libc/src/time/clock_gettime.cpp

   1 //===---------- Linux implementation of the POSIX clock_gettime 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/clock_gettime.h"
  10
  11 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
  12 #include "src/__support/common.h"
  13 #include "src/errno/libc_errno.h"
  14
  15 #include <sys/syscall.h> // For syscall numbers.
  16 #include <time.h>
  17
  18 namespace __llvm_libc {
  19
  20 // TODO(michaelrj): Move this into time/linux with the other syscalls.
  21 LLVM_LIBC_FUNCTION(int, clock_gettime,
  22                    (clockid_t clockid, struct timespec *tp)) {
  23   long ret_val =
  24       __llvm_libc::syscall_impl(SYS_clock_gettime, static_cast<long>(clockid),
  25                                 reinterpret_cast<long>(tp));
  26   // A negative return value indicates an error with the magnitude of the
  27   // value being the error code.
  28   if (ret_val < 0) {
  29     libc_errno = -ret_val;
  30     return -1;
  31   }
  32
  33   return 0;
  34 }
  35
  36 } // namespace __llvm_libc