libstdc++-v3/src/c++11/chrono.cc

   1 // chrono -*- C++ -*-
   2
   3 // Copyright (C) 2008-2018 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 #include <bits/c++config.h>
  26 #include <chrono>
  27
  28 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
  29
  30 // Conditional inclusion of sys/time.h for gettimeofday
  31 #if !defined(_GLIBCXX_USE_CLOCK_MONOTONIC) && \
  32     !defined(_GLIBCXX_USE_CLOCK_REALTIME) && \
  33      defined(_GLIBCXX_USE_GETTIMEOFDAY)
  34 #include <sys/time.h>
  35 #endif
  36
  37 #ifdef _GLIBCXX_USE_CLOCK_GETTIME_SYSCALL
  38 #include <unistd.h>
  39 #include <sys/syscall.h>
  40 #endif
  41
  42 namespace std _GLIBCXX_VISIBILITY(default)
  43 {
  44 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  45
  46   namespace chrono
  47   {
  48     // XXX GLIBCXX_ABI Deprecated
  49     inline namespace _V2 {
  50
  51     constexpr bool system_clock::is_steady;
  52
  53     system_clock::time_point
  54     system_clock::now() noexcept
  55     {
  56 #ifdef _GLIBCXX_USE_CLOCK_REALTIME
  57       timespec tp;
  58       // -EINVAL, -EFAULT
  59 #ifdef _GLIBCXX_USE_CLOCK_GETTIME_SYSCALL
  60       syscall(SYS_clock_gettime, CLOCK_REALTIME, &tp);
  61 #else
  62       clock_gettime(CLOCK_REALTIME, &tp);
  63 #endif
  64       return time_point(duration(chrono::seconds(tp.tv_sec)
  65                                  + chrono::nanoseconds(tp.tv_nsec)));
  66 #elif defined(_GLIBCXX_USE_GETTIMEOFDAY)
  67       timeval tv;
  68       // EINVAL, EFAULT
  69       gettimeofday(&tv, 0);
  70       return time_point(duration(chrono::seconds(tv.tv_sec)
  71                                  + chrono::microseconds(tv.tv_usec)));
  72 #else
  73       std::time_t __sec = std::time(0);
  74       return system_clock::from_time_t(__sec);
  75 #endif
  76     }
  77
  78
  79     constexpr bool steady_clock::is_steady;
  80
  81     steady_clock::time_point
  82     steady_clock::now() noexcept
  83     {
  84 #ifdef _GLIBCXX_USE_CLOCK_MONOTONIC
  85       timespec tp;
  86       // -EINVAL, -EFAULT
  87 #ifdef _GLIBCXX_USE_CLOCK_GETTIME_SYSCALL
  88       syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &tp);
  89 #else
  90       clock_gettime(CLOCK_MONOTONIC, &tp);
  91 #endif
  92       return time_point(duration(chrono::seconds(tp.tv_sec)
  93                                  + chrono::nanoseconds(tp.tv_nsec)));
  94 #else
  95       return time_point(system_clock::now().time_since_epoch());
  96 #endif
  97     }
  98
  99   } // end inline namespace _V2
 100   } // namespace chrono
 101
 102 _GLIBCXX_END_NAMESPACE_VERSION
 103 } // namespace std
 104
 105 #endif // _GLIBCXX_USE_C99_STDINT_TR1