DosSleep requires one argument-the amount of time (in milliseconds) to suspend the thread. This value is rounded up to the nearest clock tick. If a time interval of 0 is specified, the thread gives up the remainder of the current time slice, enabling other ready threads of equal or higher priority to run; the calling thread will run again during its next scheduled time slice. If there is no other ready thread of equal or higher priority, DosSleep returns immediately; it does not yield to a thread of lower priority.
If there is a round-off error or if other threads in the system have higher priority, a thread might not resume execution immediately after the sleep interval.
The following DosSleep call suspends a thread for at least 5 seconds:
DosSleep(5000);Note that the specified time interval refers to execution time (accumulated scheduled time slices), not to elapsed real time. Elapsed real time will be longer and will vary, depending on the hardware and on the number and priorities of other threads running in the system. In addition, even though the calling thread is scheduled for execution as soon as the specified time interval has elapsed, its execution could be delayed if a higher priority thread is running or if a hardware interrupt occurs.
Because the above factors usually cause the sleep interval to be longer than requested (though generally within a few clock ticks), DosSleep should not be used as a substitute for a real-time clock.
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