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Get Queue Status (G Dataflow)

Last Modified: November 4, 2020

Returns information about the current state of a queue, such as the number of elements currently in the queue.

Using this node in parallel code may result in race conditions. To avoid race conditions, use this node only for monitoring and not for controlling code.

Programming Patterns

Transferring Data Between Loops Using Queue Nodes



A reference to a queue.


return elements

A Boolean value that determines whether to return the elements in the queue.

True This node returns the elements in the queue.
False This node does not return the elements in the queue.

Default: False


error in

Error conditions that occur before this node runs. Unlike most nodes, this node runs normally even if an error occurs before this node runs.

Default: no error


max queue size

The maximum number of elements the queue can contain.

If max queue size is -1, the queue can contain an unlimited number of elements.


queue name

The name of the queue, if the queue is named.


queue out

Reference to the queue.


number pending remove

The number of Dequeue Element or Preview Queue Element nodes currently waiting to remove an element from the queue.


number pending insert

The number of Enqueue Element or Enqueue Element at Opposite End nodes currently waiting to insert an element in the queue.

If the maximum queue size is -1, this output returns 0.


error out

Error information.

The node produces this output 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.

number elements in queue

Current number of elements in the queue.



An array of all the elements currently in the queue.

If return elements? is set to False, this output returns an empty array.

The data type of the array elements changes to match the data type of the queue elements.

Verifying Valid Queue References

You can use Get Queue Status to verify that a queue reference is valid. If a queue reference is not valid, this node returns error code 1.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Supported in VIs that run in a web application

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