Read Event Registration Endpoint

LabVIEW 2018 Help


Edition Date: March 2018
Part Number: 371361R-01
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Requires: Base Development System

Reads an event registration refnum for an Event Messenger channel.

You can drop this endpoint on the block diagram by right-clicking an Event Messenger channel terminal or wire and selecting Create»Channel Reader»Event Messenger»Read Event Registration.

Details  Example

channel is the channel wire that connects this endpoint to a writer endpoint.
event registration refnum returns the event registration refnum that this endpoint reads from the channel. You must wire this output to the dynamic event terminal of an Event structure to receive events from the channel.

Read Event Registration Details

Unlike the reader endpoints of other channel templates, this reader endpoint must be placed outside the While Loop and can execute only once.

Use one Event structure to handle events whenever possible. Use the Build Array or Bundle functions to combine multiple event registration refnums for a single Event structure.

Do not fork the event registration refnums to multiple Event structures. Doing so creates undefined behavior that may result in race conditions or deadlocks in your application.

Related Information

Write

Caveats and Recommendations when Using Events in LabVIEW

Example

Refer to the Channel - Event Messenger.lvproj in the labview\examples\Channels\Event Messenger directory for an example of using the Read Event Registration endpoint.

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