13. Program Segmentation
Program segmentation is the process of dividing a pro-
gram into small, manageable routines and modules. In a
segmented or modular program, each routine or module
usually performs only one logical function. You can, there-
fore, design and implement a modular program faster than a
nonsegmented program. Program modularity also simplifies
debugging and testing, as well as program maintenance and
transportability.
This chapter describes how to:
Subprograms processed by the BASIC compiler conform
to the OpenVMS Procedure Calling Standard. This stan-
dard prescribes how arguments are passed, how values are
returned, and how procedures receive and return control.
Because BASIC conforms to the OpenVMS Procedure Calling
Standard, a BASIC subprogram or main program can call
or be called by any procedure written in a language that
also conforms to this standard. For information about calling
non-BASIC procedures, see Chapter 20.