Writing a Reply Filter Function
If your application calls AESend and chooses to yield the processor to other processes while waiting for a reply, you can provide an idle function to process
update, null, operating- system, and activate events and, additionally, you can
provide a reply filter function to process high-level events. The section
Your reply filter function can process any high-level events that it is willing
to handle while waiting for a reply Apple event. For example, your application
can choose to handle Apple events from other processes while waiting. Note,
however, that your application must maintain any necessary state information.
Your reply filter function must not accept any Apple events that can change the
state of your application and make it impossible to return to its previous state.
A reply filter function must use this syntax:
The parameter theEventRecord is the event record for a high-level event. The
next three parameters contain valid information only if the event is an Apple
event. The transactionID parameter is the transaction ID for the Apple event.
The returnID parameter is the return ID for the Apple event. The sender parameter contains the address of the application or process that sent the Apple
event.
Your reply filter function should return TRUE as the function result if you want to accept the Apple event; otherwise it should return FALSE. If your filter handler routine is called to process the Apple event.