PL/I Basic Demo Session › Detect and Prevent an Abend

Detect and Prevent an Abend

The next screen is not displayed by the PL/I demo. It is a diagnostic screen, called a breakpoint display, which is displayed by CA InterTest for CICS when it detects an error.

CA InterTest for CICS Release 9.1.00   - PROTSYM FILE  ABEND DETECTED BREAKPOINT        
COMMAND ===>                                                                   
Program= PLIDEMO  Option #       Stmt #                             Margin= 01 
                                        Search=                                
-------------------------------------------------------------------------------
 _____ TASKNUM                         | ?00000.                               
---------+---------------------------------------------------------------------
 _   636.1            CONTINUE_TASK:                                           
 _   637.1               MAPNUM  = '00';                                       
 A   ==>.1     1         TASKNUM = TASKNUM + 1;      ==>                       
     ==> ASRA ABEND (0C7) detected and prevented. Caused by invalid decimal    
     ==> arithmetic data format.                                               
     ==>                                                                       
     ==>      Press PF1 for a detailed description.                            
     ==>                                                                       
                                                                               
 _   639.1     1         IF TASKNUM > 2 THEN                                   
 _   640.1     1            GOTO END_SESSION;                                  
 _   641.1     1         IF TASKNUM = 1 THEN                                   
 _   642.1     1            GOTO SENDSCR3;                                     
 _   643.1     1         GOTO END_SESSION;                                     
 _   644.1                                                                     
 _   645.1     1      SENDSCR3:                           /** ASRA CONGRATULAT 
 _   646.1                   /* EXEC CICS SEND MAP('DASRA'

Notice that CA InterTest for CICS has highlighted an ADD instruction and displayed a message below it. Execution of that ADD instruction triggered an ASRA abend. CA InterTest for CICS prevented the abend and then displayed the diagnostic screen you are currently viewing.

When CA InterTest for CICS stops program execution, we say that it halts the program at a breakpoint. It does this automatically, as in the example, or it halts a program at a breakpoint set by you, the programmer. The A to the left of the assignment statement indicates that the current halt in program execution is an Automatic breakpoint—not one set by you.

Now look at the highlighted message. It explains that the problem was caused by improperly formatted data. Which data? Since TASKNUM = TASKNUM + 1 triggered the breakpoint, it is likely that TASKNUM contains improperly formatted data.

So far, CA InterTest for CICS has prevented PLIDEMO from abending and identified the problem. Next, you will perform the following procedures:

1. Determine the cause of the error.
2. Dynamically correct the error by changing the value of TASKNUM.