Allocating a session to the conversation

Initially, there is no conversation, and therefore no conversation state. By issuing a GDS ALLOCATE command, the front-end transaction acquires a session to start a new conversation.

RETCODE should be checked to ensure that a session has really been allocated. If successfully allocated (RETCODE = X'00' ), the conversation is in allocated state (state 1) and the session identifier ( convid ) is placed in the data area specified on the CONVID parameter.

The convid must be used in subsequent commands for this conversation. Figure 1 shows an example of a GDS ALLOCATE command.

Note: If the remote system is using z/OS® Communications Server persistent session support, you may need to code a timeout value on the GDS ALLOCATE command. See Effect of z/OS Communications Server persistent sessions support for DTP conversations on APPC sessions.