Micro Focus Visual COBOL 2.3 for Visual Studio 2015 > Programming > Hints and Tips > Performance Programming > Optimizing COBOL Syntax > Optimizing Parameter Handling

Optimizing Parameter Handling

When calling a subprogram, there are a number of ways to optimize the parameters being passed.

You can optimize the way parameters are handled as follows:

Put the parameters in the CALL statement in the same order as their descriptions in the called program's Linkage Section.
Ensure that any Linkage Section items that are not referenced in the Procedure Division header appear after those that are referenced.
Avoid making many references to linkage items. These include items that are defined in the Linkage Section, items set to CBL_ALLOC_MEM allocated memory, and items defined as EXTERNAL.

It is always slower to access Linkage Section items than Working-Storage Section items. If a Linkage Section item is used frequently, it is faster to move it into a Working-Storage Section when the program is entered and move it back to the Linkage Section, if necessary, before returning to the calling program. Instead of the Linkage Section item, the Working-Storage Section item should then be accessed throughout the program.

If a linkage parameter is optional, you can detect its presence using a statement such as:

IF address of linkage-item NOT = null

However, this statement works only if the NOPARAMCOUNTCHECK Compiler directive is specified, and its construct is considered poor programming practice.