The operating system includes functions that let a programmer observe operations performed as a program runs.
Testing functions can be used to locate operations that are not performing as intended. These functions can be used in either batch or interactive jobs from a workstation. In either case, the program being observed must be in the testing environment, called debug mode.
The testing functions narrow the search for errors that are difficult to find in the procedure's source statements. Often, an error is apparent only because the output produced is not what is expected. To find those errors, you need to be able to stop the program at a given point (called a breakpoint) and examine variable information in the program to see if it is correct. You might want to make changes to those variables before letting the program continue running.
You do not need to know machine language instructions, nor is there a need to include special instructions in the program to use the testing functions. The i5/OS™ testing functions let you:
This section contains expanded descriptions of the program variable, basing pointer, subscript, and qualified-name parameter values. These values can be specified on the Add Breakpoint (ADDBKP), Add Trace (ADDTRC), Change High-Level Language Pointer (CHGHLLPTR), Change Program Variable (CHGPGMVAR), and Display Program Variable (DSPPGMVAR) commands.
See the appropriate ILE guide for debugging information with other ILE languages.