Understanding the return value and content of the functions

The returned value is a key component of functions.

ARCHLine.XP defines a private integer called callReturn and string called callResult for sharing data with other applications.

The int callReturn variable contains the function’s result and send back to the caller.
0 typically means success and negative value means failure.

The std::string callResult contains information about the result of the function.

Example:  

GET_DATA IFC ID num

Exports the geometry and parameters of the selected element to an IFC file.

The function returns the IFC file name as a string in the environment variable called "callResult".