Server Processing: An Overview

The following list presents an overview of the main steps that servers follow when processing inbound conversations. Later chapters of this book provide the details for performing these steps.

1. Becoming a server —

   An application becomes an APPC/MVS server when it registers to serve inbound allocate requests (through the Register_For_Allocates service). When the server's Register_For_Allocates call completes successfully, APPC/MVS begins placing inbound allocate requests that arrive for the server in an allocate queue.

   The primary parameter returned from Register_For_Allocates is the allocate queue token, which uniquely identifies the queue from which the server will select requests.

2. Serving requests —

   To obtain an allocate request from an allocate queue, a server calls the Receive_Allocate service, and supplies the allocate queue token it received at the completion of its call to the Register_For_Allocates service.

   The Receive_Allocate service returns to the server the conversation ID of the conversation just received. The server uses the conversation ID to hold APPC communications with the client TP. Both client and server can use the existing CPI-C or MVS specific conversation services described in z/OS MVS Programming: Writing Transaction Programs for APPC/MVS, such as Send_Data or Receive_and_Wait.

3. End processing —

   To stop serving allocate requests, a server calls the Unregister_For_Allocates service.