The AS/400 has a built in debugging tool, though very powerful, it is not completely intuitive. Sometimes you may find yourself in need of a procedure that can help you locate program errors that you cannot visually find by looking at your program. RPG-ILE's program debugger can be very useful in these situations. It allows you to trace a program as it is executing, stepping through a program a statement at a time, or stopping at "breakpoints" that you designate so you can see the values of fields at that point of execution. Follow the steps below to start the "debugging" mode for your programs.
First, you must compile the program in an appropriate mode. Do this from PDM by keying a 14 next the program source and hitting F4.
Your screen should look like this:
Create Bound RPG Program (CRTBNDRPG)
Type choices, press Enter.
Program . . . . . . . . . . . . > LXR001 Name, *CTLSPEC
Library . . . . . . . . . . . > T40 Name, *CURLIB
Source file . . . . . . . . . . > QRPGLESRC Name, QRPGLESRC
Library . . . . . . . . . . . > T40 Name, *LIBL, *CURLIB
Source member . . . . . . . . . > LXR001 Name, *PGM
Generation severity level . . . 10 0-20
Text 'description' . . . . . . . *SRCMBRTXT
Default activation group . . . . *YES *YES, *NO
Now, hit F10 to get more options. Key in *LIST as the value for "Debugging View".
The screen should look like:
Create Bound RPG Program (CRTBNDRPG)
Type choices, press Enter.
Program . . . . . . . . . . . . > LXR001 Name, *CTLSPEC
Library . . . . . . . . . . . > T40 Name, *CURLIB
Source file . . . . . . . . . . > QRPGLESRC Name, QRPGLESRC
Library . . . . . . . . . . . > T40 Name, *LIBL, *CURLIB
Source member . . . . . . . . . > LXR001 Name, *PGM
Generation severity level . . . 10 0-20
Text 'description' . . . . . . . *SRCMBRTXT
Default activation group . . . . *YES *YES, *NO
Additional Parameters
Compiler options . . . . . . . . *XREF, *NOXREF, *GEN...
+ for more values
Debugging views . . . . . . . . *LIST *STMT, *SOURCE, *LIST...
Output . . . . . . . . . . . . . *PRINT *PRINT, *NONE
Now ENTER to compile your program. If this program calls other programs, you may want to
compile them in debug mode also.
Now it gets a little tricky. Start the debugging mode with the "Start Debug" for the program you want to debug. In this case, the program is LXR001 so the command to use is STRDBG LXR001. Key in STRDBG LXR001 and hit F14:
Start Debug (STRDBG)
Type choices, press Enter.
Program . . . . . . . . . . . . > LXR001 Name, *NONE
Library . . . . . . . . . . . *LIBL Name, *LIBL, *CURLIB
+ for more values
*LIBL
Default program . . . . . . . . *PGM Name, *PGM, *NONE
Maximum trace statements . . . . 200 Number
Trace full . . . . . . . . . . . *STOPTRC *STOPTRC, *WRAP
Update production files . . . . *NO *NO, *YES
OPM source level debug . . . . . *NO *NO, *YES
Service program . . . . . . . . *NONE Name, *NONE
Library . . . . . . . . . . . Name, *LIBL, *CURLIB
+ for more values
If your program updates or writes data to a file in a library that is defined as *PROD, you
must change the "Update production files" option to *YES. Then, hit ENTER.
The debugger now displays the source code of the program. You MUST define a breakpoint where the debugger will actually start debugging. The easiest thing to do is to page down to the first executable statement of the program. Put the cursor on that line of source code and hit F6 to define that line as a breakpoint.
Now, hit F3 and you will return to the PDM menu.
Your session is now in "debug" mode. It will stay in "debug" mode until you end debug mode with the command ENDDBG.
Finally, it is time to start running your program. Call the program from the command line. In this case: CALL LXR001
The program will start running. The debug feature will display a listing of the program. The display is showing that the breakpoint is about to execute. You can scroll up or down, position the cursor on any field and hit F11. The debugger will display the value of the field.
Now hit F10 repeatedly to step through the source code. The line of code that is about to execute will be highlighted.
Note that the debugger has the annoying habit of stepping through every field in each file that is read or updated. To prevent this, add a "header" record as the first line of code in the program. "Header" records are not required and not usually used. Use an "H" as the record type with a value of "option(*nodebugio). That is, add this line to the beginning of your program:
H OPTION(*NODEBUGIO)
When you are finished debuggin, key ENDDBG to turn off the debugger.
To summarize:
1) Add this line to the beginning of your program: H OPTION(*NODEBUGIO)
2) Compile the program with Debug View set to *LIST
3) Start the debugger with the command: STRDBG pgmname (Update Production files *YES)
4) Put cursor on the first line that you want to see and hit F6. Exit with F3.
5) Call your program: CALL pgmname
6) Use F10 to step through the program. Use F11 to see values.
7) If you wish, set additional breakpoints and use F12 to run until the next breakpoint.