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Obtain Notifier Function

LabVIEW 2013 Help

Edition Date: June 2013

Part Number: 371361K-01

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Owning Palette: Notifier Operations Functions

Requires: Base Development System

Returns a reference to a notifier.

Use this reference when calling other Notifier Operations functions.

Details  

name contains the name of the notifier that you want to obtain or create. The default is an empty string to create an unnamed notifier.
element data type is the type of data that you want the notifier to contain. You can wire any data type to this input.
create if not found? specifies whether you want to create a new notifier if one with the same name as name does not exist. If TRUE (default), the function creates a notifier if one with the same name does not exist.
error in describes error conditions that occur before this node runs. This input provides standard error in functionality.
notifier out is a reference to the existing named notifier or the new notifier created by this function.
created new? is TRUE if the function created a new notifier.
error out contains error information. This output provides standard error out functionality.

Obtain Notifier Details

Use named notifiers to pass data between two sections of a block diagram or between two VIs. If you do not wire name, the function creates a new, unnamed notifier reference. If you wire name, the function first searches for an existing notifier with the same name and returns a new reference to the existing notifier. If a notifier with the same name does not already exist and create if not found? is TRUE, the function creates a new, named notifier reference.

If you use the Obtain Notifier function to return a reference to a named notifier inside a loop, LabVIEW creates a new reference to the named notifier each time the loop iterates. If you use Obtain Notifier in a tight loop, LabVIEW slowly increases how much memory it uses because each new reference uses an additional four bytes. These bytes are released automatically when the VI stops running. However, in a long-running application it may appear as if LabVIEW is leaking memory since the memory usage keeps increasing. To prevent this unintended memory allocation, use the Release Notifier function in the loop to release the notifier reference for each iteration.

This function might return error codes 1, 2, 1094, 1100, or 1492.

Note  If you obtain a notifier reference in one application instance, you cannot use that notifier reference in another application instance. If you attempt to use a notifier reference in another application instance, LabVIEW returns error 1492.

 

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