Linking

[carolly]

I am a little confused about linking sub programs. My books state that the main program will call the subprogram from a library. It must have the same details in Working Storage as the linkage section in the subprogram to be called, but how does the subprogram become part of a library?

 

[RonaldB]

Carolly,

there are basically three ways of using a sub program:

1. including the code in the same source as the main program; in this way, they are compiled together in one object.
2. statically linking the object together with that of the main program into one executable; the location of the sub-program object has to be known at compile-time.
3. dynamically calling the sub-program.

Only in the last way there is actually a seperate object needed at run-time. The environment you are working in determines where that object should be, and how it is found.
Using JCL, for instance, the libraries / directories where called objects can be found are listed in the job.

Hope this helps; if not, please get back with us.

Regards,
Ronald.

 

[StephenJSpiro]

When the subprogram (not a "nested" program) is compiled, it is put into a library, just as is a main program. In fact, in many shops, it is the same library. If it is called dynamically in an IBM mainframe environment, you will need a STEPLIB card pointing to that library.

Stephen J Spiro
Member, J4 COBOL Standards Committee
check it out at

http://people.ne.mediaone.net/doncobol/

stephenjspiro at hotmail.com