Progress
Programming
Handbook
Feature Summary
Progress named events allow the following:
- Any procedure or widget within the current Progress session can generate a named event by using the PUBLISH statement.
- Any procedure within the current Progress session can subscribe to a named event by using the SUBSCRIBE statement. Each subscriber contains an internal procedure that Progress runs when the named event occurs. By default, the name of this internal procedure (the local internal procedure) is the name of the event. The subscriber can specify a different name by using the SUBSCRIBE statement’s RUN–PROCEDURE option.
NOTE: A widget can publish, but not subscribe to, a named event.
- A potential subscriber can find out about named events of interest by using the PUBLISHED–EVENTS attribute.
- Subscribers can cancel subscriptions by using the UNSUBSCRIBE statement.
- Named events can pass parameters and thus have signatures (the number of parameters, and the data type and mode (INPUT, OUTPUT, etc.) of each).
NOTE: Progress supports named events within single Progress sessions only. In other words, a procedure in one session cannot subscribe to a named event created in another session. You can, however, build a Progress procedure that functions as a message broker, routing named events among procedures or widgets within a single Progress session.
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