The
3270 commands are either write commands, which instruct the EPI to
process the data, or read commands, which instruct the EPI to reply
with data.
On a CICS_EPI_EVENT_SEND event, the command is one of the
following 3270 write commands:
- Write
- Erase/Write
- Erase/Write Alternate
- Erase All Unprotected.
The first three commands are followed by a write control character
(WCC) and data. An Erase All Unprotected command has neither WCC nor
data. The Write Structured Field command is not generated by CICS® and
is therefore not supported for the EPI.
Command
(1 byte)
|
Write control
character
(1 byte)
|
Data buffer
(variable length)
|
The contents of the data buffer consist of:
- ASCII displayable characters with embedded 3270 control characters,
when it is passed from an EXEC CICS SEND
MAP command.
- User-specified data, when it is passed from an EXEC CICS SEND
command.
A CICS_EPI_EVENT_CONVERSE event
specifies a read command. The contents of the data stream vary with
the source of the event, as follows:
- If the event is the result of an EXEC CICS RECEIVE
command, the data buffer might
contain data sent by the transaction, or it might be empty. The EPI
program should reply when the data to be sent is available.
- If the event is the result of an EXEC CICS RECEIVE
BUFFER command, the
data buffer contains the 3270 Read Buffer command. This should be
processed as described in the 3270 Data Stream Programmer’s Reference.