M520 Cross Program Communication in z/OS

Course Code: M-520
Recommended Duration: 3 Days

Benefits

This course helps experienced programmers find the most productive ways to combine functions and modules written in different programming languages (or the same language). The student will gain new insights on how each language builds argument lists and accesses parameters. This can result in code that is smaller, faster, and more robust.

Audience

Experienced programmers who need to create or maintain applications that include components written in various languages, or who need to use some of the advanced subroutine features of a particular language or the program binder.

Prerequisites

At the very least, the student entering this course should have a strong programming background in at least one of: COBOL, PL/I, C, or Assembler.

Related IBM Materials

This course is drawn from these and other IBM manuals; access to these publications in the classroom is desirable but not required:

SA22-7832 - z/Architecture Principles of Ops.
SC26-4940 - HLASM Language Reference
SA22-7606 - Assembler Services Reference, I
SA22-7607 - Assembler Services Reference, II
SC27-1408 - Enterprise COBOL Language Reference
SC27-1412 - Enterprise COBOL Programming Gde.
SC27-1460 - Enterprise PL/I Language Reference
SC27-1457 - Enterprise PL/I Programming Guide
SC09-4815 - XL C/C++ Language Reference
SC09-4765 - XL C/C++ Programming Guide
SC09-4767 - XL C/C++ User's Guide
SA22-7821 - XL C/C++ Run-Time Library Ref.
SA22-7643 - MVS Program Mgmt. User's Guide
SA22-7644 - MVS Program Mgmt. Advanced Facilities

Major Topics Include

Defining data (items, structures, arrays) in four languages
Converting between null-terminated strings and traditional strings in four languages
Working with halfword-prefixed strings in four languages
Accessing the JCL PARM and setting the JCL return code in four languages and using LE services
Static calls and function references
Passing arguments, including: passing by reference and by value; passing a variable number of arguments; setting the end-of-list flag; omitting arguments; providing a return value area
Receiving parameters, including: receiving by reference and by value; handling a variable number of parameters; testing for the end-of-list flag; testing for omitted parameters; providing a return value; how subroutines can behave like functions, and vice-versa
Object code formats: OBJ, XOBJ, GOFF
The program binder
Executables: load modules, program objects
Alternate entry points
Shared external data
Multi-tasking issues
Dynamic calls and function references
Addressing concerns and AMODE / RMODE issues
Module attributes (reusable, reenterable, refreshable)

Exercises

There are nine hands-on exercises.

Note

The exercises are designed to be solved using any (or all) of COBOL, PL/I, Assembler, or C; there are starter programs supplied in all four languages, along with necessary JCL.

Course Description

Cross Program Communication in z/OS