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