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 #elif ABSL_OPTION_USE_INLINE_NAMESPACE == 1 125 #define ABSL_NAMESPACE_BEGIN \ 126 inline namespace ABSL_OPTION_INLINE_NAMESPACE_NAME { 127 #define ABSL_NAMESPACE_END } 128 #else 129 #error options.h is misconfigured. 130 #endif 131 132 // ----------------------------------------------------------------------------- 133 // Compiler Feature Checks 134 // ----------------------------------------------------------------------------- 135 136 // ABSL_HAVE_BUILTIN() 137 // 138 // Checks whether the compiler supports a Clang Feature Checking Macro, and if 139 // so, checks whether it supports the provided builtin function "x" where x 140 // is one of the functions noted in 141 // https://clang.llvm.org/docs/LanguageExtensions.html 142 // 143 // Note: Use this macro to avoid an extra level of #ifdef __has_builtin check. 144 // http://releases.llvm.org/3.3/tools/clang/docs/LanguageExtensions.html 145 #ifdef __has_builtin 146 #define ABSL_HAVE_BUILTIN(x) __has_builtin(x) 147 #else 148 #define ABSL_HAVE_BUILTIN(x) 0 149 #endif 150 151 #if defined(__is_identifier) 152 #define ABSL_INTERNAL_HAS_KEYWORD(x) !(__is_identifier(x)) 153 #else 154 #define ABSL_INTERNAL_HAS_KEYWORD(x) 0 155 #endif 156 157 // ABSL_HAVE_TLS is defined to 1 when __thread should be supported. 158 // We assume __thread is supported on Linux when compiled with Clang or compiled 159 // against libstdc++ with _GLIBCXX_HAVE_TLS defined. 160 #ifdef ABSL_HAVE_TLS 161 #error ABSL_HAVE_TLS cannot be directly set 162 #elif defined(__linux__) && (defined(__clang__) || defined(_GLIBCXX_HAVE_TLS)) 163 #define ABSL_HAVE_TLS 1 164 #endif 165 166 // ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE 167 // 168 // Checks whether `std::is_trivially_destructible<T>` is supported. 169 // 170 // Notes: All supported compilers using libc++ support this feature, as does 171 // gcc >= 4.8.1 using libstdc++, and Visual Studio. 172 #ifdef ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE 173 #error ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE cannot be directly set 174 #elif defined(_LIBCPP_VERSION) || \ 175 (!defined(__clang__) && defined(__GNUC__) && defined(__GLIBCXX__) && \ 176 (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) || \ 177 defined(_MSC_VER) 178 #define ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE 1 179 #endif 180 181 // ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE 182 // 183 // Checks whether `std::is_trivially_default_constructible<T>` and 184 // `std::is_trivially_copy_constructible<T>` are supported. 185 186 // ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE 187 // 188 // Checks whether `std::is_trivially_copy_assignable<T>` is supported. 189 190 // Notes: Clang with libc++ supports these features, as does gcc >= 5.1 with 191 // either libc++ or libstdc++, and Visual Studio (but not NVCC). 192 #if defined(ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE) 193 #error ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE cannot be directly set 194 #elif defined(ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE) 195 #error ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE cannot directly set 196 #elif (defined(__clang__) && defined(_LIBCPP_VERSION)) || \ 197 (!defined(__clang__) && defined(__GNUC__) && \ 198 (__GNUC__ > 7 || (__GNUC__ == 7 && __GNUC_MINOR__ >= 4)) && \ 199 (defined(_LIBCPP_VERSION) || defined(__GLIBCXX__))) || \ 200 (defined(_MSC_VER) && !defined(__NVCC__)) 201 #define ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE 1 202 #define ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE 1 203 #endif 204 205 // ABSL_HAVE_SOURCE_LOCATION_CURRENT 206 // 207 // Indicates whether `absl::SourceLocation::current()` will return useful 208 // information in some contexts. 209 #ifndef ABSL_HAVE_SOURCE_LOCATION_CURRENT 210 #if ABSL_INTERNAL_HAS_KEYWORD(__builtin_LINE) && \ 211 ABSL_INTERNAL_HAS_KEYWORD(__builtin_FILE) 212 #define ABSL_HAVE_SOURCE_LOCATION_CURRENT 1 213 #endif 214 #endif 215 216 // ABSL_HAVE_THREAD_LOCAL 217 // 218 // Checks whether C++11's `thread_local` storage duration specifier is 219 // supported. 220 #ifdef ABSL_HAVE_THREAD_LOCAL 221 #error ABSL_HAVE_THREAD_LOCAL cannot be directly set 222 #elif defined(__APPLE__) 223 // Notes: 224 // * Xcode's clang did not support `thread_local` until version 8, and 225 // even then not for all iOS < 9.0. 226 // * Xcode 9.3 started disallowing `thread_local` for 32-bit iOS simulator 227 // targeting iOS 9.x. 228 // * Xcode 10 moves the deployment target check for iOS < 9.0 to link time 229 // making __has_feature unreliable there. 230 // 231 // Otherwise, `__has_feature` is only supported by Clang so it has be inside 232 // `defined(__APPLE__)` check. 233 #if __has_feature(cxx_thread_local) && \ 234 !(TARGET_OS_IPHONE && __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_9_0) 235 #define ABSL_HAVE_THREAD_LOCAL 1 236 #endif 237 #else // !defined(__APPLE__) 238 #define ABSL_HAVE_THREAD_LOCAL 1 239 #endif 240 241 // There are platforms for which TLS should not be used even though the compiler 242 // makes it seem like it's supported (Android NDK < r12b for example). 243 // This is primarily because of linker problems and toolchain misconfiguration: 244 // Abseil does not intend to support this indefinitely. Currently, the newest 245 // toolchain that we intend to support that requires this behavior is the 246 // r11 NDK - allowing for a 5 year support window on that means this option 247 // is likely to be removed around June of 2021. 248 // TLS isn't supported until NDK r12b per 249 // https://developer.android.com/ndk/downloads/revision_history.html 250 // Since NDK r16, `__NDK_MAJOR__` and `__NDK_MINOR__` are defined in 251 // <android/ndk-version.h>. For NDK < r16, users should define these macros, 252 // e.g. `-D__NDK_MAJOR__=11 -D__NKD_MINOR__=0` for NDK r11. 253 #if defined(__ANDROID__) && defined(__clang__) 254 #if __has_include(<android/ndk-version.h>) 255 #include <android/ndk-version.h> 256 #endif // __has_include(<android/ndk-version.h>) 257 #if defined(__ANDROID__) && defined(__clang__) && defined(__NDK_MAJOR__) && \ 258 defined(__NDK_MINOR__) && \ 259 ((__NDK_MAJOR__ < 12) || ((__NDK_MAJOR__ == 12) && (__NDK_MINOR__ < 1))) 260 #undef ABSL_HAVE_TLS 261 #undef ABSL_HAVE_THREAD_LOCAL 262 #endif 263 #endif // defined(__ANDROID__) && defined(__clang__) 264 265 // ABSL_HAVE_INTRINSIC_INT128 266 // 267 // Checks whether the __int128 compiler extension for a 128-bit integral type is 268 // supported. 269 // 270 // Note: __SIZEOF_INT128__ is defined by Clang and GCC when __int128 is 271 // supported, but we avoid using it in certain cases: 272 // * On Clang: 273 // * Building using Clang for Windows, where the Clang runtime library has 274 // 128-bit support only on LP64 architectures, but Windows is LLP64. 275 // * On Nvidia's nvcc: 276 // * nvcc also defines __GNUC__ and __SIZEOF_INT128__, but not all versions 277 // actually support __int128. 278 #ifdef ABSL_HAVE_INTRINSIC_INT128 279 #error ABSL_HAVE_INTRINSIC_INT128 cannot be directly set 280 #elif defined(__SIZEOF_INT128__) 281 #if (defined(__clang__) && !defined(_WIN32)) || \ 282 (defined(__CUDACC__) && __CUDACC_VER_MAJOR__ >= 9) || \ 283 (defined(__GNUC__) && !defined(__clang__) && !defined(__CUDACC__)) 284 #define ABSL_HAVE_INTRINSIC_INT128 1 285 #elif defined(__CUDACC__) 286 // __CUDACC_VER__ is a full version number before CUDA 9, and is defined to a 287 // string explaining that it has been removed starting with CUDA 9. We use 288 // nested #ifs because there is no short-circuiting in the preprocessor. 289 // NOTE: `__CUDACC__` could be undefined while `__CUDACC_VER__` is defined. 290 #if __CUDACC_VER__ >= 70000 291 #define ABSL_HAVE_INTRINSIC_INT128 1 292 #endif // __CUDACC_VER__ >= 70000 293 #endif // defined(__CUDACC__) 294 #endif // ABSL_HAVE_INTRINSIC_INT128 295 296 // ABSL_HAVE_EXCEPTIONS 297 // 298 // Checks whether the compiler both supports and enables exceptions. Many 299 // compilers support a "no exceptions" mode that disables exceptions. 300 // 301 // Generally, when ABSL_HAVE_EXCEPTIONS is not defined: 302 // 303 // * Code using `throw` and `try` may not compile. 304 // * The `noexcept` specifier will still compile and behave as normal. 305 // * The `noexcept` operator may still return `false`. 306 // 307 // For further details, consult the compiler's documentation. 308 #ifdef ABSL_HAVE_EXCEPTIONS 309 #error ABSL_HAVE_EXCEPTIONS cannot be directly set. 310 311 #elif defined(__clang__) 312 313 #if __clang_major__ > 3 || (__clang_major__ == 3 && __clang_minor__ >= 6) 314 // Clang >= 3.6 315 #if __has_feature(cxx_exceptions) 316 #define ABSL_HAVE_EXCEPTIONS 1 317 #endif // __has_feature(cxx_exceptions) 318 #else 319 // Clang < 3.6 320 // http://releases.llvm.org/3.6.0/tools/clang/docs/ReleaseNotes.html#the-exceptions-macro 321 #if defined(__EXCEPTIONS) && __has_feature(cxx_exceptions) 322 #define ABSL_HAVE_EXCEPTIONS 1 323 #endif // defined(__EXCEPTIONS) && __has_feature(cxx_exceptions) 324 #endif // __clang_major__ > 3 || (__clang_major__ == 3 && __clang_minor__ >= 6) 325 326 // Handle remaining special cases and default to exceptions being supported. 327 #elif !(defined(__GNUC__) && (__GNUC__ < 5) && !defined(__EXCEPTIONS)) && \ 328 !(defined(__GNUC__) && (__GNUC__ >= 5) && !defined(__cpp_exceptions)) && \ 329 !(defined(_MSC_VER) && !defined(_CPPUNWIND)) 330 #define ABSL_HAVE_EXCEPTIONS 1 331 #endif 332 333 // ----------------------------------------------------------------------------- 334 // Platform Feature Checks 335 // ----------------------------------------------------------------------------- 336 337 // Currently supported operating systems and associated preprocessor 338 // symbols: 339 // 340 // Linux and Linux-derived __linux__ 341 // Android __ANDROID__ (implies __linux__) 342 // Linux (non-Android) __linux__ && !__ANDROID__ 343 // Darwin (macOS and iOS) __APPLE__ 344 // Akaros (http://akaros.org) __ros__ 345 // Windows _WIN32 346 // NaCL __native_client__ 347 // AsmJS __asmjs__ 348 // WebAssembly __wasm__ 349 // Fuchsia __Fuchsia__ 350 // 351 // Note that since Android defines both __ANDROID__ and __linux__, one 352 // may probe for either Linux or Android by simply testing for __linux__. 353 354 // ABSL_HAVE_MMAP 355 // 356 // Checks whether the platform has an mmap(2) implementation as defined in 357 // POSIX.1-2001. 358 #ifdef ABSL_HAVE_MMAP 359 #error ABSL_HAVE_MMAP cannot be directly set 360 #elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \ 361 defined(__ros__) || defined(__native_client__) || defined(__asmjs__) || \ 362 defined(__wasm__) || defined(__Fuchsia__) || defined(__sun) || \ 363 defined(__ASYLO__) 364 #define ABSL_HAVE_MMAP 1 365 #endif 366 367 // ABSL_HAVE_PTHREAD_GETSCHEDPARAM 368 // 369 // Checks whether the platform implements the pthread_(get|set)schedparam(3) 370 // functions as defined in POSIX.1-2001. 371 #ifdef ABSL_HAVE_PTHREAD_GETSCHEDPARAM 372 #error ABSL_HAVE_PTHREAD_GETSCHEDPARAM cannot be directly set 373 #elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \ 374 defined(__ros__) 375 #define ABSL_HAVE_PTHREAD_GETSCHEDPARAM 1 376 #endif 377 378 // ABSL_HAVE_SCHED_YIELD 379 // 380 // Checks whether the platform implements sched_yield(2) as defined in 381 // POSIX.1-2001. 382 #ifdef ABSL_HAVE_SCHED_YIELD 383 #error ABSL_HAVE_SCHED_YIELD cannot be directly set 384 #elif defined(__linux__) || defined(__ros__) || defined(__native_client__) 385 #define ABSL_HAVE_SCHED_YIELD 1 386 #endif 387 388 // ABSL_HAVE_SEMAPHORE_H 389 // 390 // Checks whether the platform supports the <semaphore.h> header and sem_init(3) 391 // family of functions as standardized in POSIX.1-2001. 392 // 393 // Note: While Apple provides <semaphore.h> for both iOS and macOS, it is 394 // explicitly deprecated and will cause build failures if enabled for those 395 // platforms. We side-step the issue by not defining it here for Apple 396 // platforms. 397 #ifdef ABSL_HAVE_SEMAPHORE_H 398 #error ABSL_HAVE_SEMAPHORE_H cannot be directly set 399 #elif defined(__linux__) || defined(__ros__) 400 #define ABSL_HAVE_SEMAPHORE_H 1 401 #endif 402 403 // ABSL_HAVE_ALARM 404 // 405 // Checks whether the platform supports the <signal.h> header and alarm(2) 406 // function as standardized in POSIX.1-2001. 407 #ifdef ABSL_HAVE_ALARM 408 #error ABSL_HAVE_ALARM cannot be directly set 409 #elif defined(__GOOGLE_GRTE_VERSION__) 410 // feature tests for Google's GRTE 411 #define ABSL_HAVE_ALARM 1 412 #elif defined(__GLIBC__) 413 // feature test for glibc 414 #define ABSL_HAVE_ALARM 1 415 #elif defined(_MSC_VER) 416 // feature tests for Microsoft's library 417 #elif defined(__MINGW32__) 418 // mingw32 doesn't provide alarm(2): 419 // https://osdn.net/projects/mingw/scm/git/mingw-org-wsl/blobs/5.2-trunk/mingwrt/include/unistd.h 420 // mingw-w64 provides a no-op implementation: 421 // https://sourceforge.net/p/mingw-w64/mingw-w64/ci/master/tree/mingw-w64-crt/misc/alarm.c 422 #elif defined(__EMSCRIPTEN__) 423 // emscripten doesn't support signals 424 #elif defined(__Fuchsia__) 425 // Signals don't exist on fuchsia. 426 #elif defined(__native_client__) 427 #else 428 // other standard libraries 429 #define ABSL_HAVE_ALARM 1 430 #endif 431 432 // ABSL_IS_LITTLE_ENDIAN 433 // ABSL_IS_BIG_ENDIAN 434 // 435 // Checks the endianness of the platform. 436 // 437 // Notes: uses the built in endian macros provided by GCC (since 4.6) and 438 // Clang (since 3.2); see 439 // https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html. 440 // Otherwise, if _WIN32, assume little endian. Otherwise, bail with an error. 441 #if defined(ABSL_IS_BIG_ENDIAN) 442 #error "ABSL_IS_BIG_ENDIAN cannot be directly set." 443 #endif 444 #if defined(ABSL_IS_LITTLE_ENDIAN) 445 #error "ABSL_IS_LITTLE_ENDIAN cannot be directly set." 446 #endif 447 448 #if (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && \ 449 __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) 450 #define ABSL_IS_LITTLE_ENDIAN 1 451 #elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \ 452 __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ 453 #define ABSL_IS_BIG_ENDIAN 1 454 #elif defined(_WIN32) 455 #define ABSL_IS_LITTLE_ENDIAN 1 456 #else 457 #error "absl endian detection needs to be set up for your compiler" 458 #endif 459 460 // macOS 10.13 and iOS 10.11 don't let you use <any>, <optional>, or <variant> 461 // even though the headers exist and are publicly noted to work. See 462 // https://github.com/abseil/abseil-cpp/issues/207 and 463 // https://developer.apple.com/documentation/xcode_release_notes/xcode_10_release_notes 464 // libc++ spells out the availability requirements in the file 465 // llvm-project/libcxx/include/__config via the #define 466 // _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS. 467 #if defined(__APPLE__) && defined(_LIBCPP_VERSION) && \ 468 ((defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && \ 469 __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101400) || \ 470 (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && \ 471 __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 120000) || \ 472 (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && \ 473 __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 120000) || \ 474 (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && \ 475 __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 50000)) 476 #define ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 1 477 #else 478 #define ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 0 479 #endif 480 481 // ABSL_HAVE_STD_ANY 482 // 483 // Checks whether C++17 std::any is available by checking whether <any> exists. 484 #ifdef ABSL_HAVE_STD_ANY 485 #error "ABSL_HAVE_STD_ANY cannot be directly set." 486 #endif 487 488 #ifdef __has_include 489 #if __has_include(<any>) && __cplusplus >= 201703L && \ 490 !ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 491 #define ABSL_HAVE_STD_ANY 1 492 #endif 493 #endif 494 495 // ABSL_HAVE_STD_OPTIONAL 496 // 497 // Checks whether C++17 std::optional is available. 498 #ifdef ABSL_HAVE_STD_OPTIONAL 499 #error "ABSL_HAVE_STD_OPTIONAL cannot be directly set." 500 #endif 501 502 #ifdef __has_include 503 #if __has_include(<optional>) && __cplusplus >= 201703L && \ 504 !ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 505 #define ABSL_HAVE_STD_OPTIONAL 1 506 #endif 507 #endif 508 509 // ABSL_HAVE_STD_VARIANT 510 // 511 // Checks whether C++17 std::variant is available. 512 #ifdef ABSL_HAVE_STD_VARIANT 513 #error "ABSL_HAVE_STD_VARIANT cannot be directly set." 514 #endif 515 516 #ifdef __has_include 517 #if __has_include(<variant>) && __cplusplus >= 201703L && \ 518 !ABSL_INTERNAL_APPLE_CXX17_TYPES_UNAVAILABLE 519 #define ABSL_HAVE_STD_VARIANT 1 520 #endif 521 #endif 522 523 // ABSL_HAVE_STD_STRING_VIEW 524 // 525 // Checks whether C++17 std::string_view is available. 526 #ifdef ABSL_HAVE_STD_STRING_VIEW 527 #error "ABSL_HAVE_STD_STRING_VIEW cannot be directly set." 528 #endif 529 530 #ifdef __has_include 531 #if __has_include(<string_view>) && __cplusplus >= 201703L 532 #define ABSL_HAVE_STD_STRING_VIEW 1 533 #endif 534 #endif 535 536 // For MSVC, `__has_include` is supported in VS 2017 15.3, which is later than 537 // the support for <optional>, <any>, <string_view>, <variant>. So we use 538 // _MSC_VER to check whether we have VS 2017 RTM (when <optional>, <any>, 539 // <string_view>, <variant> is implemented) or higher. Also, `__cplusplus` is 540 // not correctly set by MSVC, so we use `_MSVC_LANG` to check the language 541 // version. 542 // TODO(zhangxy): fix tests before enabling aliasing for `std::any`. 543 #if defined(_MSC_VER) && _MSC_VER >= 1910 && \ 544 ((defined(_MSVC_LANG) && _MSVC_LANG > 201402) || __cplusplus > 201402) 545 // #define ABSL_HAVE_STD_ANY 1 546 #define ABSL_HAVE_STD_OPTIONAL 1 547 #define ABSL_HAVE_STD_VARIANT 1 548 #define ABSL_HAVE_STD_STRING_VIEW 1 549 #endif 550 551 // ABSL_USES_STD_ANY 552 // 553 // Indicates whether absl::any is an alias for std::any. 554 #if !defined(ABSL_OPTION_USE_STD_ANY) 555 #error options.h is misconfigured. 556 #elif ABSL_OPTION_USE_STD_ANY == 0 || \ 557 (ABSL_OPTION_USE_STD_ANY == 2 && !defined(ABSL_HAVE_STD_ANY)) 558 #undef ABSL_USES_STD_ANY 559 #elif ABSL_OPTION_USE_STD_ANY == 1 || \ 560 (ABSL_OPTION_USE_STD_ANY == 2 && defined(ABSL_HAVE_STD_ANY)) 561 #define ABSL_USES_STD_ANY 1 562 #else 563 #error options.h is misconfigured. 564 #endif 565 566 // ABSL_USES_STD_OPTIONAL 567 // 568 // Indicates whether absl::optional is an alias for std::optional. 569 #if !defined(ABSL_OPTION_USE_STD_OPTIONAL) 570 #error options.h is misconfigured. 571 #elif ABSL_OPTION_USE_STD_OPTIONAL == 0 || \ 572 (ABSL_OPTION_USE_STD_OPTIONAL == 2 && !defined(ABSL_HAVE_STD_OPTIONAL)) 573 #undef ABSL_USES_STD_OPTIONAL 574 #elif ABSL_OPTION_USE_STD_OPTIONAL == 1 || \ 575 (ABSL_OPTION_USE_STD_OPTIONAL == 2 && defined(ABSL_HAVE_STD_OPTIONAL)) 576 #define ABSL_USES_STD_OPTIONAL 1 577 #else 578 #error options.h is misconfigured. 579 #endif 580 581 // ABSL_USES_STD_VARIANT 582 // 583 // Indicates whether absl::variant is an alias for std::variant. 584 #if !defined(ABSL_OPTION_USE_STD_VARIANT) 585 #error options.h is misconfigured. 586 #elif ABSL_OPTION_USE_STD_VARIANT == 0 || \ 587 (ABSL_OPTION_USE_STD_VARIANT == 2 && !defined(ABSL_HAVE_STD_VARIANT)) 588 #undef ABSL_USES_STD_VARIANT 589 #elif ABSL_OPTION_USE_STD_VARIANT == 1 || \ 590 (ABSL_OPTION_USE_STD_VARIANT == 2 && defined(ABSL_HAVE_STD_VARIANT)) 591 #define ABSL_USES_STD_VARIANT 1 592 #else 593 #error options.h is misconfigured. 594 #endif 595 596 // ABSL_USES_STD_STRING_VIEW 597 // 598 // Indicates whether absl::string_view is an alias for std::string_view. 599 #if !defined(ABSL_OPTION_USE_STD_STRING_VIEW) 600 #error options.h is misconfigured. 601 #elif ABSL_OPTION_USE_STD_STRING_VIEW == 0 || \ 602 (ABSL_OPTION_USE_STD_STRING_VIEW == 2 && \ 603 !defined(ABSL_HAVE_STD_STRING_VIEW)) 604 #undef ABSL_USES_STD_STRING_VIEW 605 #elif ABSL_OPTION_USE_STD_STRING_VIEW == 1 || \ 606 (ABSL_OPTION_USE_STD_STRING_VIEW == 2 && \ 607 defined(ABSL_HAVE_STD_STRING_VIEW)) 608 #define ABSL_USES_STD_STRING_VIEW 1 609 #else 610 #error options.h is misconfigured. 611 #endif 612 613 // In debug mode, MSVC 2017's std::variant throws a EXCEPTION_ACCESS_VIOLATION 614 // SEH exception from emplace for variant<SomeStruct> when constructing the 615 // struct can throw. This defeats some of variant_test and 616 // variant_exception_safety_test. 617 #if defined(_MSC_VER) && _MSC_VER >= 1700 && defined(_DEBUG) 618 #define ABSL_INTERNAL_MSVC_2017_DBG_MODE 619 #endif 620 621 // ABSL_INTERNAL_MANGLED_NS 622 // ABSL_INTERNAL_MANGLED_BACKREFERENCE 623 // 624 // Internal macros for building up mangled names in our internal fork of CCTZ. 625 // This implementation detail is only needed and provided for the MSVC build. 626 // 627 // These macros both expand to string literals. ABSL_INTERNAL_MANGLED_NS is 628 // the mangled spelling of the `absl` namespace, and 629 // ABSL_INTERNAL_MANGLED_BACKREFERENCE is a back-reference integer representing 630 // the proper count to skip past the CCTZ fork namespace names. (This number 631 // is one larger when there is an inline namespace name to skip.) 632 #if defined(_MSC_VER) 633 #if ABSL_OPTION_USE_INLINE_NAMESPACE == 0 634 #define ABSL_INTERNAL_MANGLED_NS "absl" 635 #define ABSL_INTERNAL_MANGLED_BACKREFERENCE "5" 636 #else 637 #define ABSL_INTERNAL_MANGLED_NS \ 638 ABSL_INTERNAL_TOKEN_STR(ABSL_OPTION_INLINE_NAMESPACE_NAME) "@absl" 639 #define ABSL_INTERNAL_MANGLED_BACKREFERENCE "6" 640 #endif 641 #endif 642 643 #undef ABSL_INTERNAL_HAS_KEYWORD 644 645 // ABSL_DLL 646 // 647 // When building Abseil as a DLL, this macro expands to `__declspec(dllexport)` 648 // so we can annotate symbols appropriately as being exported. When used in 649 // headers consuming a DLL, this macro expands to `__declspec(dllimport)` so 650 // that consumers know the symbol is defined inside the DLL. In all other cases, 651 // the macro expands to nothing. 652 #if defined(_MSC_VER) 653 #if defined(ABSL_BUILD_DLL) 654 #define ABSL_DLL __declspec(dllexport) 655 #elif defined(ABSL_CONSUME_DLL) 656 #define ABSL_DLL __declspec(dllimport) 657 #else 658 #define ABSL_DLL 659 #endif 660 #else 661 #define ABSL_DLL 662 #endif // defined(_MSC_VER) 663 664 #endif // ABSL_BASE_CONFIG_H_ 665