Data Types
You must specify a data type for each parameter in each instrument driver function. All data types the instrument driver uses must be intrinsic C data types or data types that you define in the .h file and list in the .fp file. Specify the data type of a parameter when you create its corresponding control on a function panel. This data type also must be consistent with the function prototypes in the instrument driver header file.
LabWindows/CVI uses the data type information to implement the variable declaration and run-time checking capabilities when users operate function panels. When you declare a variable from a function panel, LabWindows/CVI presents options based on the data type you specify for the function panel control. When you run a function from a function panel, LabWindows/CVI verifies that the data type of the value you enter in the control matches the prototype of the function.
Data types are divided into three classes: predefined data types, user-defined data types, and VISA data types.