Error -2147221480 When Trying to Build a DLL From a VI Using LabVIEW

Updated Nov 26, 2020

Reported In


  • LabVIEW

Operating System

  • Windows

Programming Language

  • C

Issue Details

  • My VI runs fine, but when I try to do the build to a DLL, I'm getting multiple C syntax error messages like the following:
"An error occurred compiling the DLL because a function or parameter name is illegal. Please verify that the function and/or parameter names are legal C identifiers and do not conflict with LabVIEW headers.
Additional Information: SharedLib.c - 9 errors"

  • When I try to build a DLL with LabVIEW the software throws me the (Error-2147221480) and it shows some errors regarding the syntax of my code.


In most of the cases, this error is related to a conflict with the name of the variables or the components inside the VI with the 'C' programming language.
In order to solve this issue:
  • Please verify that you are not passing string data with the incorrect method. (See Create LabVIEW DLL to Pass Strings)
  • Review the syntax error that the error message is stating and verify if in some of your VIs there is a component called that way, if so, please re-name all the components and try building your DLL again.
  • If the issue persists, contact NI support.