Chapter 1: Introduction

Processing an RPC

When a client sends an RPC, a typical mainframe server application (short transaction) performs the tasks in Table 1-2.

**Table 1-2: Functions to process RPCs**
Task	Function
1. Prepare for incoming requests. Initialize the Gateway-Library environment. Specify the type of IMS TM transaction (used with IMS TM transactions only).	TDINIT TDSETPT
2. Accept the incoming request. Accept the incoming request.	TDACCEPT
3. Handle incoming parameters. Determine how many parameters were sent. Define variables for storing parameter information (datatype, length, data). Retrieve the parameter. Loop until all parameters are retrieved.	TDNUMPRM TDINFPRM TDRCVPRM
4. Process the request. Perform the requested task(s).
5. Prepare to return results to the client. Set the length and address of each return parameter (Loop until all parameters are described). Describe each column in a row to be returned (Loop until all columns are retrieved).	TDSETPRM TDESCRIB
6. Return data to the client. Send data to the client, one row at a time (Loop until all rows are sent). Send the return parameters, tell the client when results are finished, and close the connection.	TDSNDROW
7. End the conversation. Free the TDPROC structure. Free the MVS storage (required with IMS TM; optional but recommended with CICS).	TDFREE TDTERM