Data Value Reference Read / Write Element Border Node

LabVIEW 2018 Help


Edition Date: March 2018
Part Number: 371361R-01
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Owning Palette: Structures

Requires: Base Development System

Accepts a data value reference or an external data value reference as an input, allows you to operate on the data within the In Place Element structure, and replaces that data in the original memory space.

You can enable read-only access to the data value reference by right-clicking the border node on the right of the structure and selecting Allow Parallel Read-only Access. When the border node on the right is unwired, LabVIEW allows multiple, concurrent read-only operations and does not modify the data value reference.

Right-click the border of an In Place Element structure and select Add Data Value Reference Read / Write Element from the shortcut menu to place this border node on the In Place Element structure. You cannot find these border nodes in the palette search or quick drop search.

Details  

data value reference is the reference that points to the data you want to access.
data value is the data the reference points to.
Note  LabVIEW cannot resize the data in an external data value reference. This node produces an error if the array in an external data value reference is a different size than the array you wire to the right side of the border node. If you wire an array with more elements than are in the reference array to the border node on the right, LabVIEW truncates the elements to fit in the reference array. If you wire an array with fewer elements to the border node on the right, LabVIEW adds default data to the reference array until it is filled.
data value reference is the reference that points to the new data.
error out contains error information. This output provides standard error out functionality.

Data Value Reference Read / Write Element Details

Use this border node to operate on the data in place.

If a data value reference points to a class object, you cannot replace that class object with a different LabVIEW class object inside the In Place Element structure. However, you can replace any other object with an object of the same type.

Note  This border node provides serialized access to the reference you wire to the structure. When part of a VI obtains access to the reference, LabVIEW blocks the rest of the VI or other VIs from simultaneous access. If you attempt to access a reference twice at the same time in the same structure, LabVIEW returns a run-time error. If you attempt to access the reference after you obtain access inside the In Place Element structure, the VI might hang. You can enable multiple, concurrent read-only operations that do not modify the data value reference by right-clicking the border node on the right of the structure and selecting Allow Parallel Read-only Access.

You can acquire the error output of the Data Value Reference Read / Write Element border node by wiring the error out terminal of the border node on either side of the structure. It is not necessary to wire the error out terminals of the border nodes on both sides of the structure because they have the same error output.

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