Configure Call Library Function Node for Function Returning Pointer

Updated Jan 14, 2019

Reported In


  • LabVIEW 2017 Professional
  • LabVIEW 2016 Professional
  • LabVIEW 2015 SP1 Professional

Issue Details

In my LabVIEW VI I would like to call a function from a C language DLL using the Call Library Function Node. The header file shows that function returns a pointer of "unsigned char" type. Such data type is not available on when I am configuring the data type of the return parameter on the Parameters tab of the Call Library Function configuration dialog. What data type should I configure in this case?


In this case use the following settings:
  1. Double click the Call Library Function Node to display the Call Library Function configuration dialog.
  2. On the Parameters tab click return type in the parameter list.
  3. Set Type to Numeric.
  4. Set Data type to Signed Pointer-sized Integer.

Additional Information

For more information about passing and receiving pointers between C/C++ DLLs and LabVIEW please refer to this page.
If you need to access data that is referenced by the pointer directly in your LabVIEW VI (dereferencing), please refer to this page.


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