| //===-- Linux futex related definitions -------------------------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_LIBC_SRC_THREADS_LINUX_FUTEX_H |
| #define LLVM_LIBC_SRC_THREADS_LINUX_FUTEX_H |
| |
| #include <stdatomic.h> |
| |
| namespace __llvm_libc { |
| |
| // The futex data has to be exactly 4 bytes long. However, we use a uint type |
| // here as we do not want to use `_Atomic uint32_t` as the _Atomic keyword which |
| // is C only. The header stdatomic.h does not define an atomic type |
| // corresponding to `uint32_t` or to something which is exactly 4 bytes wide. |
| using FutexWord = atomic_uint; |
| static_assert(sizeof(atomic_uint) == 4, |
| "Size of the `atomic_uint` type is not 4 bytes on your platform. " |
| "The implementation of the standard threads library for linux " |
| "requires that size of `atomic_uint` be 4 bytes."); |
| |
| } // namespace __llvm_libc |
| |
| #endif // LLVM_LIBC_SRC_THREADS_LINUX_FUTEX_H |
