444 lines
16 KiB
C
444 lines
16 KiB
C
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//
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// Copyright 2017 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// -----------------------------------------------------------------------------
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// File: config.h
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// -----------------------------------------------------------------------------
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//
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// This header file defines a set of macros for checking the presence of
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// important compiler and platform features. Such macros can be used to
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// produce portable code by parameterizing compilation based on the presence or
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// lack of a given feature.
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//
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// We define a "feature" as some interface we wish to program to: for example,
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// a library function or system call. A value of `1` indicates support for
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// that feature; any other value indicates the feature support is undefined.
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//
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// Example:
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//
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// Suppose a programmer wants to write a program that uses the 'mmap()' system
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// call. The Abseil macro for that feature (`ABSL_HAVE_MMAP`) allows you to
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// selectively include the `mmap.h` header and bracket code using that feature
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// in the macro:
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//
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// #include "absl/base/config.h"
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//
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// #ifdef ABSL_HAVE_MMAP
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// #include "sys/mman.h"
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// #endif //ABSL_HAVE_MMAP
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//
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// ...
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// #ifdef ABSL_HAVE_MMAP
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// void *ptr = mmap(...);
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// ...
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// #endif // ABSL_HAVE_MMAP
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#ifndef ABSL_BASE_CONFIG_H_
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#define ABSL_BASE_CONFIG_H_
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// Included for the __GLIBC__ macro (or similar macros on other systems).
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#include <limits.h>
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#ifdef __cplusplus
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// Included for __GLIBCXX__, _LIBCPP_VERSION
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#include <cstddef>
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#endif // __cplusplus
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#if defined(__APPLE__)
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// Included for TARGET_OS_IPHONE, __IPHONE_OS_VERSION_MIN_REQUIRED,
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// __IPHONE_8_0.
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#include <Availability.h>
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#include <TargetConditionals.h>
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#endif
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#include "absl/base/policy_checks.h"
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// -----------------------------------------------------------------------------
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// Compiler Feature Checks
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// -----------------------------------------------------------------------------
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// ABSL_HAVE_BUILTIN()
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//
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// Checks whether the compiler supports a Clang Feature Checking Macro, and if
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// so, checks whether it supports the provided builtin function "x" where x
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// is one of the functions noted in
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// https://clang.llvm.org/docs/LanguageExtensions.html
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//
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// Note: Use this macro to avoid an extra level of #ifdef __has_builtin check.
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// http://releases.llvm.org/3.3/tools/clang/docs/LanguageExtensions.html
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#ifdef __has_builtin
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#define ABSL_HAVE_BUILTIN(x) __has_builtin(x)
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#else
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#define ABSL_HAVE_BUILTIN(x) 0
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#endif
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// ABSL_HAVE_TLS is defined to 1 when __thread should be supported.
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// We assume __thread is supported on Linux when compiled with Clang or compiled
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// against libstdc++ with _GLIBCXX_HAVE_TLS defined.
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#ifdef ABSL_HAVE_TLS
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#error ABSL_HAVE_TLS cannot be directly set
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#elif defined(__linux__) && (defined(__clang__) || defined(_GLIBCXX_HAVE_TLS))
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#define ABSL_HAVE_TLS 1
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#endif
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// ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE
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//
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// Checks whether `std::is_trivially_destructible<T>` is supported.
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//
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// Notes: All supported compilers using libc++ support this feature, as does
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// gcc >= 4.8.1 using libstdc++, and Visual Studio.
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#ifdef ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE
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#error ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE cannot be directly set
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#elif defined(_LIBCPP_VERSION) || \
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(!defined(__clang__) && defined(__GNUC__) && defined(__GLIBCXX__) && \
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(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) || \
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defined(_MSC_VER)
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#define ABSL_HAVE_STD_IS_TRIVIALLY_DESTRUCTIBLE 1
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#endif
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// ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE
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//
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// Checks whether `std::is_trivially_default_constructible<T>` and
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// `std::is_trivially_copy_constructible<T>` are supported.
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// ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE
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//
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// Checks whether `std::is_trivially_copy_assignable<T>` is supported.
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// Notes: Clang with libc++ supports these features, as does gcc >= 5.1 with
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// either libc++ or libstdc++, and Visual Studio.
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#if defined(ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE)
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#error ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE cannot be directly set
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#elif defined(ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE)
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#error ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE cannot directly set
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#elif (defined(__clang__) && defined(_LIBCPP_VERSION)) || \
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(!defined(__clang__) && defined(__GNUC__) && \
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(__GNUC__ > 5 || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)) && \
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(defined(_LIBCPP_VERSION) || defined(__GLIBCXX__))) || \
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defined(_MSC_VER)
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#define ABSL_HAVE_STD_IS_TRIVIALLY_CONSTRUCTIBLE 1
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#define ABSL_HAVE_STD_IS_TRIVIALLY_ASSIGNABLE 1
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#endif
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// ABSL_HAVE_THREAD_LOCAL
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//
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// Checks whether C++11's `thread_local` storage duration specifier is
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// supported.
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#ifdef ABSL_HAVE_THREAD_LOCAL
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#error ABSL_HAVE_THREAD_LOCAL cannot be directly set
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#elif defined(__APPLE__)
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// Notes:
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// * Xcode's clang did not support `thread_local` until version 8, and
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// even then not for all iOS < 9.0.
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// * Xcode 9.3 started disallowing `thread_local` for 32-bit iOS simulator
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// targeting iOS 9.x.
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// * Xcode 10 moves the deployment target check for iOS < 9.0 to link time
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// making __has_feature unreliable there.
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//
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// Otherwise, `__has_feature` is only supported by Clang so it has be inside
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// `defined(__APPLE__)` check.
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#if __has_feature(cxx_thread_local) && \
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!(TARGET_OS_IPHONE && __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_9_0)
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#define ABSL_HAVE_THREAD_LOCAL 1
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#endif
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#else // !defined(__APPLE__)
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#define ABSL_HAVE_THREAD_LOCAL 1
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#endif
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// There are platforms for which TLS should not be used even though the compiler
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// makes it seem like it's supported (Android NDK < r12b for example).
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// This is primarily because of linker problems and toolchain misconfiguration:
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// Abseil does not intend to support this indefinitely. Currently, the newest
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// toolchain that we intend to support that requires this behavior is the
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// r11 NDK - allowing for a 5 year support window on that means this option
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// is likely to be removed around June of 2021.
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// TLS isn't supported until NDK r12b per
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// https://developer.android.com/ndk/downloads/revision_history.html
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// Since NDK r16, `__NDK_MAJOR__` and `__NDK_MINOR__` are defined in
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// <android/ndk-version.h>. For NDK < r16, users should define these macros,
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// e.g. `-D__NDK_MAJOR__=11 -D__NKD_MINOR__=0` for NDK r11.
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#if defined(__ANDROID__) && defined(__clang__)
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#if __has_include(<android/ndk-version.h>)
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#include <android/ndk-version.h>
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#endif // __has_include(<android/ndk-version.h>)
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#if defined(__ANDROID__) && defined(__clang__) && defined(__NDK_MAJOR__) && \
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defined(__NDK_MINOR__) && \
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((__NDK_MAJOR__ < 12) || ((__NDK_MAJOR__ == 12) && (__NDK_MINOR__ < 1)))
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#undef ABSL_HAVE_TLS
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#undef ABSL_HAVE_THREAD_LOCAL
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#endif
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#endif // defined(__ANDROID__) && defined(__clang__)
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// ABSL_HAVE_INTRINSIC_INT128
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//
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// Checks whether the __int128 compiler extension for a 128-bit integral type is
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// supported.
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//
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// Note: __SIZEOF_INT128__ is defined by Clang and GCC when __int128 is
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// supported, but we avoid using it in certain cases:
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// * On Clang:
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// * Building using Clang for Windows, where the Clang runtime library has
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// 128-bit support only on LP64 architectures, but Windows is LLP64.
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// * Building for aarch64, where __int128 exists but has exhibits a sporadic
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// compiler crashing bug.
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// * On Nvidia's nvcc:
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// * nvcc also defines __GNUC__ and __SIZEOF_INT128__, but not all versions
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// actually support __int128.
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#ifdef ABSL_HAVE_INTRINSIC_INT128
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#error ABSL_HAVE_INTRINSIC_INT128 cannot be directly set
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#elif defined(__SIZEOF_INT128__)
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#if (defined(__clang__) && !defined(_WIN32) && !defined(__aarch64__)) || \
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(defined(__CUDACC__) && __CUDACC_VER_MAJOR__ >= 9) || \
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(defined(__GNUC__) && !defined(__clang__) && !defined(__CUDACC__))
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#define ABSL_HAVE_INTRINSIC_INT128 1
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#elif defined(__CUDACC__)
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// __CUDACC_VER__ is a full version number before CUDA 9, and is defined to a
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// string explaining that it has been removed starting with CUDA 9. We use
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// nested #ifs because there is no short-circuiting in the preprocessor.
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// NOTE: `__CUDACC__` could be undefined while `__CUDACC_VER__` is defined.
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#if __CUDACC_VER__ >= 70000
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#define ABSL_HAVE_INTRINSIC_INT128 1
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#endif // __CUDACC_VER__ >= 70000
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#endif // defined(__CUDACC__)
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#endif // ABSL_HAVE_INTRINSIC_INT128
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// ABSL_HAVE_EXCEPTIONS
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//
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// Checks whether the compiler both supports and enables exceptions. Many
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// compilers support a "no exceptions" mode that disables exceptions.
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//
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// Generally, when ABSL_HAVE_EXCEPTIONS is not defined:
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//
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// * Code using `throw` and `try` may not compile.
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// * The `noexcept` specifier will still compile and behave as normal.
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// * The `noexcept` operator may still return `false`.
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//
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// For further details, consult the compiler's documentation.
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#ifdef ABSL_HAVE_EXCEPTIONS
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#error ABSL_HAVE_EXCEPTIONS cannot be directly set.
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#elif defined(__clang__)
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// TODO(calabrese)
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// Switch to using __cpp_exceptions when we no longer support versions < 3.6.
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// For details on this check, see:
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// http://releases.llvm.org/3.6.0/tools/clang/docs/ReleaseNotes.html#the-exceptions-macro
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#if defined(__EXCEPTIONS) && __has_feature(cxx_exceptions)
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#define ABSL_HAVE_EXCEPTIONS 1
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#endif // defined(__EXCEPTIONS) && __has_feature(cxx_exceptions)
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// Handle remaining special cases and default to exceptions being supported.
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#elif !(defined(__GNUC__) && (__GNUC__ < 5) && !defined(__EXCEPTIONS)) && \
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!(defined(__GNUC__) && (__GNUC__ >= 5) && !defined(__cpp_exceptions)) && \
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!(defined(_MSC_VER) && !defined(_CPPUNWIND))
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#define ABSL_HAVE_EXCEPTIONS 1
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#endif
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// -----------------------------------------------------------------------------
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// Platform Feature Checks
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// -----------------------------------------------------------------------------
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// Currently supported operating systems and associated preprocessor
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// symbols:
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//
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// Linux and Linux-derived __linux__
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// Android __ANDROID__ (implies __linux__)
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// Linux (non-Android) __linux__ && !__ANDROID__
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// Darwin (Mac OS X and iOS) __APPLE__
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// Akaros (http://akaros.org) __ros__
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// Windows _WIN32
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// NaCL __native_client__
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// AsmJS __asmjs__
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// WebAssembly __wasm__
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// Fuchsia __Fuchsia__
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//
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// Note that since Android defines both __ANDROID__ and __linux__, one
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// may probe for either Linux or Android by simply testing for __linux__.
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// ABSL_HAVE_MMAP
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//
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// Checks whether the platform has an mmap(2) implementation as defined in
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// POSIX.1-2001.
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#ifdef ABSL_HAVE_MMAP
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#error ABSL_HAVE_MMAP cannot be directly set
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#elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \
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defined(__ros__) || defined(__native_client__) || defined(__asmjs__) || \
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defined(__wasm__) || defined(__Fuchsia__) || defined(__sun) || \
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defined(__ASYLO__)
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#define ABSL_HAVE_MMAP 1
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#endif
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// ABSL_HAVE_PTHREAD_GETSCHEDPARAM
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//
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// Checks whether the platform implements the pthread_(get|set)schedparam(3)
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// functions as defined in POSIX.1-2001.
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#ifdef ABSL_HAVE_PTHREAD_GETSCHEDPARAM
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#error ABSL_HAVE_PTHREAD_GETSCHEDPARAM cannot be directly set
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#elif defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) || \
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defined(__ros__)
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#define ABSL_HAVE_PTHREAD_GETSCHEDPARAM 1
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#endif
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// ABSL_HAVE_SCHED_YIELD
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//
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// Checks whether the platform implements sched_yield(2) as defined in
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// POSIX.1-2001.
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#ifdef ABSL_HAVE_SCHED_YIELD
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#error ABSL_HAVE_SCHED_YIELD cannot be directly set
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#elif defined(__linux__) || defined(__ros__) || defined(__native_client__)
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#define ABSL_HAVE_SCHED_YIELD 1
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#endif
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// ABSL_HAVE_SEMAPHORE_H
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//
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// Checks whether the platform supports the <semaphore.h> header and sem_open(3)
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// family of functions as standardized in POSIX.1-2001.
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//
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// Note: While Apple provides <semaphore.h> for both iOS and macOS, it is
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// explicitly deprecated and will cause build failures if enabled for those
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// platforms. We side-step the issue by not defining it here for Apple
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// platforms.
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#ifdef ABSL_HAVE_SEMAPHORE_H
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#error ABSL_HAVE_SEMAPHORE_H cannot be directly set
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#elif defined(__linux__) || defined(__ros__)
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#define ABSL_HAVE_SEMAPHORE_H 1
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#endif
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// ABSL_HAVE_ALARM
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//
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// Checks whether the platform supports the <signal.h> header and alarm(2)
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// function as standardized in POSIX.1-2001.
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#ifdef ABSL_HAVE_ALARM
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#error ABSL_HAVE_ALARM cannot be directly set
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#elif defined(__GOOGLE_GRTE_VERSION__)
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// feature tests for Google's GRTE
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#define ABSL_HAVE_ALARM 1
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#elif defined(__GLIBC__)
|
||
|
|
// feature test for glibc
|
||
|
|
#define ABSL_HAVE_ALARM 1
|
||
|
|
#elif defined(_MSC_VER)
|
||
|
|
// feature tests for Microsoft's library
|
||
|
|
#elif defined(__EMSCRIPTEN__)
|
||
|
|
// emscripten doesn't support signals
|
||
|
|
#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::variant 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`.
|
||
|
|
#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
|
||
|
|
|
||
|
|
// In debug mode, MSVC 2017's std::variant throws a EXCEPTION_ACCESS_VIOLATION
|
||
|
|
// SEH exception from emplace for variant<SomeStruct> when constructing the
|
||
|
|
// struct can throw. This defeats some of variant_test and
|
||
|
|
// variant_exception_safety_test.
|
||
|
|
#if defined(_MSC_VER) && _MSC_VER >= 1700 && defined(_DEBUG)
|
||
|
|
#define ABSL_INTERNAL_MSVC_2017_DBG_MODE
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#endif // ABSL_BASE_CONFIG_H_
|