Ichthyostega
4e9d54e6f9
Obviously the better choice and a perfect fit for our requirements; while the system-clock may jump and even move backwards on time service adjustments, the steady clock just counts the ticks since last boot. In libStdC++ both are implemented as int64_t and use nanoseconds resolution
64 lines
1.9 KiB
C++
64 lines
1.9 KiB
C++
/*
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RealClock - convenience front-end to access the system clock
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Copyright (C) Lumiera.org
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2012, Hermann Vosseler <Ichthyostega@web.de>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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* *****************************************************/
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/** @file real-clock.cpp
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** Implementation of simplified access to current system time.
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** Actually, a _steady clock_ is employed, with an unspecified base time,
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** typically starting anew at each system boot. The micro-tick value will
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** increase monotonously, without gaps at NTP corrections, but also without
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** any relation to an external world time.
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*/
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#include "vault/real-clock.hpp"
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#include <chrono>
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using lib::time::FSecs;
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using std::chrono::steady_clock;
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using std::chrono::microseconds;
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using std::chrono::floor;
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namespace vault {
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/** events during the last ms are considered "recent" for the purpose of testing */
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const Offset RealClock::CONSIDERED_RECENT{FSecs {1,1000}};
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TimeValue
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RealClock::_readSystemTime()
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{
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auto now = steady_clock::now();
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auto microTicks = floor<microseconds> (now.time_since_epoch())
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.count();
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ENSURE (microTicks == _raw(TimeValue{microTicks}));
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return TimeValue::buildRaw_(microTicks); // bypassing the limit check
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}
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} // namespace vault
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