You can use the Add Breakpoint (ADDBKP) command to add breakpoints to the program you want debugged.
You can specify up to 10 statement identifiers on the one Add Breakpoint (ADDBKP) command. The program variables specified on an Add Breakpoint (ADDBKP) command apply only to the breakpoints specified on that command. Up to 10 variables can be specified in one Add Breakpoint (ADDBKP) command.
You can also specify the name of the program to which the breakpoint is to be added. If you do not specify the name of the program that you want the breakpoint added to, the breakpoint is added to the default program specified on the STRDBG, CHGDBG, or ADDPGM command.
To add a breakpoint to a program, specify a statement identifier, which can be:
When you add a breakpoint to a program, you can also specify program variables whose values or partial values you want to display when the breakpoint is reached. These variables can be shown in character or hexadecimal format.
Program processing stops at a breakpoint before the instruction is processed. For an interactive job, the system displays what breakpoint the program has stopped at and, if requested, the values of the program variables.
In high-level language programs, different statements and labels may be mapped to the same internal instruction. This happens when there are several inoperable statements (such as DO and ENDDO) following one another in a program. You can use the IRP list to determine which statements or labels are mapped to the same instruction.
The result of different statements being mapped to the same instruction is that a breakpoint being added may redefine a previous breakpoint that was added for a different statement. When this occurs, a new breakpoint replaces the previously added breakpoint, that is, the previous breakpoint is removed and the new breakpoint is added. After this information is displayed, you can do any of the following:
For a batch job, a breakpoint program can be called when a breakpoint is reached. You must create this breakpoint program to handle the breakpoint information. The breakpoint information is passed to the breakpoint program. The breakpoint program is another program such as a CL program that can contain the same commands (requests for function) that you would have entered interactively for an interactive job. For example, the program can display and change variables or add and remove breakpoints. Any function valid in a batch job can be requested. When the breakpoint program completes processing, the program being debugged continues.
A message is recorded in the job log for every breakpoint for the debug job.
The following Add Breakpoint (ADDBKP) commands add breakpoints to the program CUS310. CUS310 is the default program, so it does not have to be specified. The value of the variable &ARBAL is shown when the second breakpoint is reached.
ADDBKP STMT(900)
ADDBKP STMT(2200) PGMVAR('&ARBAL')
The source for CUS310 looks like this:
5728PW1 R01M00 880101 SEU SOURCE LISTING
SOURCE FILE . . . . . . . QGPL/QCLSRC
MEMBER . . . . . . . . . CUS310
SEQNBR*...+... 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+...
6 ...+... 7 ...+... 8 ...
100 PGM PARM(&NBRITEMS &ITEMPRC &PARBAL &PTOTBAL)
200 DCL VAR(&PARBAL) TYPE(*DEC) LEN(15 5) /*
INPUT AREA INV BALANCE */
300 DCL VAR(&PTOTBAL) TYPE(*DEC) LEN(15 5) /*
INPUT TOTAL INV BALANCE*/
400 DCL VAR(&NBRITEMS) TYPE(*DEC) LEN(15 5) /*
NUMBER OF ITEMS */
500 DCL VAR(&ITEMPRC) TYPE(*DEC) LEN(15 5) /*
PRICE OF THE ITEM */
600 DCL VAR(&ARBAL) TYPE(*DEC) LEN(5 2) /*
AREA INVENTORY BALANCE */
700 DCL VAR(&TOTBAL) TYPE(*DEC) LEN(5 2) /*
TOTAL INVENTORY BALANCE*/
800 DCL VAR(&TOTITEM) TYPE(*DEC) LEN(5 2) /*
TOTAL PRICE OF ITEMS */
900 CHGVAR VAR(&ARBAL) VALUE(&PARBAL)
1000 CHGVAR VAR(&TOTBAL) VALUE(&PTOTBAL)
1100 IF COND(&NBRITEMS *EQ 0) THEN(DO)
1200 SNDPGMMSG MSG('The number of items is zero. This item +
1300 should be ordered.') TOMSGQ(INVLIB/INVQUEUE)
1400 GOTO CMDLBL(EXIT)
1500 ENDDO
1600 CHGVAR VAR(&TOTITEM) VALUE(&NBRITEMS * &ITEMPRC)
1700 IF COND(&NBRITEMS *GT 50) THEN(DO)
1800 SNDPGMMSG MSG('Too much inventory for this item.') +
1900 TOMSGQ(INVLIB/INVQUEUE)
2000 ENDDO
2100 CHGVAR VAR(&ARBAL) VALUE(&ARBAL + &TOTITEM)
2200 IF COND(&ARBAL *GT 1000) THEN(DO)
2300 SNDPGMMSG MSG('The area has too much money in +
2400 inventory.') TOMSGQ(INVLIB/INVQUEUE)
2500 ENDDO
2600 CHGVAR VAR(&TOTBAL) VALUE(&TOTBAL + &TOTITEM)
2700 EXIT: ENDPGM
The following is displayed as a result of reaching the first breakpoint:
Display Breakpoint Statement/Instruction . . . . . . . . . : 900 /0009 Program . . . . . . . . . . . . . . . . : CUS310 Recursion level . . . . . . . . . . . . : 1 Press Enter to continue. F3=Exit program F10=Command entry
The following is displayed as a result of reaching the second breakpoint:
Display Breakpoint Statement/Instruction . . . . . . . . . : 2200 /0022 Program . . . . . . . . . . . . . . . . : CUS310 Recursion level . . . . . . . . . . . . : 1 Start position . . . . . . . . . . . . : 1 Format . . . . . . . . . . . . . . . . : *CHAR Length . . . . . . . . . . . . . . . . : *DCL Variable . . . . . . . . . . . . . . . : &ARBAL Type . . . . . . . . . . . . . . . . : PACKED Length . . . . . . . . . . . . . . . : 5 2 '610.00' Press Enter to continue. F3=Exit program F10=Command entry
The variable &ARBAL is shown. (Note that the value of &ARBAL will vary depending on the parameter values passed to the program.) You can press F10 to display the command entry display so that you could change the value of the variable &ARBAL to alter your program's processing. You use the Change Program Variable (CHGPGMVAR) command to change the value of a variable.