DDS Display Files--UCS-2 Level 1 Considerations

This section describes the UCS-2 Level 1 considerations for the positional entries and keyword entries for display files.

UCS-2 Level 1 data is not supported on display devices that currently support the 5250 data stream. Therefore, conversions between the UCS-2 Level 1 data and EBCDIC are necessary during I/O. On output, the UCS-2 Level 1 data will be converted to the CCSID of the device. On input, the data is converted from the device CCSID to the UCS-2 Level 1 CCSID.

Since the device CCSID, which is determined from the device configuration, determines what the UCS-2 Level 1 data is converted to, the converted data will appear differently on different devices. For example, a UCS-2 Level 1 character which maps to a SBCS character will be displayed as a DBCS replacement character on a graphic-DBCS capable device. On a DBCS or SBCS capable device, the character will appear as a SBCS character. A UCS-2 Level 1 character which maps to a DBCS character will be displayed as a graphic-DBCS character on a graphic-DBCS capable device. On a DBCS device, a DBCS character will displayed and bracketed (enclosed in a shift-out and shift-in). A SBCS replacement character will be displayed on a SBCS device.

It is also suggested that all UCS-2 capable fields are initialized in the output buffer before writing the fields to the screen. Unpredictable results may occur if default initialization is allowed to take place.