1 // 2 // Copyright 2017 The Abseil Authors. 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // https://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 // ----------------------------------------------------------------------------- 17 // File: config.h 18 // ----------------------------------------------------------------------------- 19 // 20 // This header file defines a set of macros for checking the presence of 21 // important compiler and platform features. Such macros can be used to 22 // produce portable code by parameterizing compilation based on the presence or 23 // lack of a given feature. 24 // 25 // We define a "feature" as some interface we wish to program to: for example, 26 // a library function or system call. A value of `1` indicates support for 27 // that feature; any other value indicates the feature support is undefined. 28 // 29 // Example: 30 // 31 // Suppose a programmer wants to write a program that uses the 'mmap()' system 32 // call. The Abseil macro for that feature (`ABSL_HAVE_MMAP`) allows you to 33 // selectively include the `mmap.h` header and bracket code using that feature 34 // in the macro: 35 // 36 // #include "absl/base/config.h" 37 // 38 // #ifdef ABSL_HAVE_MMAP 39 // #include "sys/mman.h" 40 // #endif //ABSL_HAVE_MMAP 41 // 42 // ... 43 // #ifdef ABSL_HAVE_MMAP 44 // void *ptr = mmap(...); 45 // ... 46 // #endif // ABSL_HAVE_MMAP 47 48 #ifndef ABSL_BASE_CONFIG_H_ 49 #define ABSL_BASE_CONFIG_H_ 50 51 // Included for the __GLIBC__ macro (or similar macros on other systems). 52 #include <limits.h> 53 54 #ifdef __cplusplus 55 // Included for __GLIBCXX__, _LIBCPP_VERSION 56 #include <cstddef> 57 #endif // __cplusplus 58 59 #if defined(__APPLE__) 60 // Included for TARGET_OS_IPHONE, __IPHONE_OS_VERSION_MIN_REQUIRED, 61 // __IPHONE_8_0. 62 #include <Availability.h> 63 #include <TargetConditionals.h> 64 #endif 65 66 #include "absl/base/options.h" 67 #include "absl/base/policy_checks.h" 68 69 // Helper macro to convert a CPP variable to a string literal. 70 #define ABSL_INTERNAL_DO_TOKEN_STR(x) #x 71 #define ABSL_INTERNAL_TOKEN_STR(x) ABSL_INTERNAL_DO_TOKEN_STR(x) 72 73 // ----------------------------------------------------------------------------- 74 // Abseil namespace annotations 75 // ----------------------------------------------------------------------------- 76 77 // ABSL_NAMESPACE_BEGIN/ABSL_NAMESPACE_END 78 // 79 // An annotation placed at the beginning/end of each `namespace absl` scope. 80 // This is used to inject an inline namespace. 81 // 82 // The proper way to write Abseil code in the `absl` namespace is: 83 // 84 // namespace absl { 85 // ABSL_NAMESPACE_BEGIN 86 // 87 // void Foo(); // absl::Foo(). 88 // 89 // ABSL_NAMESPACE_END 90 // } // namespace absl 91 // 92 // Users of Abseil should not use these macros, because users of Abseil should 93 // not write `namespace absl {` in their own code for any reason. (Abseil does 94 // not support forward declarations of its own types, nor does it support 95 // user-provided specialization of Abseil templates. Code that violates these 96 // rules may be broken without warning.) 97 #if !defined(ABSL_OPTION_USE_INLINE_NAMESPACE) || \ 98 !defined(ABSL_OPTION_INLINE_NAMESPACE_NAME) 99 #error options.h is misconfigured. 100 #endif 101 102 // Check that ABSL_OPTION_INLINE_NAMESPACE_NAME is neither "head" nor "" 103 #if defined(__cplusplus) && ABSL_OPTION_USE_INLINE_NAMESPACE == 1 104 105 #define ABSL_INTERNAL_INLINE_NAMESPACE_STR \ 106 ABSL_INTERNAL_TOKEN_STR(ABSL_OPTION_INLINE_NAMESPACE_NAME) 107 108 static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != '\0', 109 "options.h misconfigured: ABSL_OPTION_INLINE_NAMESPACE_NAME must " 110 "not be empty."); 111 static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' || 112 ABSL_INTERNAL_INLINE_NAMESPACE_STR[1] != 'e' || 113 ABSL_INTERNAL_INLINE_NAMESPACE_STR[2] != 'a' || 114 ABSL_INTERNAL_INLINE_NAMESPACE_STR[3] != 'd' || 115 ABSL_INTERNAL_INLINE_NAMESPACE_STR[4] != '\0', 116 "options.h misconfigured: ABSL_OPTION_INLINE_NAMESPACE_NAME must " 117 "be changed to a new, unique identifier name."); 118 119 #endif 120 121 #if ABSL_OPTION_USE_INLINE_NAMESPACE == 0 122 #define ABSL_NAMESPACE_BEGIN 123 #define ABSL_NAMESPACE_END 124 #define ABSL_INTERNAL_C_SYMBOL(x) x 125 #elif ABSL_OPTION_USE_INLINE_NAMESPACE == 1 126 #define ABSL_NAMESPACE_BEGIN \ 127 inline namespace ABSL_OPTION_INLINE_NAMESPACE_NAME { 128 #define ABSL_NAMESPACE_END } 129 #define ABSL_INTERNAL_C_SYMBOL_HELPER_2(x, v) x##_##v 130 #define ABSL_INTERNAL_C_SYMBOL_HELPER_1(x, v) \ 131 ABSL_INTERNAL_C_SYMBOL_HELPER_2(x, v) 132 #define ABSL_INTERNAL_C_SYMBOL(x) \ 133 ABSL_INTERNAL_C_SYMBOL_HELPER_1(x, ABSL_OPTION_INLINE_NAMESPACE_NAME) 134 #else 135 #error options.h is misconfigured. 136 #endif 137 138 // ----------------------------------------------------------------------------- 139 // Compiler Feature Checks 140 // ----------------------------------------------------------------------------- 141 142 // ABSL_HAVE_BUILTIN() 143 // 144 // Checks whether the compiler supports a Clang Feature Checking Macro, and if 145 // so, checks whether it supports the provided builtin function "x" where x 146 // is one of the functions noted in 147 // https://clang.llvm.org/docs/LanguageExtensions.html 148 // 149 // Note: Use this macro to avoid an extra level of #ifdef __has_builtin check. 150 // http://releases.llvm.org/3.3/tools/clang/docs/LanguageExtensions.html 151 #ifdef __has_builtin 152 #define ABSL_HAVE_BUILTIN(x) __has_builtin(x) 153 #else 154 #define ABSL_HAVE_BUILTIN(x) 0 155 #endif 156 157 #if defined(__is_identifier) 158 #define ABSL_INTERNAL_HAS_KEYWORD(x) !(__is_identifier(x)) 159 #else 160 #define ABSL_INTERNAL_HAS_KEYWORD(x) 0 161 #endif 162 163 #ifdef __has_feature 164 #define ABSL_HAVE_FEATURE(f) __has_feature(f) 165 #else 166 #define ABSL_HAVE_FEATURE(f) 0 167 #endif 168 169 // ABSL_HAVE_TLS is defined to 1 when __thread should be supported. 170 // We assume __thread is supported on Linux when compiled with Clang or compiled 171 // against libstdc++ with _GLIBCXX_HAVE_TLS defined. 172 #ifdef ABSL_HAVE_TLS 173 #error ABSL_HAVE_TLS cannot be directly set 174 #elif defined(__linux__) && (defined(__clang__) || defined(_GLIBCXX_HAVE_TLS)) 175 #define ABSL_HAVE_TLS 1 176 #endif 177 178 // ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE 179 // 180 // Checks whether `std::is_trivially_destructible<T>` is supported. 181 // 182 // Notes: All supported compilers using libc++ support this feature, as does 183 // gcc >= 4.8.1 using libstdc++, and Visual Studio. 184 #ifdef ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE 185 #error ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE cannot be directly set 186 #elif defined(_LIBCPP_VERSION) || \ 187 (!defined(__clang__) && defined(__GNUC__) && defined(__GLIBCXX__) && \ 188 (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) || \ 189 defined(_MSC_VER) 190 #define ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE 1 191 #endif 192 193 // ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE 194 // 195 // Checks whether `std::is_trivially_default_constructible<T>` and 196 // `std::is_trivially_copy_constructible<T>` are supported. 197 198 // ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE 199 // 200 // Checks whether `std::is_trivially_copy_assignable<T>` is supported. 201 202 // Notes: Clang with libc++ supports these features, as does gcc >= 5.1 with 203 // either libc++ or libstdc++, and Visual Studio (but not NVCC). 204 #if defined(ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE) 205 #error ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE cannot be directly set 206 #elif defined(ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE) 207 #error ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE cannot directly set 208 #elif (defined(__clang__) && defined(_LIBCPP_VERSION)) || \ 209 (!defined(__clang__) && defined(__GNUC__) && \ 210 (__GNUC__ > 7 || (__GNUC__ == 7 && __GNUC_MINOR__ >= 4)) && \ 211 (defined(_LIBCPP_VERSION) || defined(__GLIBCXX__))) || \ 212 (defined(_MSC_VER) && !defined(__NVCC__)) 213 #define ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE 1 214 #define ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE 1 215 #endif 216 217 // ABSL_HAVE_SOURCE_LOCATION_CURRENT 218 // 219 // Indicates whether `absl::SourceLocation::current()` will return useful 220 // information in some contexts. 221 #ifndef ABSL_HAVE_SOURCE_LOCATION_CURRENT 222 #if ABSL_INTERNAL_HAS_KEYWORD(__builtin_LINE) && \ 223 ABSL_INTERNAL_HAS_KEYWORD(__builtin_FILE) 224 #define ABSL_HAVE_SOURCE_LOCATION_CURRENT 1 225 #elif defined(__GNUC__) && __GNUC__ >= 5 226 #define ABSL_HAVE_SOURCE_LOCATION_CURRENT 1 227 #endif 228 #endif 229 230 // ABSL_HAVE_THREAD_LOCAL 231 // 232 // Checks whether C++11's `thread_local` storage duration specifier is 233 // supported. 234 #ifdef ABSL_HAVE_THREAD_LOCAL 235 #error ABSL_HAVE_THREAD_LOCAL cannot be directly set 236 #elif defined(__APPLE__) 237 // Notes: 238 // * Xcode's clang did not support `thread_local` until version 8, and 239 // even then not for all iOS < 9.0. 240 // * Xcode 9.3 started disallowing `thread_local` for 32-bit iOS simulator 241 // targeting iOS 9.x. 242 // * Xcode 10 moves the deployment target check for iOS < 9.0 to link time 243 // making ABSL_HAVE_FEATURE unreliable there. 244 // 245 #if ABSL_HAVE_FEATURE(cxx_thread_local) && \ 246 !(TARGET_OS_IPHONE && __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_9_0) 247 #define ABSL_HAVE_THREAD_LOCAL 1 248 #endif 249 #else // !defined(__APPLE__) 250 #define ABSL_HAVE_THREAD_LOCAL 1 251 #endif 252 253 // There are platforms for which TLS should not be used even though the compiler 254 // makes it seem like it's supported (Android NDK < r12b for example). 255 // This is primarily because of linker problems and toolchain misconfiguration: 256 // Abseil does not intend to support this indefinitely. Currently, the newest 257 // toolchain that we intend to support that requires this behavior is the 258 // r11 NDK - allowing for a 5 year support window on that means this option 259 // is likely to be removed around June of 2021. 260 // TLS isn't supported until NDK r12b per 261 // https://developer.android.com/ndk/downloads/revision_history.html 262 // Since NDK r16, `__NDK_MAJOR__` and `__NDK_MINOR__` are defined in 263 // <android/ndk-version.h>. For NDK < r16, users should define these macros, 264 // e.g. `-D__NDK_MAJOR__=11 -D__NKD_MINOR__=0` for NDK r11. 265 #if defined(__ANDROID__) && defined(__clang__) 266 #if __has_include(<android/ndk-version.h>) 267 #include <android/ndk-version.h> 268 #endif // __has_include(<android/ndk-version.h>) 269 #if defined(__ANDROID__) && defined(__clang__) && defined(__NDK_MAJOR__) && \ 270 defined(__NDK_MINOR__) && \ 271 ((__NDK_MAJOR__ < 12) || ((__NDK_MAJOR__ == 12) && (__NDK_MINOR__ < 1))) 272 #undef ABSL_HAVE_TLS 273 #undef ABSL_HAVE_THREAD_LOCAL 274 #endif 275 #endif // defined(__ANDROID__) && defined(__clang__) 276 277 // ABSL_HAVE_INTRINSIC_INT128 278 // 279 // Checks whether the __int128 compiler extension for a 128-bit integral type is 280 // supported. 281 // 282 // Note: __SIZEOF_INT128__ is defined by Clang and GCC when __int128 is 283 // supported, but we avoid using it in certain cases: 284 // * On Clang: 285 // * Building using Clang for Windows, where the Clang runtime library has 286 // 128-bit support only on LP64 architectures, but Windows is LLP64. 287 // * On Nvidia's nvcc: 288 // * nvcc also defines __GNUC__ and __SIZEOF_INT128__, but not all versions 289 // actually support __int128. 290 #ifdef ABSL_HAVE_INTRINSIC_INT128 291 #error ABSL_HAVE_INTRINSIC_INT128 cannot be directly set 292 #elif defined(__SIZEOF_INT128__) 293 #if (defined(__clang__) && !defined(_WIN32)) || \ 294 (defined(__CUDACC__) && __CUDACC_VER_MAJOR__ >= 9) || \ 295 (defined(__GNUC__) && !defined(__clang__) && !defined(__CUDACC__)) 296 #define ABSL_HAVE_INTRINSIC_INT128 1 297 #elif defined(__CUDACC__) 298 // __CUDACC_VER__ is a full version number before CUDA 9, and is defined to a 299 // string explaining that it has been removed starting with CUDA 9. We use 300 // nested #ifs because there is no short-circuiting in the preprocessor. 301 // NOTE: `__CUDACC__` could be undefined while `__CUDACC_VER__` is defined. 302 #if __CUDACC_VER__ >= 70000 303 #define ABSL_HAVE_INTRINSIC_INT128 1 304 #endif // __CUDACC_VER__ >= 70000 305 #endif // defined(__CUDACC__) 306 #endif // ABSL_HAVE_INTRINSIC_INT128 307 308 // ABSL_HAVE_EXCEPTIONS 309 // 310 // Checks whether the compiler both supports and enables exceptions. Many 311 // compilers support a "no exceptions" mode that disables exceptions. 312 // 313 // Generally, when ABSL_HAVE_EXCEPTIONS is not defined: 314 // 315 // * Code using `throw` and `try` may not compile. 316 // * The `noexcept` specifier will still compile and behave as normal. 317 // * The `noexcept` operator may still return `false`. 318 // 319 // For further details, consult the compiler's documentation. 320 #ifdef ABSL_HAVE_EXCEPTIONS 321 #error ABSL_HAVE_EXCEPTIONS cannot be directly set. 322 323 #elif defined(__clang__) 324 325 #if __clang_major__ > 3 || (__clang_major__ == 3 && __clang_minor__ >= 6) 326 // Clang >= 3.6 327 #if ABSL_HAVE_FEATURE(cxx_exceptions) 328 #define ABSL_HAVE_EXCEPTIONS 1 329 #endif // ABSL_HAVE_FEATURE(cxx_exceptions) 330 #else 331 // Clang < 3.6 332 // http://releases.llvm.org/3.6.0/tools/clang/docs/ReleaseNotes.html#the-exceptions-macro 333 #if defined(__EXCEPTIONS) && ABSL_HAVE_FEATURE(cxx_exceptions) 334 #define ABSL_HAVE_EXCEPTIONS 1 335 #endif // defined(__EXCEPTIONS) && ABSL_HAVE_FEATURE(cxx_exceptions) 336 #endif // __clang_major__ > 3 || (__clang_major__ == 3 && __clang_minor__ >= 6) 337 338 // Handle remaining special cases and default to exceptions being supported. 339 #elif !(defined(__GNUC__) && (__GNUC__ < 5) && !defined(__EXCEPTIONS)) && \ 340 !(defined(__GNUC__) && (__GNUC__ >= 5) && !defined(__cpp_exceptions)) && \ 341 !(defined(_MSC_VER) && !defined(_CPPUNWIND)) 342 #define ABSL_HAVE_EXCEPTIONS 1 343 #endif 344 345 // ----------------------------------------------------------------------------- 346 // Platform Feature Checks 347 // ----------------------------------------------------------------------------- 348 349 // Currently supported operating systems and associated preprocessor 350 // symbols: 351 // 352 // Linux and Linux-derived __linux__ 353 // Android __ANDROID__ (implies __linux__) 354 // Linux (non-Android) __linux__ && !__ANDROID__ 355 // Darwin (macOS and iOS) __APPLE__ 356 // Akaros (http://akaros.org) __ros__ 357 // Windows _WIN32 358 // NaCL __native_client__ 359 // AsmJS __asmjs__ 360 // WebAssembly __wasm__ 361 // Fuchsia __Fuchsia__ 362 // 363 // Note that since Android defines both __ANDROID__ and __linux__, one 364 // may probe for either Linux or Android by simply testing for __linux__. 365 366 // ABSL_HAVE_MMAP 367 // 368 // Checks whether the platform has an mmap(2) implementation as defined in 369 // POSIX.1-2001. 370 #ifdef ABSL_HAVE_MMAP 371 #error ABSL_HAVE_MMAP cannot be directly set 372 #elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \ 373 defined(__ros__) || defined(__native_client__) || defined(__asmjs__) || \ 374 defined(__wasm__) || defined(__Fuchsia__) || defined(__sun) || \ 375 defined(__ASYLO__) || defined(__myriad2__) 376 #define ABSL_HAVE_MMAP 1 377 #endif 378 379 // ABSL_HAVE_PTHREAD_GETSCHEDPARAM 380 // 381 // Checks whether the platform implements the pthread_(get|set)schedparam(3) 382 // functions as defined in POSIX.1-2001. 383 #ifdef ABSL_HAVE_PTHREAD_GETSCHEDPARAM 384 #error ABSL_HAVE_PTHREAD_GETSCHEDPARAM cannot be directly set 385 #elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \ 386 defined(__ros__) 387 #define ABSL_HAVE_PTHREAD_GETSCHEDPARAM 1 388 #endif 389 390 // ABSL_HAVE_SCHED_GETCPU 391 // 392 // Checks whether sched_getcpu is available. 393 #ifdef ABSL_HAVE_SCHED_GETCPU 394 #error ABSL_HAVE_SCHED_GETCPU cannot be directly set 395 #elif defined(__linux__) 396 #define ABSL_HAVE_SCHED_GETCPU 1 397 #endif 398 399 // ABSL_HAVE_SCHED_YIELD 400 // 401 // Checks whether the platform implements sched_yield(2) as defined in 402 // POSIX.1-2001. 403 #ifdef ABSL_HAVE_SCHED_YIELD 404 #error ABSL_HAVE_SCHED_YIELD cannot be directly set 405 #elif defined(__linux__) || defined(__ros__) || defined(__native_client__) 406 #define ABSL_HAVE_SCHED_YIELD 1 407 #endif 408 409 // ABSL_HAVE_SEMAPHORE_H 410 // 411 // Checks whether the platform supports the <semaphore.h> header and sem_init(3) 412 // family of functions as standardized in POSIX.1-2001. 413 // 414 // Note: While Apple provides <semaphore.h> for both iOS and macOS, it is 415 // explicitly deprecated and will cause build failures if enabled for those 416 // platforms. We side-step the issue by not defining it here for Apple 417 // platforms. 418 #ifdef ABSL_HAVE_SEMAPHORE_H 419 #error ABSL_HAVE_SEMAPHORE_H cannot be directly set 420 #elif defined(__linux__) || defined(__ros__) 421 #define ABSL_HAVE_SEMAPHORE_H 1 422 #endif 423 424 // ABSL_HAVE_ALARM 425 // 426 // Checks whether the platform supports the <signal.h> header and alarm(2) 427 // function as standardized in POSIX.1-2001. 428 #ifdef ABSL_HAVE_ALARM 429 #error ABSL_HAVE_ALARM cannot be directly set 430 #elif defined(__GOOGLE_GRTE_VERSION__) 431 // feature tests for Google's GRTE 432 #define ABSL_HAVE_ALARM 1 433 #elif defined(__GLIBC__) 434 // feature test for glibc 435 #define ABSL_HAVE_ALARM 1 436 #elif defined(_MSC_VER) 437 // feature tests for Microsoft's library 438 #elif defined(__MINGW32__) 439 // mingw32 doesn't provide alarm(2): 440 // https://osdn.net/projects/mingw/scm/git/mingw-org-wsl/blobs/5.2-trunk/mingwrt/include/unistd.h 441 // mingw-w64 provides a no-op implementation: 442 // https://sourceforge.net/p/mingw-w64/mingw-w64/ci/master/tree/mingw-w64-crt/misc/alarm.c 443 #elif defined(__EMSCRIPTEN__) 444 // emscripten doesn't support signals 445 #elif defined(__Fuchsia__) 446 // Signals don't exist on fuchsia. 447 #elif defined(__native_client__) 448 #else 449 // other standard libraries 450 #define ABSL_HAVE_ALARM 1 451 #endif 452 453 // ABSL_IS_LITTLE_ENDIAN 454 // ABSL_IS_BIG_ENDIAN 455 // 456 // Checks the endianness of the platform. 457 // 458 // Notes: uses the built in endian macros provided by GCC (since 4.6) and 459 // Clang (since 3.2); see 460 // https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html. 461 // Otherwise, if _WIN32, assume little endian. Otherwise, bail with an error. 462 #if defined(ABSL_IS_BIG_ENDIAN) 463 #error "ABSL_IS_BIG_ENDIAN cannot be directly set." 464 #endif 465 #if defined(ABSL_IS_LITTLE_ENDIAN) 466 #error "ABSL_IS_LITTLE_ENDIAN cannot be directly set." 467 #endif 468 469 #if (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && \ 470 __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) 471 #define ABSL_IS_LITTLE_ENDIAN 1 472 #elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \ 473 __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ 474 #define ABSL_IS_BIG_ENDIAN 1 475 #elif defined(_WIN32) 476 #define ABSL_IS_LITTLE_ENDIAN 1 477 #else 478 #error "absl endian detection needs to be set up for your compiler" 479 #endif 480 481 // macOS 10.13 and iOS 10.11 don't let you use <any>, <optional>, or <variant> 482 // even though the headers exist and are publicly noted to work. See 483 // https://github.com/abseil/abseil-cpp/issues/207 and 484 // https://developer.apple.com/documentation/xcode_release_notes/xcode_10_release_notes 485 // libc++ spells out the availability requirements in the file 486 // llvm-project/libcxx/include/__config via the #define 487 // _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS. 488 #if defined(__APPLE__) && defined(_LIBCPP_VERSION) && \ 489 ((defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && \ 490 __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101400) || \ 491 (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && \ 492 __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 120000) || \ 493 (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && \ 494 __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 50000) || \ 495 (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && \ 496 __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 120000)) 497 #define ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 1 498 #else 499 #define ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 0 500 #endif 501 502 // ABSL_HAVE_STD_ANY 503 // 504 // Checks whether C++17 std::any is available by checking whether <any> exists. 505 #ifdef ABSL_HAVE_STD_ANY 506 #error "ABSL_HAVE_STD_ANY cannot be directly set." 507 #endif 508 509 #ifdef __has_include 510 #if __has_include(<any>) && defined(__cplusplus) && __cplusplus >= 201703L && \ 511 !ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 512 #define ABSL_HAVE_STD_ANY 1 513 #endif 514 #endif 515 516 // ABSL_HAVE_STD_OPTIONAL 517 // 518 // Checks whether C++17 std::optional is available. 519 #ifdef ABSL_HAVE_STD_OPTIONAL 520 #error "ABSL_HAVE_STD_OPTIONAL cannot be directly set." 521 #endif 522 523 #ifdef __has_include 524 #if __has_include(<optional>) && defined(__cplusplus) && \ 525 __cplusplus >= 201703L && !ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 526 #define ABSL_HAVE_STD_OPTIONAL 1 527 #endif 528 #endif 529 530 // ABSL_HAVE_STD_VARIANT 531 // 532 // Checks whether C++17 std::variant is available. 533 #ifdef ABSL_HAVE_STD_VARIANT 534 #error "ABSL_HAVE_STD_VARIANT cannot be directly set." 535 #endif 536 537 #ifdef __has_include 538 #if __has_include(<variant>) && defined(__cplusplus) && \ 539 __cplusplus >= 201703L && !ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 540 #define ABSL_HAVE_STD_VARIANT 1 541 #endif 542 #endif 543 544 // ABSL_HAVE_STD_STRING_VIEW 545 // 546 // Checks whether C++17 std::string_view is available. 547 #ifdef ABSL_HAVE_STD_STRING_VIEW 548 #error "ABSL_HAVE_STD_STRING_VIEW cannot be directly set." 549 #endif 550 551 #ifdef __has_include 552 #if __has_include(<string_view>) && defined(__cplusplus) && \ 553 __cplusplus >= 201703L 554 #define ABSL_HAVE_STD_STRING_VIEW 1 555 #endif 556 #endif 557 558 // For MSVC, `__has_include` is supported in VS 2017 15.3, which is later than 559 // the support for <optional>, <any>, <string_view>, <variant>. So we use 560 // _MSC_VER to check whether we have VS 2017 RTM (when <optional>, <any>, 561 // <string_view>, <variant> is implemented) or higher. Also, `__cplusplus` is 562 // not correctly set by MSVC, so we use `_MSVC_LANG` to check the language 563 // version. 564 // TODO(zhangxy): fix tests before enabling aliasing for `std::any`. 565 #if defined(_MSC_VER) && _MSC_VER >= 1910 && \ 566 ((defined(_MSVC_LANG) && _MSVC_LANG > 201402) || \ 567 (defined(__cplusplus) && __cplusplus > 201402)) 568 // #define ABSL_HAVE_STD_ANY 1 569 #define ABSL_HAVE_STD_OPTIONAL 1 570 #define ABSL_HAVE_STD_VARIANT 1 571 #define ABSL_HAVE_STD_STRING_VIEW 1 572 #endif 573 574 // ABSL_USES_STD_ANY 575 // 576 // Indicates whether absl::any is an alias for std::any. 577 #if !defined(ABSL_OPTION_USE_STD_ANY) 578 #error options.h is misconfigured. 579 #elif ABSL_OPTION_USE_STD_ANY == 0 || \ 580 (ABSL_OPTION_USE_STD_ANY == 2 && !defined(ABSL_HAVE_STD_ANY)) 581 #undef ABSL_USES_STD_ANY 582 #elif ABSL_OPTION_USE_STD_ANY == 1 || \ 583 (ABSL_OPTION_USE_STD_ANY == 2 && defined(ABSL_HAVE_STD_ANY)) 584 #define ABSL_USES_STD_ANY 1 585 #else 586 #error options.h is misconfigured. 587 #endif 588 589 // ABSL_USES_STD_OPTIONAL 590 // 591 // Indicates whether absl::optional is an alias for std::optional. 592 #if !defined(ABSL_OPTION_USE_STD_OPTIONAL) 593 #error options.h is misconfigured. 594 #elif ABSL_OPTION_USE_STD_OPTIONAL == 0 || \ 595 (ABSL_OPTION_USE_STD_OPTIONAL == 2 && !defined(ABSL_HAVE_STD_OPTIONAL)) 596 #undef ABSL_USES_STD_OPTIONAL 597 #elif ABSL_OPTION_USE_STD_OPTIONAL == 1 || \ 598 (ABSL_OPTION_USE_STD_OPTIONAL == 2 && defined(ABSL_HAVE_STD_OPTIONAL)) 599 #define ABSL_USES_STD_OPTIONAL 1 600 #else 601 #error options.h is misconfigured. 602 #endif 603 604 // ABSL_USES_STD_VARIANT 605 // 606 // Indicates whether absl::variant is an alias for std::variant. 607 #if !defined(ABSL_OPTION_USE_STD_VARIANT) 608 #error options.h is misconfigured. 609 #elif ABSL_OPTION_USE_STD_VARIANT == 0 || \ 610 (ABSL_OPTION_USE_STD_VARIANT == 2 && !defined(ABSL_HAVE_STD_VARIANT)) 611 #undef ABSL_USES_STD_VARIANT 612 #elif ABSL_OPTION_USE_STD_VARIANT == 1 || \ 613 (ABSL_OPTION_USE_STD_VARIANT == 2 && defined(ABSL_HAVE_STD_VARIANT)) 614 #define ABSL_USES_STD_VARIANT 1 615 #else 616 #error options.h is misconfigured. 617 #endif 618 619 // ABSL_USES_STD_STRING_VIEW 620 // 621 // Indicates whether absl::string_view is an alias for std::string_view. 622 #if !defined(ABSL_OPTION_USE_STD_STRING_VIEW) 623 #error options.h is misconfigured. 624 #elif ABSL_OPTION_USE_STD_STRING_VIEW == 0 || \ 625 (ABSL_OPTION_USE_STD_STRING_VIEW == 2 && \ 626 !defined(ABSL_HAVE_STD_STRING_VIEW)) 627 #undef ABSL_USES_STD_STRING_VIEW 628 #elif ABSL_OPTION_USE_STD_STRING_VIEW == 1 || \ 629 (ABSL_OPTION_USE_STD_STRING_VIEW == 2 && \ 630 defined(ABSL_HAVE_STD_STRING_VIEW)) 631 #define ABSL_USES_STD_STRING_VIEW 1 632 #else 633 #error options.h is misconfigured. 634 #endif 635 636 // In debug mode, MSVC 2017's std::variant throws a EXCEPTION_ACCESS_VIOLATION 637 // SEH exception from emplace for variant<SomeStruct> when constructing the 638 // struct can throw. This defeats some of variant_test and 639 // variant_exception_safety_test. 640 #if defined(_MSC_VER) && _MSC_VER >= 1700 && defined(_DEBUG) 641 #define ABSL_INTERNAL_MSVC_2017_DBG_MODE 642 #endif 643 644 // ABSL_INTERNAL_MANGLED_NS 645 // ABSL_INTERNAL_MANGLED_BACKREFERENCE 646 // 647 // Internal macros for building up mangled names in our internal fork of CCTZ. 648 // This implementation detail is only needed and provided for the MSVC build. 649 // 650 // These macros both expand to string literals. ABSL_INTERNAL_MANGLED_NS is 651 // the mangled spelling of the `absl` namespace, and 652 // ABSL_INTERNAL_MANGLED_BACKREFERENCE is a back-reference integer representing 653 // the proper count to skip past the CCTZ fork namespace names. (This number 654 // is one larger when there is an inline namespace name to skip.) 655 #if defined(_MSC_VER) 656 #if ABSL_OPTION_USE_INLINE_NAMESPACE == 0 657 #define ABSL_INTERNAL_MANGLED_NS "absl" 658 #define ABSL_INTERNAL_MANGLED_BACKREFERENCE "5" 659 #else 660 #define ABSL_INTERNAL_MANGLED_NS \ 661 ABSL_INTERNAL_TOKEN_STR(ABSL_OPTION_INLINE_NAMESPACE_NAME) "@absl" 662 #define ABSL_INTERNAL_MANGLED_BACKREFERENCE "6" 663 #endif 664 #endif 665 666 #undef ABSL_INTERNAL_HAS_KEYWORD 667 668 // ABSL_DLL 669 // 670 // When building Abseil as a DLL, this macro expands to `__declspec(dllexport)` 671 // so we can annotate symbols appropriately as being exported. When used in 672 // headers consuming a DLL, this macro expands to `__declspec(dllimport)` so 673 // that consumers know the symbol is defined inside the DLL. In all other cases, 674 // the macro expands to nothing. 675 #if defined(_MSC_VER) 676 #if defined(ABSL_BUILD_DLL) 677 #define ABSL_DLL __declspec(dllexport) 678 #elif defined(ABSL_CONSUME_DLL) 679 #define ABSL_DLL __declspec(dllimport) 680 #else 681 #define ABSL_DLL 682 #endif 683 #else 684 #define ABSL_DLL 685 #endif // defined(_MSC_VER) 686 687 // ABSL_HAVE_MEMORY_SANITIZER 688 // 689 // MemorySanitizer (MSan) is a detector of uninitialized reads. It consists of 690 // a compiler instrumentation module and a run-time library. 691 #ifdef ABSL_HAVE_MEMORY_SANITIZER 692 #error "ABSL_HAVE_MEMORY_SANITIZER cannot be directly set." 693 #elif defined(MEMORY_SANITIZER) 694 // The MEMORY_SANITIZER macro is deprecated but we will continue to honor it 695 // for now. 696 #define ABSL_HAVE_MEMORY_SANITIZER 1 697 #elif defined(__SANITIZE_MEMORY__) 698 #define ABSL_HAVE_MEMORY_SANITIZER 1 699 #elif !defined(__native_client__) && ABSL_HAVE_FEATURE(memory_sanitizer) 700 #define ABSL_HAVE_MEMORY_SANITIZER 1 701 #endif 702 703 // ABSL_HAVE_THREAD_SANITIZER 704 // 705 // ThreadSanitizer (TSan) is a fast data race detector. 706 #ifdef ABSL_HAVE_THREAD_SANITIZER 707 #error "ABSL_HAVE_THREAD_SANITIZER cannot be directly set." 708 #elif defined(THREAD_SANITIZER) 709 // The THREAD_SANITIZER macro is deprecated but we will continue to honor it 710 // for now. 711 #define ABSL_HAVE_THREAD_SANITIZER 1 712 #elif defined(__SANITIZE_THREAD__) 713 #define ABSL_HAVE_THREAD_SANITIZER 1 714 #elif ABSL_HAVE_FEATURE(thread_sanitizer) 715 #define ABSL_HAVE_THREAD_SANITIZER 1 716 #endif 717 718 // ABSL_HAVE_ADDRESS_SANITIZER 719 // 720 // AddressSanitizer (ASan) is a fast memory error detector. 721 #ifdef ABSL_HAVE_ADDRESS_SANITIZER 722 #error "ABSL_HAVE_ADDRESS_SANITIZER cannot be directly set." 723 #elif defined(ADDRESS_SANITIZER) 724 // The ADDRESS_SANITIZER macro is deprecated but we will continue to honor it 725 // for now. 726 #define ABSL_HAVE_ADDRESS_SANITIZER 1 727 #elif defined(__SANITIZE_ADDRESS__) 728 #define ABSL_HAVE_ADDRESS_SANITIZER 1 729 #elif ABSL_HAVE_FEATURE(address_sanitizer) 730 #define ABSL_HAVE_ADDRESS_SANITIZER 1 731 #endif 732 733 // ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION 734 // 735 // Class template argument deduction is a language feature added in C++17. 736 #ifdef ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION 737 #error "ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION cannot be directly set." 738 #elif defined(__cpp_deduction_guides) 739 #define ABSL_HAVE_CLASS_TEMPLATE_ARGUMENT_DEDUCTION 1 740 #endif 741 742 #endif // ABSL_BASE_CONFIG_H_ 743