This example illustrates how to pass all sorts of data types from C code to LabVIEW through the Call Library Function in LabVIEW(which uses DLLs). The C code shows how to dynamically create data and pass it to LabVIEW using the LabVIEW memory manager functions. The C code displays how to modify data passed from LabVIEW and change the contents of that data. The C code also shows how LabVIEW can pass and accept standard C data types like double* for arrays or char* for strings, in addition to passing the native LabVIEW structures to C code and how to handle them.
Example code from the Example Code Exchange in the NI Community is licensed with the MIT license.