> Question: Which intrinsic can I use to wait until a request is ready to
be processed?

Not sure what this means. Probably the most common asynchronous processing
is to use IPCRECV in NOWAIT mode, so you don't hang if there's no incoming
traffic. Use IODONTWAIT to see if the request has been satisfied, and IOWAIT
to complete the receive operation. If this is completely OTL, please provide
more details on the requirement.

Steve