When you call a module, you must pass the names of pre-defined parameter structures. These parameter structures are blocks of memory containing data used by both your driver program and the callable module.
Each parameter structure has an associated map. These maps describe the data stored in each byte in the parameter structure. Because these maps are specific, both the callable module and the driver program know where each piece of data is stored in the parameter structure. Therefore, instead of passing all of the data between the driver and the callable module, the only parameter passed between the two programs is the name of the parameter structure.
Note: Each function includes a parameter structure called
long lFixedString that
enables you to null-terminate input/output strings or treat input/output strings as
fixed buffers that are space-padded and not null-terminated. When defining this
parameter structure, a value of 0 causes the function to null-terminate character
strings so that trailing spaces are trimmed. The elements in the following parameter
structures include room for the null-termination byte, and this is shown as [+1] under
the Length heading in the parameter structure maps. Any value you enter other than 0
causes the function to treat character strings as fixed buffers, padding the remainder
of the line with blanks.