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Function core.time.TickDuration.currSystemTick

The current system tick. The number of ticks per second varies from system to system. currSystemTick uses a monotonic clock, so it's intended for precision timing by comparing relative time values, not for getting the current system time.

On Windows, QueryPerformanceCounter is used. On Mac OS X, mach_absolute_time is used, while on other Posix systems, clock_gettime is used. If mach_absolute_time or clock_gettime is unavailable, then Posix systems use gettimeofday (the decision is made when TickDuration is compiled), which unfortunately, is not monotonic, but if mach_absolute_time and clock_gettime aren't available, then gettimeofday is the the best that there is.

Warning: On some systems, the monotonic clock may stop counting when the computer goes to sleep or hibernates. So, the monotonic clock could be off if that occurs. This is known to happen on Mac OS X. It has not been tested whether it occurs on either Windows or on Linux.

Prototype

static TickDuration currSystemTick() nothrow @property @nogc @trusted;

Throws

TimeException if it fails to get the time.

Authors

Jonathan M Davis and Kato Shoichi

License

Boost License 1.0.

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