Pathway/iTS TCP and Terminal Programming Guide

Programming for Intelligent Devices
Compaq NonStop™ Pathway/iTS TCP and Terminal Programming Guide—426751-001
6-6
Using Message Delimiters
For example, suppose you want to send the following message to the external device or
process:
BILL WINN,GIUSEPPE PINELLI,JOE BLOW,LING CHIN,SARAH HARRAH,
To do so, you would move the following values to the specified working-storage
locations:
'BILL WINN' ws-item1-data
'9' ws-item1-cnt
'GIUSEPPE PINELLI' ws-item2-data
'16' ws-item2-cnt
'JOE BLOW' ws-item3-data
'8' ws-item3-cnt
'LING CHIN' ws-item4-data
'9' ws-item4-cnt
'SARAH HARRAH' ws-item5-data
'12' ws-item5-cnt
and then issue a SEND MESSAGE statement such as:
SEND MESSAGE msg-format4
ON ERROR GO TO error-exit.
Before moving a data element from working storage to its output buffer, the TCP
examines the location referenced by the associated RESULTING COUNT clause to find
out how many bytes of data the field actually contains. After retrieving the specified
number of bytes from the particular working-storage location, the TCP appends a field-
delimiter character (in this case, a comma) to the end of the outbound field.
Thus, you can directly control the placement of field delimiters in the output stream.
Using Message Delimiters
The use of a RESULTING COUNT clause at the message level allows you to determine,
on input, how long an incoming variable-length record was, without having to do a
backward search through your working-storage data structure.
If the external device or process requires the message to include a message delimiter,
you must declare the message delimiter in your message template; otherwise, the TCP
mistakes the message-delimiter characters for actual data.
For example, if the external device or process requires that each message be terminated
by a colon (:), you must change the beginning of the preceding sample message template
declaration to the following:
01 msg-format4
MESSAGE IS DELIMITED
MESSAGE DELIMITER IS ":".