Debugging Applications Without Source Code (Code Debug CICS PL/I)

As discussed in Preparing a Program for Execution (Code Debug CICS PL/I), the typical Code Debug CICS test begins by processing the application program with the BMC language processor. This process creates an online source listing that allows you to interactively step through your source code as it executes. However, if this source listing is not available, you can still test your programs with Code Debug CICS using a form of testing called sourceless debugging.

This section demonstrates two methods for using sourceless debugging when testing your applications: PSEUDOSOURCE and Line Mode. You can still use Code Debug CICS to set breakpoints, intercept abends, step through instructions, modify data, and generally test your program.

The PSEUDOSOURCE command allows you to map a program or CSECT to create an Assembler pseudo-listing. This pseudo-listing displays the underlying instructions in memory as if it was an Assembler program processed by the BMC Assembler Language Processor. While you need some experience in debugging assembler language, the capability to debug a program or CSECT provides you with a much richer set of commands. It is important to understand that debugging a PL/I program using PSEUDOSOURCE is not a trivial undertaking. Having a compiler listing can make the task easier, but is not a requirement.

Line Mode debugging, although somewhat more complicated than using a pseudo-listing produced by the PSEUDOSOURCE command, still provides a set of commands that allows sourceless debugging of a PL/I program. Since you do not have a pseudo-listing available, you are restricted to using offsets and working with a single assembler instruction. In Line Mode, having a copy of the compiler listing is of tremendous help. You also need to decipher assembler instructions by looking at the hexadecimal display of storage that can be obtained from the 2.2 screen.

The following scenarios are based on the application transaction XPLE. This is the sample payroll transaction shipped with Code Debug CICS that executes the PL/I program CWDEMPE. Since sourceless debugging mandates that no source listing exists for the program in question, you may wish to use a program of your own.