Guardian Procedure Calls Reference Manual

timeout
input
INT(64)
specifies the time, in microseconds, to wait for the user event. Valid timeout ranges:
Call waits indefinitely until one of the events in waitMask occurs. The call never returns if none of the
user events occur.
< 0
Process will wait for specified duration; see Considerations.> 0
Call returns immediately with a valid event if already occurred or with 1.0
Returned Value
INT(32)
A bit mask containing a single bit indicating the result of the wait. It is the bit for the highest-priority
event in the waitMask that has occurred, or 1 if no event occurred in the allotted time.
Considerations
• USEREVENT_WAIT_ must be called by if the application is using user events, but not the
AWAITIO[X|XL], FILE_AWAITIO64_, or FILE_COMPLETE[L]_ procedures. Applications intending
to wait for user events using the AWAITIO[X|XL], FILE_AWAITIO64_, or FILE_COMPLETE[L]_
procedures, must use the USEREVENTFILE_REGISTER_ and USEREVENT_SET_ procedures
instead.
• Timeout considerations: If the wait times out, the process will awaken after at least timeout
microseconds. The actual delay is somewhat longer than the specified value, because:
◦ The specified timeout is rounded up to the resolution of the operating system interval
timing mechanism, which is approximately 2 milliseconds.
◦ Once the interval timer has elapsed, there is variable latency to process the timer interrupt
and schedule the process by priority, and then the process must read the message.
• For a general discussion about user events, see USEREVENT... Procedures (page 1464).
1472 Guardian Procedure Calls (T-V)