Pathway/iTS TCP and Terminal Programming Guide

Writing User Conversion Procedures

Compaq NonStop™ Pathway/iTS TCP and Terminal Programming Guide—426751-001

4-14

Intelligent Device Output Procedures

When USER CONVERSION is specified in a message entry, the TCP calls the numeric

procedure for data moved from a numeric data field in working storage; it calls the

alphanumeric procedure for data moved from an alphanumeric data field in working

storage.

When USER CONVERSION is specified in a SEND MESSAGE statement, the TCP

calls the alphanumeric procedure regardless of the message data type. The user

procedures are performed after any standard conversion of the data.

If a USER CONVERSION clause is specified for both a Message Section message field

and the SEND MESSAGE statement that sends the message, the TCP first calls the

procedure for the message field, then calls the procedure for the message, and finally

calls the procedure for the SEND MESSAGE statement. This calling order is the

inverse of the order for intelligent device input procedures.

Figure 4-9

illustrates the data flow of the processing of Message Section items on

output. The sequence of events performed for data output to an intelligent device is

shown; processing steps relevant to user conversion routines are highlighted.

Most of the parameters for the two output procedures are the same; they differ in their

internal data representation and in that alphanumeric items can be justified and numeric

Figure 4-9. Message Output to an Intelligent Device

MESSAGE SECTION

MESSAGE SECTION message TCP

TCP message Intelligent Device

CDT 049.CDD

WORKING-STORAGE SECTION

Field Level

Group Level

Message Level

Process field PRESENT IF

FROM/USING source location

Field conversion to

MESSAGE SECTION format

Field Level USER CONVERSION

FIELD LENGTH/append

FIELD-SEPARATOR

OCCURS Processing

Message Level USER CONVERSION

SEND MESSAGE Verb’s

USER CONVERSION

VARYING1 and VARYING2 handling