From R/2 to R/3 (SAP Library - SAP Communication: CPI-C Programming (BC-CST-GW))

From R/2 to R/3

Purpose

An ABAP program in an R/2 System starts an ABAP program in an R/3 System and exchanges data with this program.

You can start the target program from the R/2 host via an SAP communications program.

Prerequisites

With this constellation, you must note the following guidelines:

Using the RFC interface:

The side info tables XCOM and RFCD must be configured.

The destination of the function call must match the corresponding entry in XCOM and RFCD.

The called function must exist as a function module in the ABAP function library and have the "remote" ID.

For more details on the RFC interface, refer to the documentation Remote Communications.

Using the CPI-C interface

The SAP Gateway must be in use.

Note

Special Features under BS2000

The tasks SAPGWHO (program gwhost) are started by the R/2 System at initialization. These tasks build the connection to an SAP Gateway under UNIX (not under BS2000).

Process flow

In BS2000 the SAPGWHO jobs (program gwhost) perform the functions of the communications program when connection is set up by the R/2 System.

The process consists of the following steps:

The calling ABAP program reads the TP name in table XCOM and starts the SAPGWHO jobs.
The communications program sets up a Conversation with a SAP Gateway on the UNIX computer.
The SAP Gateway starts the actual target program.

Side info files must be configured on the UNIX computer and on the BS2000 host.

For details on the configuration of side info files, refer to the documentation

BC SAP Communication: Configuration under the following topic: Connection Setup by the R/2 System.