HP 3000 Manuals HP 3000 Manuals
Data Items (VSC2) (MF) DBCS Data Items There is a class of data additional to the classes described in Chapter 2: it is called DBCS. It includes two data categories: DBCS and DBCS edited. A data item of class DBCS is described by using the USAGE DISPLAY-1 clause. An item with this clause can have only the characters "G" and "B" in its PICTURE character-string. A "G" represents a DBCS character position; "B" is an editing character, and indicates a position that will always have a DBCS space inserted in editing. An item whose PICTURE character-string is all "G"s is of category DBCS; an item whose PICTURE character-string contains both "G" s and "B"s is of category DBCS edited. Note that each "G" or "B" represents one 2-byte character position. Except where otherwise stated, the length of the data item for all purposes is the number of "G" s and "B"s in its PICTURE character-string. Data items of class DBCS can be used wherever data items of class alphanumeric can be used, subject to rules and exceptions given in the appropriate places in this chapter. Mixed Data Items DBCS characters can be included in data stored in data items of category alphanumeric. In such data, SBCS characters are represented by SBCS codes and DBCS characters by DBCS codes. Each space character is represented by the SBCS code for space. On input and output both the SBCS and the DBCS codes will be recognized. The first byte of a DBCS code is never a valid SBCS code; hence the two can be used together without confusion. But in operations within the program the data will be treated as ordinary alphanumeric data. It is the programmer's responsibility to ensure that the two halves of a DBCS code do not get separated. The length of the data item for all purposes is its length in bytes.