COBOL compiler option NUMPROC

NUMPROC(NOPFD):This makes the compiler to perform invalid sign processing

NUMPROC(PFD)       :This option bypasses the invalid sign processing.

 

The difference between the two options is explained through the below example

 

CODE:

 

WORKING-STORAGE SECTION.                        

01 WS-VAR                   PIC X(2) VALUE "5-".

01 WS-VAR-1                 PIC 9(2).           

 

PROCEDURE DIVISION.

MOVE WS-VAR TO WS-VAR-1

DISPLAY WS-VAR-1.       

IF WS-VAR-1 IS NUMERIC               

   DISPLAY "THE FIELD IS NUMERIC"    

ELSE                                 

   DISPLAY "THE FIELD IS NOT NUMERIC"

END-IF.

 

OUTPUT  When   NUMPROC(NOPFD) is used:

50

THE FIELD IS NUMERIC

 

OUTPUT  When   NUMPROC(PFD) is used:

 5-

 THE FIELD IS NOT NUMERIC                        

 

Depending upon the option used the same code produces different results.:

Reason

 

When NOPFD option is used it performs invalid sign processing. In our case “5-“ hex value is “F560”.The sign value for the field is X’6’ which is an invalid sign value(valid sign values: X’C’-positive.X’D’-negative,X’F’-unsigned and by default they occupy higher order 4 bits of last byte).The general rule in data movement is, when sending data item is alphanumeric field and the receiving field is unsigend numeric,the sending field is treated as unsigned numeric(this is the reason we are able to move non-numeric value stored in Alphanumeric field to numeric field and not move non-numeric value directly to the numeric field).Since the sending field is treated as unsigned numeric the invalid sign value X’6’ is converted to X’F’ and the value becomes “F5F0” which is 50 in decimal and so our output.

 

When PFD option is used the invalid sign processing is not done the value is directly moved to the numeric field without any processing.

 

Conclusion:

 

This kind of situation may occur mainly in CICS programs where the screen field is defined as alphanumeric.When value is entered wrongly in the screen field and if numeric condition is checked for the field, correct results will be produced depending on the correct option used(PFD in our case).Disadvantage in using NOPFD option is ,it increases the object code size and there could be an increase in run-time overhead to validate all signed data. So depending on our requirements appropriate option could be used.