GDDM high-performance alphanumerics

GDDM V3R2 Base Application Programming Reference

GDDM high-performance alphanumerics

GDDM V3R2 Base Application Programming Reference
SC33-0868-02

High-performance alphanumerics (HPA) is another way of doing alphanumerics in GDDM, and is intended for complex applications that require minimum instruction path length within GDDM.

The application program may not mix mapped and procedural alphanumeric field definitions with HPA field definitions on the same GDDM page.

The style of application programming interface used by HPA differs from that used by other parts of GDDM, such as procedural alphanumerics. When using procedural alphanumerics, application programs use many API calls to describe the data to GDDM for output, and also to determine the data input by the device operator. In contrast, the HPA application builds a data structure to describe all the data, and passes that to GDDM for output. Also, the data input by the device operator is returned to the HPA application in the same data structure. Changes to the data are indicated through status indicators that are part of the structure.

Note: Although HPA can be used from REXX, its use is not recommended, except for prototyping, because the instruction-path length in the interpreter interface to GDDM is significant.

Subtopics:

17.1 HPA data structure

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