Conversation States

The state of a conversation depends on what a transaction program or its partner has just done and determines what actions a TP can take next.

The basic conversation states in APPC are:

State: Description
Reset: The initial state, before communications begin or after they end.
Send: The state in which a program is allowed to send data.
Receive: The state in which a program is allowed to receive data.
Confirm: The state in which a program must respond to its partner.

Some of the callable services cause a transition from one state to another. For example, when a local program in Reset state issues a successful Allocate call, the local program goes into Send state. The partner goes into Receive state when it issues CMACCP or the Get_Conversation service to accept the conversation.

APPC/MVS implements these states slightly differently for its CPI Communications and MVS TP conversation calls. For detailed descriptions of the conversation states that apply to all the individual conversation calls, see the following:

For CPI Communications, the section about CPI communications terms and concepts, and the state table in CPI-C Reference
For MVS TP conversation calls, The APPC/MVS Programming Interface and APPC/MVS Conversation State Table.