Using NULL Values or Pointers in LabVIEW

Updated Jan 13, 2020

Reported In

Software

  • LabVIEW

Issue Details

I want to call a .NET DLL that requires that a NULL value as an input. Is there a way that I can create a NULL value in LabVIEW?

Solution

There is no way to explicitly create a NULL value in LabVIEW that you can pass into a DLL. Some workarounds for this are:
  1. Within LabVIEW, configure the input parameter that you want to pass a NULL value to as a numeric passed by value. Pass a value of 0 into this input on the block diagram. Many, but not all DLLs will treat this as a NULL value.
  2. Create a wrapper DLL to handle NULL pointers/values outside of LabVIEW.

Additional Information

LabVIEW is a strongly typed language, meaning that all data must have a type defined for it before runtime. As a NULL value has no data type (Void), it can therefore not be used in the LabVIEW environment. 

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