gtpc2manC/C++ Language Support User's Guide

TPF/APPC Mapped Conversation Interface Overview

The TPF/APPC mapped interface is based on the communication element of the SAA's Common Programming Interface (CPI). Although TPF/APPC does not fully conform to CPI Communications, standard CPI Communications programs can be converted easily, provided the programs do not use the features described below that TPF does not support. See the Systems Application Architecture Common Programming Interface Communications Reference for more information about CPI Communications.

The TPF/APPC mapped interface differs from CPI Communications in the following:

As a result of these changes, some CPI Communications functions and characteristics no longer have meaning or can have only one value. Therefore, the following functions are not supported:

The following characteristics are not supported:

Characteristics

Characteristics are values that are stored internally and keep the transaction program from having to specify the same values on function calls over and over. There are special functions to change and examine the values of the various characteristics. The characteristics, which are shown in italics throughout this chapter, are:

The set functions provide details about these characteristics. In addition, the programming considerations for each function list any characteristics that are affected by that function.

Conversation States

The following is a list of the conversation states for the TPF/APPC mapped conversations:

reset
There is no conversation.

initialize
The conversation is initialized but not allocated.

send
The program can send data.

send-pending
The cmrcv (RECEIVE) function returned data_received with the value CM_COMPLETE_DATA_RECEIVED and status_received with the value CM_SEND_RECEIVED. When a conversation is in this state, the error_direction characteristic affects how an error is reported to the remote program. (See cmsed-Set the Error_Direction Characteristic.)

receive
The program can receive data.

confirm
The transaction program received a confirmation request from the remote transaction program.

confirm-send
The remote transaction program sent a cmptr (PREPARE_TO_RECEIVE) request with prepare_to_receive_type set to CM_PREP_TO_RECEIVE_CONFIRM, or with prepare_to_receive_type set to CM_PREP_TO_RECEIVE_SYNC_LEVEL and sync_level set to CM_CONFIRM. If the local transaction program does a cmcfmd (CONFIRMED), the PREPARE_TO_RECEIVE takes effect.

confirm-deallocate
The transaction program received a confirmation request and a deallocation notification from the remote program. If the local program replies with a cmcfmd (CONFIRMED), the deallocation takes effect.
Note:
Because the TPF system does not support sync point, the following states defined by CPI Communications are not used:

Side Information Table

The side information table holds combinations of partner LU names, remote transaction program names, and mode names. Each combination is identified by a unique symbolic destination name. The side information table offline program (CHQI) provides a way of generating the side information table, verifying the syntax of the entries before bringing them online, and managing the data contained in the online information table. You can also build or modify the table online using the ZNSID command. See the TPF ACF/SNA Data Communications Reference for more information about the CHQI program. See TPF Operations for more information about ZNSID.