Creates a subscription to an ABL named event.
SUBSCRIBE [ PROCEDURE subscriber-handle] [ TO ] event-name { IN publisher-handle | ANYWHERE } [ RUN-PROCEDURE local-internal-procedure ] [ NO-ERROR ] |
A procedure or handle representing the subscriber.
The PROCEDURE option lets one procedure create a subscription on behalf of another. For example, if you want procedure A to create a subscription on behalf of procedure B, set subscriber-handle to the procedure handle of B.
If the PROCEDURE option does not appear, the AVM creates a subscription on behalf of THIS-PROCEDURE, the procedure that contains the SUBSCRIBE statement.
A quoted string or a character expression representing the name of the event.
Subscribes to the named events published by publisher-handle.
If publisher-handle is not a valid procedure or widget handle at the time the SUBSCRIBE statement executes, the AVM reports a run-time error unless you specify the NO-ERROR option.
Subscribes to named events published within the ABL session, regardless of the publisher.
A quoted string or character expression representing the name of an internal procedure that resides within the subscribing program. The AVM runs local-internal-procedure when the named event occurs.
If the RUN-PROCEDURE option does not appear, when the named event occurs, the AVM runs an internal procedure with the same name as the named event.
When the named event occurs, the AVM RUNs each subscriber's local internal procedure, passing the parameters, if any, The order in which the AVM notifies subscribers is undefined. The AVM always performs this RUN with an implicit NO-ERROR, and logs errors to the ERROR-STATUS system handle.
Suppresses ABL errors or error messages that would otherwise occur and diverts them to the ERROR-STATUS system handle. If an error occurs, the action of the statement is not done and execution continues with the next statement. If the statement fails, any persistent side-effects of the statement are backed out. If the statement includes an expression that contains other executable elements, like methods, the work performed by these elements may or may not be done, depending on the order the AVM resolves the expression elements and the occurrence of the error.
For the SUSCRIBE statement with NO-ERROR, this option tells the AVM not to report a run-time error if publisher-handle or subscriber-handle is not a valid procedure handle, or if the AVM cannot evaluate an event-name expression.
To check for errors after a statement that uses the NO-ERROR option:
If the statement does not include the NO-ERROR option, you can use a CATCH end block to handle errors raised by the statement.
Some other important usage notes on the NO-ERROR option: