1 // chrono -*- C++ -*- 2 3 // Copyright (C) 2008-2020 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 // Conditional inclusion of sys/time.h for gettimeofday 29 #if !defined(_GLIBCXX_USE_CLOCK_MONOTONIC) && \ 30 !defined(_GLIBCXX_USE_CLOCK_REALTIME) && \ 31 defined(_GLIBCXX_USE_GETTIMEOFDAY) 32 #include <sys/time.h> 33 #endif 34 35 #ifdef _GLIBCXX_USE_CLOCK_GETTIME_SYSCALL 36 #include <unistd.h> 37 #include <sys/syscall.h> 38 #endif 39 40 namespace std _GLIBCXX_VISIBILITY(default) 41 { 42 _GLIBCXX_BEGIN_NAMESPACE_VERSION 43 44 namespace chrono 45 { 46 // XXX GLIBCXX_ABI Deprecated 47 inline namespace _V2 { 48 49 constexpr bool system_clock::is_steady; 50 51 system_clock::time_point now()52 system_clock::now() noexcept 53 { 54 #ifdef _GLIBCXX_USE_CLOCK_REALTIME 55 timespec tp; 56 // -EINVAL, -EFAULT 57 #ifdef _GLIBCXX_USE_CLOCK_GETTIME_SYSCALL 58 syscall(SYS_clock_gettime, CLOCK_REALTIME, &tp); 59 #else 60 clock_gettime(CLOCK_REALTIME, &tp); 61 #endif 62 return time_point(duration(chrono::seconds(tp.tv_sec) 63 + chrono::nanoseconds(tp.tv_nsec))); 64 #elif defined(_GLIBCXX_USE_GETTIMEOFDAY) 65 timeval tv; 66 // EINVAL, EFAULT 67 gettimeofday(&tv, 0); 68 return time_point(duration(chrono::seconds(tv.tv_sec) 69 + chrono::microseconds(tv.tv_usec))); 70 #else 71 std::time_t __sec = std::time(0); 72 return system_clock::from_time_t(__sec); 73 #endif 74 } 75 76 77 constexpr bool steady_clock::is_steady; 78 79 steady_clock::time_point now()80 steady_clock::now() noexcept 81 { 82 #ifdef _GLIBCXX_USE_CLOCK_MONOTONIC 83 timespec tp; 84 // -EINVAL, -EFAULT 85 #ifdef _GLIBCXX_USE_CLOCK_GETTIME_SYSCALL 86 syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &tp); 87 #else 88 clock_gettime(CLOCK_MONOTONIC, &tp); 89 #endif 90 return time_point(duration(chrono::seconds(tp.tv_sec) 91 + chrono::nanoseconds(tp.tv_nsec))); 92 #else 93 return time_point(system_clock::now().time_since_epoch()); 94 #endif 95 } 96 97 } // end inline namespace _V2 98 } // namespace chrono 99 100 _GLIBCXX_END_NAMESPACE_VERSION 101 } // namespace std 102