notes/769149-001.pdf | |
98 | dnl Cray's crayCC needs "-h std=c++11" | |
99 | for switch in -std=c++$1 -std=c++0x +std=c++$1 "-h std=c++$1"; do | |
100 | cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx$1_$switch]) | |
101 | AC_CACHE_CHECK(whether $CXX supports C++$1 features with $switch, | |
102 | $cachevar, | |
103 | [ac_save_CXX="$CXX" | |
104 | CXX="$CXX $switch" | |
105 | AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_testbody_$1])], | |
106 | [eval $cachevar=yes], | |
107 | [eval $cachevar=no]) | |
108 | CXX="$ac_save_CXX"]) | |
109 | if eval test x\$$cachevar = xyes; then | |
110 | CXX="$CXX $switch" | |
111 | if test -n "$CXXCPP" ; then | |
112 | CXXCPP="$CXXCPP $switch" | |
113 | fi | |
114 | ac_success=yes | |
115 | break | |
116 | fi | |
117 | done | |
118 | fi]) | |
119 | AC_LANG_POP([C++]) | |
120 | if test x$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 | ||
152 | dnl Tests for new features in C++11 | |
153 | ||
154 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_11], [[ | |
155 | ||
156 | // If the compiler admits that it is not ready for C++11, why torture it? | |
157 | // Hopefully, this will speed up the test. | |
158 | ||
159 | #ifndef __cplusplus | |
160 | ||
161 | #error "This is not a C++ compiler" | |
162 | ||
163 | #elif __cplusplus < 201103L | |
164 | ||
165 | #error "This is not a C++11 compiler" | |
166 | ||
167 | #else | |
168 | ||
169 | namespace cxx11 | |
170 | { | |
171 | ||
172 | namespace test_static_assert | |
173 | { | |
174 | ||
175 | template <typename T> | |
176 | struct check | |
177 | { | |
178 | static_assert(sizeof(int) <= sizeof(T), "not big enough"); | |
179 | }; | |
180 | ||
181 | } | |
182 | ||
183 | namespace test_final_override | |
184 | { | |
185 | ||
186 | struct Base | |
187 | { | |
188 | virtual void f() {} | |
189 | }; | |
190 | ||
191 | struct Derived : public Base | |
192 | { | |
193 | virtual void f() override {} | |
194 | }; | |
195 | ||
196 | } | |
197 | ||
198 | namespace test_double_right_angle_brackets | |
199 | { | |
200 | ||
201 | template < typename T > | |
202 | struct check {}; | |
203 | ||
204 | typedef check<void> single_type; | |
205 | typedef check<check<void>> double_type; | |
206 | typedef check<check<check<void>>> triple_type; | |
207 | typedef check<check<check<check<void>>>> quadruple_type; | |
208 | ||
209 | } | |
210 | ||
211 | namespace test_decltype | |
212 | { | |
213 | ||
214 | int | |
215 | f() | |
216 | { | |
217 | int a = 1; | |
218 | decltype(a) b = 2; | |
219 | return a + b; | |
220 | } | |
221 | ||
222 | } | |
223 | ||
224 | namespace test_type_deduction | |
225 | { | |
226 | ||
227 | template < typename T1, typename T2 > | |
228 | struct is_same | |
229 | { | |
230 | static const bool value = false; | |
231 | }; | |
232 | ||
233 | template < typename T > | |
234 | struct is_same<T, T> | |
235 | { | |
236 | static const bool value = true; | |
237 | }; | |
238 | ||
239 | template < typename T1, typename T2 > | |
240 | auto | |
241 | add(T1 a1, T2 a2) -> decltype(a1 + a2) | |
242 | { | |
243 | return a1 + a2; | |
244 | } | |
245 | ||
246 | int | |
247 | test(const int c, volatile int v) | |
248 | { | |
249 | static_assert(is_same<int, decltype(0)>::value == true, ""); | |
250 | static_assert(is_same<int, decltype(c)>::value == false, ""); | |
251 | static_assert(is_same<int, decltype(v)>::value == false, ""); | |
252 | auto ac = c; | |
253 | auto av = v; | |
254 | auto sumi = ac + av + 'x'; | |
255 | auto sumf = ac + av + 1.0; | |
256 | static_assert(is_same<int, decltype(ac)>::value == true, ""); | |
257 | static_assert(is_same<int, decltype(av)>::value == true, ""); | |
258 | static_assert(is_same<int, decltype(sumi)>::value == true, ""); | |
259 | static_assert(is_same<int, decltype(sumf)>::value == false, ""); | |
260 | static_assert(is_same<int, decltype(add(c, v))>::value == true, ""); | |
261 | return (sumf > 0.0) ? sumi : add(c, v); | |
262 | } | |
263 | ||
264 | } | |
265 | ||
266 | namespace test_noexcept | |
267 | { | |
268 | ||
269 | int f() { return 0; } | |
270 | int g() noexcept { return 0; } | |
271 | ||
272 | static_assert(noexcept(f()) == false, ""); | |
273 | static_assert(noexcept(g()) == true, ""); | |
274 | ||
275 | } | |
276 | ||
277 | namespace test_constexpr | |
278 | { | |
279 | ||
280 | template < typename CharT > | |
281 | unsigned long constexpr | |
282 | strlen_c_r(const CharT *const s, const unsigned long acc) noexcept | |
283 | { | |
284 | return *s ? strlen_c_r(s + 1, acc + 1) : acc; | |
285 | } | |
286 | ||
287 | template < typename CharT > | |
288 | unsigned long constexpr | |
289 | strlen_c(const CharT *const s) noexcept | |
290 | { | |
291 | return strlen_c_r(s, 0UL); | |
292 | } | |
293 | ||
294 | static_assert(strlen_c("") == 0UL, ""); | |
295 | static_assert(strlen_c("1") == 1UL, ""); | |
296 | static_assert(strlen_c("example") == 7UL, ""); | |
297 | static_assert(strlen_c("another\0example") == 7UL, ""); | |
298 | ||
299 | } | |
300 | ||
301 | namespace test_rvalue_references | |
302 | { | |
303 | ||
304 | template < int N > | |
305 | struct answer | |
306 | { | |
307 | static constexpr int value = N; | |
308 | }; | |
309 | ||
310 | answer<1> f(int&) { return answer<1>(); } | |
311 | answer<2> f(const int&) { return answer<2>(); } | |
312 | answer<3> f(int&&) { return answer<3>(); } | |
313 | ||
314 | void | |
315 | test() | |
316 | { | |
317 | int i = 0; | |
318 | const int c = 0; | |
319 | static_assert(decltype(f(i))::value == 1, ""); | |
320 | static_assert(decltype(f(c))::value == 2, ""); | |
321 | static_assert(decltype(f(0))::value == 3, ""); | |
322 | } | |
323 | ||
324 | } | |
325 | ||
326 | namespace test_uniform_initialization | |
327 | { | |
328 | ||
329 | struct test | |
330 | { | |
331 | static const int zero {}; | |
332 | static const int one {1}; | |
333 | }; | |
334 | ||
335 | static_assert(test::zero == 0, ""); | |
336 | static_assert(test::one == 1, ""); | |
337 | ||
338 | } | |
339 | ||
340 | namespace test_lambdas | |
341 | { | |
342 | ||
343 | void | |
344 | test1() | |
345 | { | |
346 | auto lambda1 = [](){}; | |
347 | auto lambda2 = lambda1; | |
348 | lambda1(); | |
349 | lambda2(); | |
350 | } | |
351 | ||
352 | int | |
353 | test2() | |
354 | { | |
355 | auto a = [](int i, int j){ return i + j; }(1, 2); | |
356 | auto b = []() -> int { return '0'; }(); | |
357 | auto c = [=](){ return a + b; }(); | |
358 | auto d = [&](){ return c; }(); | |
359 | auto e = [a, &b](int x) mutable { | |
360 | const auto identity = [](int y){ return y; }; | |
361 | for (auto i = 0; i < a; ++i) | |
362 | a += b--; | |
363 | return x + identity(a + b); | |
364 | }(0); | |
365 | return a + b + c + d + e; | |
366 | } | |
367 | ||
368 | int | |
369 | test3() | |
370 | { | |
371 | const auto nullary = [](){ return 0; }; | |
372 | const auto unary = [](int x){ return x; }; | |
373 | using nullary_t = decltype(nullary); | |
374 | using unary_t = decltype(unary); | |
375 | const auto higher1st = [](nullary_t f){ return f(); }; | |
376 | const auto higher2nd = [unary](nullary_t f1){ | |
377 | return [unary, f1](unary_t f2){ return f2(unary(f1())); }; | |
378 | }; | |
379 | return higher1st(nullary) + higher2nd(nullary)(unary); | |
380 | } | |
381 | ||
382 | } | |
383 | ||
384 | namespace test_variadic_templates | |
385 | { | |
386 | ||
387 | template <int...> | |
388 | struct sum; | |
389 | ||
390 | template <int N0, int... N1toN> | |
391 | struct sum<N0, N1toN...> | |
392 | { | |
393 | static constexpr auto value = N0 + sum<N1toN...>::value; | |
394 | }; | |
395 | ||
396 | template <> | |
397 | struct sum<> | |
398 | { | |
399 | static constexpr auto value = 0; | |
400 | }; | |
401 | ||
402 | static_assert(sum<>::value == 0, ""); | |
403 | static_assert(sum<1>::value == 1, ""); | |
404 | static_assert(sum<23>::value == 23, ""); | |
405 | static_assert(sum<1, 2>::value == 3, ""); | |
406 | static_assert(sum<5, 5, 11>::value == 21, ""); | |
407 | static_assert(sum<2, 3, 5, 7, 11, 13>::value == 41, ""); | |
408 | ||
409 | } | |
410 | ||
411 | // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae | |
412 | // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function | |
413 | // because of this. | |
414 | namespace test_template_alias_sfinae | |
415 | { | |
416 | ||
417 | struct foo {}; | |
418 | ||
419 | template<typename T> | |
420 | using member = typename T::member_type; | |
421 | ||
422 | template<typename T> | |
423 | void func(...) {} | |
424 | ||
425 | template<typename T> | |
426 | void func(member<T>*) {} | |
427 | ||
428 | void test(); | |
429 | ||
430 | void test() { func<foo>(0); } | |
431 | ||
432 | } | |
433 | ||
434 | } // namespace cxx11 | |
435 | ||
436 | #endif // __cplusplus >= 201103L | |
437 | ||
438 | ]]) | |
439 | ||
440 | ||
441 | dnl Tests for new features in C++14 | |
442 | ||
443 | m4_define([_AX_CXX_COMPILE_STDCXX_testbody_new_in_14], [[ | |
444 | ||
445 | // If the compiler admits that it is not ready for C++14, why torture it? | |
446 | // Hopefully, this will speed up the test. | |
447 | ||
448 | #ifndef __cplusplus | |
449 | ||
450 | #error "This is not a C++ compiler" | |
451 | ||
452 | #elif __cplusplus < 201402L | |
453 | ||
454 | #error "This is not a C++14 compiler" | |
455 | ||
456 | #else | |
457 | ||
458 | namespace cxx14 | |
459 | { | |
460 | ||
461 | namespace test_polymorphic_lambdas | |
462 | { | |
463 | ||
464 | int | |
465 | test() | |
466 | { | |
467 | const auto lambda = [](auto&&... args){ | |
468 | const auto istiny = [](auto x){ | |
469 | return (sizeof(x) == 1UL) ? 1 : 0; | |
470 | }; | |
471 | const int aretiny[] = { istiny(args)... }; | |
472 | return aretiny[0]; | |
473 | }; | |
474 | return lambda(1, 1L, 1.0f, '1'); | |
475 | } | |
476 | ||
477 | } | |
478 | ||
479 | namespace test_binary_literals | |
480 | { | |
481 | ||
482 | constexpr auto ivii = 0b0000000000101010; | |
483 | static_assert(ivii == 42, "wrong value"); | |
484 | ||
485 | } | |
486 | ||
487 | namespace test_generalized_constexpr | |
488 | { | |
489 | ||
490 | template < typename CharT > | |
491 | constexpr unsigned long | |
492 | strlen_c(const CharT *const s) noexcept | |
493 | { | |
494 | auto length = 0UL; | |
495 | for (auto p = s; *p; ++p) | |
496 | ++length; | |
497 | return length; | |
498 | } | |
499 | ||
500 | static_assert(strlen_c("") == 0UL, ""); | |
501 | static_assert(strlen_c("x") == 1UL, ""); | |
502 | static_assert(strlen_c("test") == 4UL, ""); | |
503 | static_assert(strlen_c("another\0test") == 7UL, ""); | |
504 | ||
505 | } | |
506 | ||
507 | namespace test_lambda_init_capture | |
508 | { | |
509 | ||
510 | int | |
511 | test() | |
512 | { | |
513 | auto x = 0; | |
514 | const auto lambda1 = [a = x](int b){ return a + b; }; | |
515 | const auto lambda2 = [a = lambda1(x)](){ return a; }; | |
516 | return lambda2(); | |
517 | } | |
518 | ||
519 | } | |
520 | ||
521 | namespace test_digit_seperators | |
522 | { | |
523 | ||
524 | constexpr auto ten_million = 100'000'000; | |
525 | static_assert(ten_million == 100000000, ""); | |
526 | ||
527 | } | |
528 | ||
529 | namespace test_return_type_deduction | |
530 | { | |
531 | ||
532 | auto f(int& x) { return x; } | |
533 | decltype(auto) g(int& x) { return x; } | |
534 | ||
535 | template < typename T1, typename T2 > | |
536 | struct is_same | |
537 | { | |
538 | static constexpr auto value = false; | |
539 | }; | |
540 | ||
541 | template < typename T > | |
542 | struct is_same<T, T> | |
543 | { | |
544 | static constexpr auto value = true; | |
545 | }; | |
546 | ||
547 | int | |
548 | test() | |
549 | { | |
550 | auto x = 0; | |
551 | static_assert(is_same<int, decltype(f(x))>::value, ""); | |
552 | static_assert(is_same<int&, decltype(g(x))>::value, ""); | |
553 | return x; | |
554 | } | |
555 | ||
556 | } | |
557 | ||
558 | } // namespace cxx14 | |
559 | ||
560 | #endif // __cplusplus >= 201402L | |
561 | ||
562 | ]]) |