Creating a SubVI From Code Turns Local Variables into Property Nodes

Updated Jun 26, 2018

Reported In

Software

  • LabVIEW

Issue Details

When I select some code and create a subVI from the selected code, the subVI gains a terminal that points to a reference if I have a local variable selected. Inside the subVI, the local variable changes into a property node. Why does it do this?

Solution

Local variables are tied to controls and indicators that are inside of their VI. When creating a subVI containing a local variable LabVIEW creates a reference and property node to properly maintain the reference to the control or indicator. Because of this they need property nodes with refunms so that their references can be passed from outside of the subVI. This is why any local variable will be changed to a Property Node as a subVI would need a reference passed to it to have the same functionality as a top level program with a Local Variable.

Additional Information

Here is a example of a VI undergoing this process starting with the VI before it is turned into a subVI:

After selecting all then clicking Edit»Create SubVI we generate the following code.
Here is the contents of the SubVI

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