libc/src/time/linux/nanosleep.cpp

   1 //===-- Linux implementation of nanosleep function ------------------------===//
   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 #include "src/time/nanosleep.h"
  10
  11 #include "src/__support/OSUtil/syscall.h" // For syscall functions.
  12 #include "src/__support/common.h"
  13 #include "src/errno/libc_errno.h"
  14
  15 #include <stdint.h>      // For int64_t.
  16 #include <sys/syscall.h> // For syscall numbers.
  17
  18 namespace LIBC_NAMESPACE {
  19
  20 LLVM_LIBC_FUNCTION(int, nanosleep,
  21                    (const struct timespec *req, struct timespec *rem)) {
  22 #if SYS_nanosleep
  23   int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_nanosleep, req, rem);
  24 #elif defined(SYS_clock_nanosleep_time64)
  25   static_assert(
  26       sizeof(time_t) == sizeof(int64_t),
  27       "SYS_clock_gettime64 requires struct timespec with 64-bit members.");
  28   int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_nanosleep_time64,
  29                                               CLOCK_REALTIME, 0, req, rem);
  30 #else
  31 #error "SYS_nanosleep and SYS_clock_nanosleep_time64 syscalls not available."
  32 #endif
  33
  34   if (ret < 0) {
  35     libc_errno = -ret;
  36     return -1;
  37   }
  38   return ret;
  39 }
  40
  41 } // namespace LIBC_NAMESPACE