libc/src/time/linux/gettimeofday.cpp

   1 //===-- Implementation of gettimeofday 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/gettimeofday.h"
  10 #include "hdr/time_macros.h"
  11 #include "hdr/types/suseconds_t.h"
  12 #include "src/__support/common.h"
  13 #include "src/__support/macros/config.h"
  14 #include "src/__support/time/clock_gettime.h"
  15 #include "src/__support/time/units.h"
  16 #include "src/errno/libc_errno.h"
  17
  18 namespace LIBC_NAMESPACE_DECL {
  19
  20 // TODO(michaelrj): Move this into time/linux with the other syscalls.
  21 LLVM_LIBC_FUNCTION(int, gettimeofday,
  22                    (struct timeval * tv, [[maybe_unused]] void *unused)) {
  23   using namespace time_units;
  24   if (tv == nullptr)
  25     return 0;
  26
  27   struct timespec ts;
  28   auto result = internal::clock_gettime(CLOCK_REALTIME, &ts);
  29
  30   // A negative return value indicates an error with the magnitude of the
  31   // value being the error code.
  32   if (!result.has_value()) {
  33     libc_errno = result.error();
  34     return -1;
  35   }
  36
  37   tv->tv_sec = ts.tv_sec;
  38   tv->tv_usec = static_cast<suseconds_t>(ts.tv_nsec / 1_us_ns);
  39   return 0;
  40 }
  41
  42 } // namespace LIBC_NAMESPACE_DECL