The topic describes, by position, DDS for describing display files.
Positions not mentioned have no special considerations for Unicode.
Length (positions 30 through 34)
Specify the length
of the field in these positions. The length of a field containing Unicode
data can range from 1 through 16 381 code units.
When
determining the program length of a field containing Unicode data, consider
the following rules:
- Each Unicode code unit is 2 bytes long.
- The program length of the field is specified in number of Unicode code
units. For example, a field containing 3 Unicode code units has 6 bytes of
data.
- The field's default display length is equal to the field's program length
or 2 times the number of Unicode code units.
- After converting between Unicode data and EBCDIC, the resulting data can
be equal to, longer or shorter than the original length data before the conversion,
depending upon the CCSID of the device. For example, 1 Unicode code unit is
composed of 2 bytes of data. That code unit might convert to 1 SBCS character
composed of 1 byte of data, 1 graphic-DBCS character composed of 2 bytes of
data, or 1 bracketed DBCS character composed of 4 bytes of data.
- The field's display length can be specified separately from the program
length by using the alternate-field-length parm on the CCSID keyword.
Data type (position 35)
The only valid data type
for Unicode data is the G data type.
- G (Graphic)
- Type G in combination with the CCSID keyword to specify this field contains
Unicode data.
Normally, by specifying G, the field contains graphic-DBCS
data. In combination with the CCSID keyword, the field now contains Unicode
data. On output, the data is mapped to corresponding characters in the CCSID
that the device is configured as. On input, the data is mapped to corresponding
Unicode code units.
Decimal positions (positions 36 and 37)
Leave these
positions blank when using Unicode data.