Event types

Event types are categorized as follows:

• Timer events

  These can be either one-time timers or interval timers.

• Sink events (sockets, file descriptors, and message queues)

  On AIX, this includes file descriptors for input/output files, sockets, pipes, and message queues. On OS/2 and Windows, only TCP/IP sockets are supported.

  Note:On OS/2 and Windows, the Sockets classes for NetBIOS (NBSockets) and Novell IPX/SPX (IPXSockets) are primarily intended for use by DSOM and the Replication Framework, not for general application programming. (The Replication Framework is available as part of the full-capability SOMobjects Developer Toolkit.)

• Client events (any event that the application wants to queue with EMan)

  These events are defined, created, processed, and destroyed by the application. EMan simply acts as a place to queue these events for processing. EMan dispatches these client events whenever it sees them. Typically, this happens immediately after the event is queued.

• Work procedure events (procedures that can be called when there is no other event)

  These are typically background procedures that the application intends to execute when there are spare processor cycles. When there are no other events to process, EMan calls all registered work procedures. A work procedure event is called only after all other higher priority events have been called. A work procedure event is not called if there are no other events to be processed.

The Event Management Framework is extendible (that is, other event types can be added to it) through subclassing. The event types currently supported by EMan are at a sufficiently low level so as to enable building other higher level application events on top of them. For example, you can build an X-event handler by simply registering the file descriptor for the X connection with EMan and getting notified when any X-event occurs.