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Returns a reference to a queue.

Use this reference when calling other Queue Operations functions.

Details  Example

	max queue size is the maximum number of elements you want the queue to hold. The default is –1, specifying that the queue can hold an unlimited number of elements. If a queue reaches max queue size, the Enqueue Element or Enqueue Element at Opposite End functions wait until the Dequeue Element or Flush Queue functions remove elements from the queue. If a queue with the same name exists, LabVIEW ignores this input and uses the size from the existing queue. Note  max queue size only limits the number of elements in the queue. It does not preallocate memory. Enqueue the maximum number of elements and flush the queue to preallocate the queue. The queue reserves more memory as its size increases and releases that memory only when you destroy the queue.
	name contains the name of the queue that you want to obtain or create. The default is an empty string to create an unnamed queue.
	element data type is the type of data that you want the queue to contain. You can wire any data type to this input.
	create if not found? specifies whether you want to create a new queue if one with the same name as name does not exist. If TRUE (default), the function creates a queue if one with the same name does not exist.
	error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	queue out is a reference to the existing named queue or the new queue created by this function.
	created new? is TRUE if the function created a new queue.
	error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

Obtain Queue Details

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

If you use the Obtain Queue function to return a reference to a named queue inside a loop, LabVIEW creates a new reference to the named queue each time the loop iterates. If you use Obtain Queue 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 Queue function in the loop to release the queue reference for each iteration.

This function might return error codes 1, 2, 1094, 1100, or 1491.

Note  You cannot use queues or named queues to communicate across application instances. If you attempt to communicate with a named queue in another application instance, LabVIEW does not return an error but you might not receive the expected results. If you obtain a queue reference in one application instance, you cannot use that queue reference in another application instance. If you attempt to use a queue reference in another application instance, LabVIEW returns error 1491.

Example

Refer to the Queue Basics VI in the labview\examples\general\queue.llb for an example of using the Obtain Queue function.