ZONEDATA

The ZONEDATA option tells the compiler whether the data in USAGE DISPLAY and PACKED-DECIMAL data items is valid, and if not, what the behavior of the compiler should be.

Since most users have valid data in their USAGE DISPLAY and USAGE PACKED-DECIMAL data items, most users should use ZONEDATA(PFD), even if they use NUMPROC(NOPFD). Even if you find that your programs are processing invalid data at run time (using the NUMCHECK compiler option), you should change your programs to avoid processing invalid data, and use ZONEDATA(PFD).
Note: The ZONEDATA option is deprecated but is tolerated for compatibility, and it is replaced by the INVDATA option.
When the ZONEDATA option is specified, it is mapped to the equivalent INVDATA option as follows:
ZONEDATA(PFD)   = NOINVDATA
ZONEDATA(NOPFD) = INVDATA(NOFORCENUMCMP,CLEANSIGN) (or simply INVDATA)
ZONEDATA(MIG)   = INVDATA(FORCENUMCMP,CLEANSIGN)

ZONEDATA option syntax

Read syntax diagramSkip visual syntax diagramZONEDATA(PFDMIGNOPFD)

Default is: ZONEDATA(PFD)

Abbreviations are: ZD(PFD) | ZD(MIG) | ZD(NOPFD)

Each digit of a valid zoned decimal number is represented by a single byte from X'F0' through X'F9'. The 4 high-order bits of each byte are zone bits, and the 4 low-order bits of each byte contain the value of the digit. The 4 high-order bits of the low-order byte for SIGN TRAILING represent the sign of the item. The sign is in the high-order byte with SIGN LEADING, or in a separate byte for SIGN IS SEPARATE.

ZONEDATA(PFD)

When the ZONEDATA(PFD) option is in effect, the compiler assumes that all data in USAGE DISPLAY and PACKED-DECIMAL data items is valid, and generates the most efficient code possible to make numeric comparisons. For example, the compiler might generate a string comparison to avoid numeric conversion.

ZONEDATA(MIG)

When the ZONEDATA(MIG) option is in effect, the compiler generates instructions to do numeric comparisons that ignore the zone bits of each digit in zoned decimal data items. For example, the zoned decimal value is converted to packed-decimal with a PACK instruction before the comparison. The compiler will also avoid performing known optimizations that might produce a different result than COBOL V4 (or earlier versions) when a zoned decimal or packed decimal data item has invalid digits or an invalid sign code, or when a zoned decimal data item has invalid zone bits.

ZONEDATA(NOPFD)
When the ZONEDATA(NOPFD) option is in effect, the compiler generates instructions for numeric comparisons or an alphanumeric comparison of zoned decimal data in the same manner as COBOL V4 (or earlier versions) does when using NUMPROC(NOPFD | PFD) with COBOL V4 (or earlier versions) :
  • In the cases where COBOL V4 (or earlier versions) considered the zone bits, the compiler generates an alphanumeric comparison which will also consider the zone bits of each digit in zoned decimal data items. The zoned decimal value remains as zoned decimal.
  • In the cases where COBOL V4 (or earlier versions) ignored the zone bits, the compiler generates numeric comparisons that ignore the zone bits of each digit in zoned decimal data items. The zoned decimal value is converted to packed-decimal with a PACK instruction before the comparison.
In order for the compiler to handle zone bits in the same way as COBOL V4 (or earlier versions) did when generating comparisons of zoned decimal data, the NUMPROC suboption used in COBOL V6 must match the NUMPROC suboption used in COBOL V4 (or earlier versions):
  • To get the COBOL V4 (or earlier versions) NUMPROC(NOPFD) behavior in COBOL V6, use ZONEDATA(NOPFD) and NUMPROC(NOPFD) in COBOL V6.
  • To get the COBOL V4 (or earlier versions) NUMPROC(PFD) behavior in COBOL V6, use ZONEDATA(NOPFD) and NUMPROC(PFD) in COBOL V6.

The compiler will also avoid performing known optimizations that might produce a different result than COBOL V4 (or earlier versions) when a zoned decimal or packed decimal data item has invalid digits or an invalid sign code, or when a zoned decimal data item has invalid zone bits.

Note: The sign code must be a valid sign code according to the NUMPROC compiler option setting. In addition, the low-order byte must have a valid zone (x'F') for unsigned and signed with either SIGN IS LEADING or SIGN IS SEPARATE.
Note: The ZONEDATA option affects the behavior of MOVE statements, comparisons, and computations for USAGE DISPLAY or PACKED-DECIMAL data items that could contain invalid digits, an invalid sign code, or invalid zone bits.
In the following example, you can see a data item with an invalid zone bit 4 in the zone bits in the middle of data item VALUE1, forced in by REDEFINES: 
 77  VALUE0    PIC X(4) VALUE '00 0'.              *>  x'F0F040F0'
 77  VALUE1    REDEFINES VALUE0 PIC 9(4). 
 PROCEDURE DIVISION.
     IF VALUE1 = ZERO                                               
        DISPLAY 'ZONEDATA(MIG) is in effect ' VALUE1                
     ELSE                                                           
        DISPLAY 'ZONEDATA(NOPFD | PFD) is in effect '  VALUE1                
     END-IF
In this example:
  • With COBOL V4 (or earlier versions) or earlier versions, the test is true if the NUMPROC(MIG) option is used, and false for NUMPROC(NOPFD | PFD).
  • With COBOL V5 or later versions:
    • When using ZONEDATA(PFD), the test is true at OPT(0) and false at OPT(1 | 2).
    • When using ZONEDATA(NOPFD), the test is false at any OPT setting.
In all, to ease your migration to COBOL V6:
  • If your digits, sign codes, and zone bits are valid, use ZONEDATA(PFD) and the same NUMPROC setting that you used with COBOL V4 (or earlier versions) when using COBOL V6.
  • If you have invalid digits, invalid sign codes, or invalid zone bits in your data, change your programs or systems so that your programs do not have invalid data in numeric data items at run time.

    Once you have corrected your programs or systems, you can use the preferred ZONEDATA(PFD) option. Only if you cannot contain this work and must continue to run with invalid data, consider the following choices for ZONEDATA:

    • If you used NUMPROC(MIG) with COBOL V4 (or earlier versions) , use ZONEDATA(MIG) and NUMPROC(NOPFD) with COBOL V6.
    • If you used NUMPROC(NOPFD) with COBOL V4 (or earlier versions) , use ZONEDATA(NOPFD) and NUMPROC(NOPFD) with COBOL V6.
    • If you used NUMPROC(PFD) with COBOL V4 (or earlier versions) , use ZONEDATA(NOPFD) and NUMPROC(PFD) with COBOL V6.
Note: It is not always possible to entirely match the behavior of the old compiler even with these options when faced with clearly invalid data. For example, even for compares, ZONEDATA(NOPFD) isn't going to give the same result in all cases as COBOL V4.

Performance considerations: ZONEDATA(PFD) gives better runtime performance than ZONEDATA(NOPFD | MIG) does. ZONEDATA(NOPFD | MIG) disables some of the optimizations that NUMPROC(PFD) can give.

Related tasks  
Checking for incompatible data (numeric class test)
Related references  
NUMCHECK
NUMPROC  
ZONECHECK