SWI-Prolog -- sleep/1

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Availability:built-in

sleep(+Time)

Suspend execution Time seconds. Time is either a floating point number or an integer. Granularity is dependent on the system's timer granularity. A negative time causes the timer to return immediately. A zero time yields the CPU if this is supported on the target OS. On most non-realtime operating systems we can only ensure execution is suspended for at least Time seconds.

On Unix systems the sleep/1 predicate is realised ---in order of preference--- by nanosleep(), usleep(), select() if the time is below 1 minute, or sleep(). On Windows systems Sleep() is used.