Processing Double Byte Character Set Data › DBCS Support in NCL

DBCS Support in NCL

Support for DBCS data manipulation in NCL is activated by the following &CONTROL options:

• &CONTROL DBCS
• &CONTROL DBCSN
• &CONTROL DBCSP

All three of these options alter the way in which NCL operates, to ensure that DBCS data is recognized and preserved. When any of these options are in effect, the string manipulation functions of NCL check for the presence of DBCS data. If a string is padded or truncated, the shift characters are automatically preserved-without the shift characters it is impossible to identify the DBCS

Note: On Hitachi systems, the character X'40' is considered to be a neutral character which can appear in both SBCS or DBCS data. When NCL calculates character boundaries in DBCS data, single X'40' characters are considered valid if the NCL procedure is executing on behalf of a user logged-on from a Hitachi 560/20 terminal, or if the procedure is executing in a background region (for example, BSYS region) and the operating system on which the region is executing is VOS3.

Terminals capable of displaying DBCS data exhibit differing display characteristics. Terminals such as the IBM 5550 family display shift characters as blank fields on the screen. On Fujitsu and Hitachi terminals the shift characters take no screen position.

NCL provides for these differing characteristics according to a control setting of the &CONTROL verb:

• &CONTROL DBCS treats shift characters as significant, including them in calculations of length and offset
• &CONTROL DBCSN considers shift characters are not significant; they are ignored in length and offset calculations
• &CONTROL DBCSP chooses between these options depending on the processing environment
• &CONTROL NODBCS treats all data as SBCS (valid mixed DBCS/SBCS data strings could be corrupted)