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ENVIBroadcastChannel::Subscribe

ENVIBroadcastChannel::Subscribe

The Subscribe method allows an object that implements ENVIMessageHandler to subscribe to the broadcast channel. Once subscribed, messages provided to the ENVIBroadcastChannel::Broadcast method are sent to the subscriber using the OnMessage method.

Syntax


ENVIBroadcastChannel.Subscribe, Subscriber [, ERROR=variable]

Arguments


Subscriber

An object that implements ENVIMessageHandler.

Keywords


ERROR

Set this keyword to a named variable that will contain any error message issued during execution of this routine. If no error occurs, the ERROR variable will be set to a null string (''). If an error occurs and the routine is a function, then the function result will be undefined.

When this keyword is not set and an error occurs, ENVI returns to the caller and execution halts. In this case, the error message is contained within !ERROR_STATE and can be caught using IDL's CATCH routine. See IDL Help for more information on !ERROR_STATE and CATCH.

See Manage Errors for more information on error handling in ENVI programming.

Version History


ENVI 5.3

Introduced

API Version


3.3

See Also


ENVIBroadcastChannel, ENVIBroadcastChannel::Broadcast, ENVIBroadcastChannel::Unsubscribe



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