libc/src/__support/threads/linux/futex_word.h

   1 //===--- Definition of a type for a futex word ------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_LIBC_SRC___SUPPORT_THREADS_LINUX_FUTEX_WORD_H
  10 #define LLVM_LIBC_SRC___SUPPORT_THREADS_LINUX_FUTEX_WORD_H
  11
  12 #include "src/__support/macros/config.h"
  13 #include <stdint.h>
  14 #include <sys/syscall.h>
  15 namespace LIBC_NAMESPACE_DECL {
  16
  17 // Futexes are 32 bits in size on all platforms, including 64-bit platforms.
  18 using FutexWordType = uint32_t;
  19
  20 #if SYS_futex
  21 constexpr auto FUTEX_SYSCALL_ID = SYS_futex;
  22 #elif defined(SYS_futex_time64)
  23 constexpr auto FUTEX_SYSCALL_ID = SYS_futex_time64;
  24 #else
  25 #error "futex and futex_time64 syscalls not available."
  26 #endif
  27
  28 } // namespace LIBC_NAMESPACE_DECL
  29
  30 #endif // LLVM_LIBC_SRC___SUPPORT_THREADS_LINUX_FUTEX_WORD_H