// // Copyright 2017 The Abseil Authors. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // // ----------------------------------------------------------------------------- // File: config.h // ----------------------------------------------------------------------------- // // This header file defines a set of macros for checking the presence of // important compiler and platform features. Such macros can be used to // produce portable code by parameterizing compilation based on the presence or // lack of a given feature. // // We define a "feature" as some interface we wish to program to: for example, // a library function or system call. A value of `1` indicates support for // that feature; any other value indicates the feature support is undefined. // // Example: // // Suppose a programmer wants to write a program that uses the 'mmap()' system // call. The Abseil macro for that feature (`ABSL_HAVE_MMAP`) allows you to // selectively include the `mmap.h` header and bracket code using that feature // in the macro: // // #include "absl/base/config.h" // // #ifdef ABSL_HAVE_MMAP // #include "sys/mman.h" // #endif //ABSL_HAVE_MMAP // // ... // #ifdef ABSL_HAVE_MMAP // void *ptr = mmap(...); // ... // #endif // ABSL_HAVE_MMAP #ifndef ABSL_BASE_CONFIG_H_ #define ABSL_BASE_CONFIG_H_ // Included for the __GLIBC__ macro (or similar macros on other systems). #include <limits.h> #ifdef __cplusplus // Included for __GLIBCXX__, _LIBCPP_VERSION #include <cstddef> #endif // __cplusplus #if defined(__APPLE__) // Included for TARGET_OS_IPHONE, __IPHONE_OS_VERSION_MIN_REQUIRED, // __IPHONE_8_0. #include <Availability.h> #include <TargetConditionals.h> #endif #include "absl/base/policy_checks.h" // ----------------------------------------------------------------------------- // Compiler Feature Checks // ----------------------------------------------------------------------------- // ABSL_HAVE_BUILTIN() // // Checks whether the compiler supports a Clang Feature Checking Macro, and if // so, checks whether it supports the provided builtin function "x" where x // is one of the functions noted in // https://clang.llvm.org/docs/LanguageExtensions.html // // Note: Use this macro to avoid an extra level of #ifdef __has_builtin check. // http://releases.llvm.org/3.3/tools/clang/docs/LanguageExtensions.html #ifdef __has_builtin #define ABSL_HAVE_BUILTIN(x) __has_builtin(x) #else #define ABSL_HAVE_BUILTIN(x) 0 #endif // ABSL_HAVE_TLS is defined to 1 when __thread should be supported. // We assume __thread is supported on Linux when compiled with Clang or compiled // against libstdc++ with _GLIBCXX_HAVE_TLS defined. #ifdef ABSL_HAVE_TLS #error ABSL_HAVE_TLS cannot be directly set #elif defined(__linux__) && (defined(__clang__) || defined(_GLIBCXX_HAVE_TLS)) #define ABSL_HAVE_TLS 1 #endif // ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE // // Checks whether `std::is_trivially_destructible<T>` is supported. // // Notes: All supported compilers using libc++ support this feature, as does // gcc >= 4.8.1 using libstdc++, and Visual Studio. #ifdef ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE #error ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE cannot be directly set #elif defined(_LIBCPP_VERSION) || \ (!defined(__clang__) && defined(__GNUC__) && defined(__GLIBCXX__) && \ (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) || \ defined(_MSC_VER) #define ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE 1 #endif // ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE // // Checks whether `std::is_trivially_default_constructible<T>` and // `std::is_trivially_copy_constructible<T>` are supported. // ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE // // Checks whether `std::is_trivially_copy_assignable<T>` is supported. // Notes: Clang with libc++ supports these features, as does gcc >= 5.1 with // either libc++ or libstdc++, and Visual Studio. #if defined(ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE) #error ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE cannot be directly set #elif defined(ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE) #error ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE cannot directly set #elif (defined(__clang__) && defined(_LIBCPP_VERSION)) || \ (!defined(__clang__) && defined(__GNUC__) && \ (__GNUC__ > 5 || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)) && \ (defined(_LIBCPP_VERSION) || defined(__GLIBCXX__))) || \ defined(_MSC_VER) #define ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE 1 #define ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE 1 #endif // ABSL_HAVE_THREAD_LOCAL // // Checks whether C++11's `thread_local` storage duration specifier is // supported. #ifdef ABSL_HAVE_THREAD_LOCAL #error ABSL_HAVE_THREAD_LOCAL cannot be directly set #elif defined(__APPLE__) // Notes: Xcode's clang did not support `thread_local` until version // 8, and even then not for all iOS < 9.0. Also, Xcode 9.3 started disallowing // `thread_local` for 32-bit iOS simulator targeting iOS 9.x. // `__has_feature` is only supported by Clang so it has be inside // `defined(__APPLE__)` check. #if __has_feature(cxx_thread_local) #define ABSL_HAVE_THREAD_LOCAL 1 #endif #else // !defined(__APPLE__) #define ABSL_HAVE_THREAD_LOCAL 1 #endif // There are platforms for which TLS should not be used even though the compiler // makes it seem like it's supported (Android NDK < r12b for example). // This is primarily because of linker problems and toolchain misconfiguration: // Abseil does not intend to support this indefinitely. Currently, the newest // toolchain that we intend to support that requires this behavior is the // r11 NDK - allowing for a 5 year support window on that means this option // is likely to be removed around June of 2021. // TLS isn't supported until NDK r12b per // https://developer.android.com/ndk/downloads/revision_history.html // Since NDK r16, `__NDK_MAJOR__` and `__NDK_MINOR__` are defined in // <android/ndk-version.h>. For NDK < r16, users should define these macros, // e.g. `-D__NDK_MAJOR__=11 -D__NKD_MINOR__=0` for NDK r11. #if defined(__ANDROID__) && defined(__clang__) #if __has_include(<android/ndk-version.h>) #include <android/ndk-version.h> #endif // __has_include(<android/ndk-version.h>) #if defined(__ANDROID__) && defined(__clang__) && defined(__NDK_MAJOR__) && \ defined(__NDK_MINOR__) && \ ((__NDK_MAJOR__ < 12) || ((__NDK_MAJOR__ == 12) && (__NDK_MINOR__ < 1))) #undef ABSL_HAVE_TLS #undef ABSL_HAVE_THREAD_LOCAL #endif #endif // defined(__ANDROID__) && defined(__clang__) // ABSL_HAVE_INTRINSIC_INT128 // // Checks whether the __int128 compiler extension for a 128-bit integral type is // supported. // // Note: __SIZEOF_INT128__ is defined by Clang and GCC when __int128 is // supported, but we avoid using it in certain cases: // * On Clang: // * Building using Clang for Windows, where the Clang runtime library has // 128-bit support only on LP64 architectures, but Windows is LLP64. // * Building for aarch64, where __int128 exists but has exhibits a sporadic // compiler crashing bug. // * On Nvidia's nvcc: // * nvcc also defines __GNUC__ and __SIZEOF_INT128__, but not all versions // actually support __int128. #ifdef ABSL_HAVE_INTRINSIC_INT128 #error ABSL_HAVE_INTRINSIC_INT128 cannot be directly set #elif defined(__SIZEOF_INT128__) #if (defined(__clang__) && !defined(_WIN32) && !defined(__aarch64__)) || \ (defined(__CUDACC__) && __CUDACC_VER_MAJOR__ >= 9) || \ (defined(__GNUC__) && !defined(__clang__) && !defined(__CUDACC__)) #define ABSL_HAVE_INTRINSIC_INT128 1 #elif defined(__CUDACC__) // __CUDACC_VER__ is a full version number before CUDA 9, and is defined to a // std::string explaining that it has been removed starting with CUDA 9. We use // nested #ifs because there is no short-circuiting in the preprocessor. // NOTE: `__CUDACC__` could be undefined while `__CUDACC_VER__` is defined. #if __CUDACC_VER__ >= 70000 #define ABSL_HAVE_INTRINSIC_INT128 1 #endif // __CUDACC_VER__ >= 70000 #endif // defined(__CUDACC__) #endif // ABSL_HAVE_INTRINSIC_INT128 // ABSL_HAVE_EXCEPTIONS // // Checks whether the compiler both supports and enables exceptions. Many // compilers support a "no exceptions" mode that disables exceptions. // // Generally, when ABSL_HAVE_EXCEPTIONS is not defined: // // * Code using `throw` and `try` may not compile. // * The `noexcept` specifier will still compile and behave as normal. // * The `noexcept` operator may still return `false`. // // For further details, consult the compiler's documentation. #ifdef ABSL_HAVE_EXCEPTIONS #error ABSL_HAVE_EXCEPTIONS cannot be directly set. #elif defined(__clang__) // TODO(calabrese) // Switch to using __cpp_exceptions when we no longer support versions < 3.6. // For details on this check, see: // http://releases.llvm.org/3.6.0/tools/clang/docs/ReleaseNotes.html#the-exceptions-macro #if defined(__EXCEPTIONS) && __has_feature(cxx_exceptions) #define ABSL_HAVE_EXCEPTIONS 1 #endif // defined(__EXCEPTIONS) && __has_feature(cxx_exceptions) // Handle remaining special cases and default to exceptions being supported. #elif !(defined(__GNUC__) && (__GNUC__ < 5) && !defined(__EXCEPTIONS)) && \ !(defined(__GNUC__) && (__GNUC__ >= 5) && !defined(__cpp_exceptions)) && \ !(defined(_MSC_VER) && !defined(_CPPUNWIND)) #define ABSL_HAVE_EXCEPTIONS 1 #endif // ----------------------------------------------------------------------------- // Platform Feature Checks // ----------------------------------------------------------------------------- // Currently supported operating systems and associated preprocessor // symbols: // // Linux and Linux-derived __linux__ // Android __ANDROID__ (implies __linux__) // Linux (non-Android) __linux__ && !__ANDROID__ // Darwin (Mac OS X and iOS) __APPLE__ // Akaros (http://akaros.org) __ros__ // Windows _WIN32 // NaCL __native_client__ // AsmJS __asmjs__ // WebAssembly __wasm__ // Fuchsia __Fuchsia__ // // Note that since Android defines both __ANDROID__ and __linux__, one // may probe for either Linux or Android by simply testing for __linux__. // ABSL_HAVE_MMAP // // Checks whether the platform has an mmap(2) implementation as defined in // POSIX.1-2001. #ifdef ABSL_HAVE_MMAP #error ABSL_HAVE_MMAP cannot be directly set #elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \ defined(__ros__) || defined(__native_client__) || defined(__asmjs__) || \ defined(__wasm__) || defined(__Fuchsia__) #define ABSL_HAVE_MMAP 1 #endif // ABSL_HAVE_PTHREAD_GETSCHEDPARAM // // Checks whether the platform implements the pthread_(get|set)schedparam(3) // functions as defined in POSIX.1-2001. #ifdef ABSL_HAVE_PTHREAD_GETSCHEDPARAM #error ABSL_HAVE_PTHREAD_GETSCHEDPARAM cannot be directly set #elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \ defined(__ros__) #define ABSL_HAVE_PTHREAD_GETSCHEDPARAM 1 #endif // ABSL_HAVE_SCHED_YIELD // // Checks whether the platform implements sched_yield(2) as defined in // POSIX.1-2001. #ifdef ABSL_HAVE_SCHED_YIELD #error ABSL_HAVE_SCHED_YIELD cannot be directly set #elif defined(__linux__) || defined(__ros__) || defined(__native_client__) #define ABSL_HAVE_SCHED_YIELD 1 #endif // ABSL_HAVE_SEMAPHORE_H // // Checks whether the platform supports the <semaphore.h> header and sem_open(3) // family of functions as standardized in POSIX.1-2001. // // Note: While Apple provides <semaphore.h> for both iOS and macOS, it is // explicitly deprecated and will cause build failures if enabled for those // platforms. We side-step the issue by not defining it here for Apple // platforms. #ifdef ABSL_HAVE_SEMAPHORE_H #error ABSL_HAVE_SEMAPHORE_H cannot be directly set #elif defined(__linux__) || defined(__ros__) #define ABSL_HAVE_SEMAPHORE_H 1 #endif // ABSL_HAVE_ALARM // // Checks whether the platform supports the <signal.h> header and alarm(2) // function as standardized in POSIX.1-2001. #ifdef ABSL_HAVE_ALARM #error ABSL_HAVE_ALARM cannot be directly set #elif defined(__GOOGLE_GRTE_VERSION__) // feature tests for Google's GRTE #define ABSL_HAVE_ALARM 1 #elif defined(__GLIBC__) // feature test for glibc #define ABSL_HAVE_ALARM 1 #elif defined(_MSC_VER) // feature tests for Microsoft's library #elif defined(__native_client__) #else // other standard libraries #define ABSL_HAVE_ALARM 1 #endif // ABSL_IS_LITTLE_ENDIAN // ABSL_IS_BIG_ENDIAN // // Checks the endianness of the platform. // // Notes: uses the built in endian macros provided by GCC (since 4.6) and // Clang (since 3.2); see // https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html. // Otherwise, if _WIN32, assume little endian. Otherwise, bail with an error. #if defined(ABSL_IS_BIG_ENDIAN) #error "ABSL_IS_BIG_ENDIAN cannot be directly set." #endif #if defined(ABSL_IS_LITTLE_ENDIAN) #error "ABSL_IS_LITTLE_ENDIAN cannot be directly set." #endif #if (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && \ __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) #define ABSL_IS_LITTLE_ENDIAN 1 #elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \ __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ #define ABSL_IS_BIG_ENDIAN 1 #elif defined(_WIN32) #define ABSL_IS_LITTLE_ENDIAN 1 #else #error "absl endian detection needs to be set up for your compiler" #endif // ABSL_HAVE_STD_ANY // // Checks whether C++17 std::any is available by checking whether <any> exists. #ifdef ABSL_HAVE_STD_ANY #error "ABSL_HAVE_STD_ANY cannot be directly set." #endif #ifdef __has_include #if __has_include(<any>) && __cplusplus >= 201703L #define ABSL_HAVE_STD_ANY 1 #endif #endif // ABSL_HAVE_STD_OPTIONAL // // Checks whether C++17 std::optional is available. #ifdef ABSL_HAVE_STD_OPTIONAL #error "ABSL_HAVE_STD_OPTIONAL cannot be directly set." #endif #ifdef __has_include #if __has_include(<optional>) && __cplusplus >= 201703L #define ABSL_HAVE_STD_OPTIONAL 1 #endif #endif // ABSL_HAVE_STD_VARIANT // // Checks whether C++17 std::optional is available. #ifdef ABSL_HAVE_STD_VARIANT #error "ABSL_HAVE_STD_VARIANT cannot be directly set." #endif #ifdef __has_include #if __has_include(<variant>) && __cplusplus >= 201703L #define ABSL_HAVE_STD_VARIANT 1 #endif #endif // ABSL_HAVE_STD_STRING_VIEW // // Checks whether C++17 std::string_view is available. #ifdef ABSL_HAVE_STD_STRING_VIEW #error "ABSL_HAVE_STD_STRING_VIEW cannot be directly set." #endif #ifdef __has_include #if __has_include(<string_view>) && __cplusplus >= 201703L #define ABSL_HAVE_STD_STRING_VIEW 1 #endif #endif // For MSVC, `__has_include` is supported in VS 2017 15.3, which is later than // the support for <optional>, <any>, <string_view>, <variant>. So we use // _MSC_VER to check whether we have VS 2017 RTM (when <optional>, <any>, // <string_view>, <variant> is implemented) or higher. Also, `__cplusplus` is // not correctly set by MSVC, so we use `_MSVC_LANG` to check the language // version. // TODO(zhangxy): fix tests before enabling aliasing for `std::any`, // `std::string_view`. #if defined(_MSC_VER) && _MSC_VER >= 1910 && \ ((defined(_MSVC_LANG) && _MSVC_LANG > 201402) || __cplusplus > 201402) // #define ABSL_HAVE_STD_ANY 1 #define ABSL_HAVE_STD_OPTIONAL 1 #define ABSL_HAVE_STD_VARIANT 1 // #define ABSL_HAVE_STD_STRING_VIEW 1 #endif #endif // ABSL_BASE_CONFIG_H_