Types of conversion

The possible types of conversion are standard conversion, no conversion, and user-defined nonstandard conversion.

Standard conversion
This applies to:
  • Single-byte character sets (SBCS)
  • Graphic or double-byte character sets (DBCS)
  • Mixed character sets (containing SBCS and DBCS data)
  • Multi-byte character sets (MBCS)
  • By default, to binary data in INTEL format.
No conversion
This applies to:
  • Character data encoded as UCS-2 or UTF-8
  • By default, to binary data in z/Architecture® format
  • Packed decimal data.
User-defined nonstandard conversion
You can apply nonstandard data conversion by writing your own version of the user-replaceable conversion program.

You can apply user-defined conversion to selected fields, and leave others to be converted by the CICS® standard conversion program.

For CICS Transaction Server for z/OS®, you can provide either:
  1. Your own, customized, version of DFHUCNV, or
  2. One or more differently-named conversion programs

If the nonstandard conversion applies only to character data, you may not need to write your own data conversion program. Instead, you can create your own conversion tables for use with the standard conversion program, DFHCCNV. See User-defined conversion tables.

Attention: Your user-supplied conversion program must not convert any data that the standard conversion program attempts to convert. Converting data twice gives unpredictable results. To avoid this, your conversion program must convert only fields defined as DATATYP=USERDATA (see the DATATYP option of the DFHCNV TYPE=FIELD macro).