Writing APPC applications for CICS

Applications can issue CICS commands for APPC conversations and so control the allocation and use of an APPC session. To do this, a program must be aware of the state of the conversation over the intersystem link at any given time. The CICS commands used to control an APPC conversation, along with their corresponding Smalltalk classes, are as follows:

CICS command	Smalltalk class
ALLOCATE	CICSAppcallocate, CICSAppcallocateResult
CONNECT PROCESS	CICSAppcconnectprocess, CICSAppcconnectprocessResult
CONVERSE	CICSAppcconverse, CICSAppcconverseResult
EXTRACT ATTRIBUTES	CICSAppcextractattributes, CICSAppcextractattributesResult
EXTRACT PROCESS	CICSAppcextractprocess, CICSAppcextractprocessResult
FREE	CICSAppcfree, CICSAppcfreeResult
ISSUE ABEND	CICSAppcissueabend, CICSAppcissueabendResult
ISSUE CONFIRMATION	CICSAppcissueconfirmation, CICSAppcissueconfirmationResult
ISSUE ERROR	CICSAppcissueerror, CICSAppcissueerrorResult
ISSUE SIGNAL	CICSAppcissuesignal, CICSAppcissuesignalResult
RECEIVE	CICSAppcreceive, CICSAppcreceiveResult
SEND	CICSAppcsend, CICSAppcsendResult
WAIT CONVID	CICSAppcwait, CICSAppcwaitResult

See the Server Guide for a description of the CICS commands and their command options supported by VA Smalltalk Server.

The process below assumes that you have set up the appropriate side information on the client and have defined the transaction program to the server. For more information about writing APPC programs for CICS, see the CICS documentation. The sample program shows a simple two-way communication between a front-end transaction running from a workstation and a back-end transaction residing on CICS Transaction Server.