SleepEx

The SleepEx function causes the current thread to enter a wait state until one of the following occurs:- An I/O completion callback function is called- An asynchronous procedure call (APC) is queued to the thread.- The time-out interval elapses

- dwMilliseconds
Specifies the time, in milliseconds, that the delay is to occur. A value of zero causes the function to return immediately. A value of INFINITE causes an infinite delay.

- bAlertable
Specifies whether the function may terminate early due to an I/O completion callback function or an APC. If bAlertable is FALSE, the function does not return until the time-out period has elapsed. If an I/O completion callback occurs, the function does not return and the I/O completion function is not executed. If an APC is queued to the thread, the function does not return and the APC function is not executed.
If bAlertable is TRUE and the thread that called this function is the same thread that called the extended I/O function (ReadFileEx or WriteFileEx), the function returns when either the time-out period has elapsed or when an I/O completion callback function occurs. If an I/O completion callback occurs, the I/O completion function is called. If an APC is queued to the thread (QueueUserAPC), the function returns when either the timer-out period has elapsed or when the APC function is called.

The return value is zero if the specified time interval expired.

The return value is WAIT_IO_COMPLETION if the function returned due to one or more I/O completion callback functions. This can happen only if bAlertable is TRUE, and if the thread that called the SleepEx function is the same thread that called the extended I/O function.