libc/src/time/linux/clockGetTimeImpl.h

   1 //===- Linux implementation of the POSIX clock_gettime function -*- 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_TIME_LINUX_CLOCKGETTIMEIMPL_H
  10 #define LLVM_LIBC_SRC_TIME_LINUX_CLOCKGETTIMEIMPL_H
  11
  12 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
  13 #include "src/__support/common.h"
  14 #include "src/__support/error_or.h"
  15 #include "src/errno/libc_errno.h"
  16
  17 #include <stdint.h>      // For int64_t.
  18 #include <sys/syscall.h> // For syscall numbers.
  19 #include <time.h>
  20
  21 namespace LIBC_NAMESPACE {
  22 namespace internal {
  23
  24 LIBC_INLINE ErrorOr<int> clock_gettimeimpl(clockid_t clockid,
  25                                            struct timespec *ts) {
  26 #if SYS_clock_gettime
  27   int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_gettime,
  28                                               static_cast<long>(clockid),
  29                                               reinterpret_cast<long>(ts));
  30 #elif defined(SYS_clock_gettime64)
  31   static_assert(
  32       sizeof(time_t) == sizeof(int64_t),
  33       "SYS_clock_gettime64 requires struct timespec with 64-bit members.");
  34   int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_gettime64,
  35                                               static_cast<long>(clockid),
  36                                               reinterpret_cast<long>(ts));
  37 #else
  38 #error "SYS_clock_gettime and SYS_clock_gettime64 syscalls not available."
  39 #endif
  40   if (ret < 0)
  41     return Error(-ret);
  42   return ret;
  43 }
  44
  45 } // namespace internal
  46 } // namespace LIBC_NAMESPACE
  47
  48 #endif // LLVM_LIBC_SRC_TIME_LINUX_CLOCKGETTIMEIMPL_H