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Obtain Notifier (G Dataflow)

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Last Modified: August 7, 2018

Returns or creates a reference to a notifier.

Use the reference this node creates when calling other Notifier nodes.

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name

The name of the notifier that you want to obtain or create.

Default: unnamed

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element data type

The type of data that you want the notifier to contain.

You can wire any data type to this input.

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create if not found

A Boolean that determines whether to create a new notifier if one with the same name as name does not exist.

True The node creates a notifier if one with the same name as name does not exist.
False The node does not create a notifier if one with the same name as name does not exist.

Default: True

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error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error

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notifier out

A reference to the existing named notifier or the new notifier created by this node.

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created new?

A Boolean that indicates whether the node created a new notifier.

True The node created a new notifier.
False The node did not create a new notifier.
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error out

The node produces this output according to standard error behavior.

This node can return the following error codes.

1094 You tried to obtain an existing queue or notifier reference with the incorrect data type. You can get this error when you obtain a reference to the same queue or notifier but do not wire the same data type as the original specified data type. Unnamed queues and notifiers do not have this restriction, because each request to obtain an unnamed queue or notifier creates a new reference.
1100 You tried to obtain a queue or notifier that does not exist, so no reference could be returned. You can use the Obtain Queue or Obtain Notifier nodes to look up a queue or notifier by name. This error occurs if create if not found is set to False, and a queue or notifier with the name you specify was not found.
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Note  

This is not a comprehensive list of errors this node can return.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Preventing Unintended Memory Allocation Inside a Loop

When called inside a loop, the Obtain Notifier node creates a new reference to the notifier each time the loop iterates and memory usage increases because each new reference is an additional four bytes. These bytes are automatically released when the VI stops running. However, in a long-running application, there may appear to be leaking memory as memory usage keeps increasing. To prevent unintended memory allocation, use the Release Notifier node in the loop to release the notifier reference from memory for each iteration or use Obtain Notifier once before the loop begins executing.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application

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