Psychtoolbox>GetSecs.{mex*} subfunction

[GetSecsTime, WallTime, syncErrorSecs, MonotonicTime] = GetSecs(‘AllClocks’ [, maxError=0.000020]);

Return current time in seconds according to all supported clocks.

‘GetSecsTime’ is the usual GetSecs() clock, as returned by GetSecs(), in the
timebase used by all other Psychtoolbox functions, e.g., Screen(‘Flip’) or
PsychPortAudio timestamps.

‘WallTime’ is real-world system time in an operating system specific timebase.
This clock is expected to be subject to time adjustments by the system
administrator or by automated mechanisms like NTP time adjustments. Useful for
synchronizing clocks across multiple machines on a local network, as it is
possible for this clock to get automatically corrected for drift.
On Linux and OSX, the timebase is gettimeofday(), seconds since 1. January 1970
00:00:00 UTC, with about 1 microsecond precision.
On MS-Windows the timebase is also UTC time, with about 1 millisecond
granularity, measuring elapsed seconds since 1. January 1601 00:00:00 UTC via
the GetSystemTimeAsFileTime() function.

‘syncErrorSecs’ How tightly together did the returned clock times get queried? A
measure of confidence as to how much all returned times actually denote the same
point in physical time.

‘MonotonicTime’ is system monotonic timebase, not subject to administrator or
NTP time adjustments, with a zero point at operating system boot time. Identical
to ‘GetSecsTime’ on Windows and macOS, identical to Posix clock CLOCK_MONOTONIC
on GNU/Linux.

The input argument ‘maxError’ allows to set an allowable upper bound to
‘syncErrorSecs’. The default value is 20 microseconds. The function will try up
to 10 times to get a result no worse than ‘maxError’, and output a warning if it
doesn’t manage, e.g., due to some severely overloaded or deficient system.

###See also: