Using Allocate Queue Services

Objective

This chapter provides the conceptual information you need to use APPC/MVS allocate queue callable services.

For specific information about coding the parameters on these services, see APPC/MVS Allocate Queue Services.

In the discussion that follows, the APPC/MVS allocate queue callable services are organized, based on complexity, into two groups: basic and advanced.

The basic functions allow MVS applications to serve inbound allocate requests. These functions are used to create, serve, and delete allocate queues. The allocate queue services that provide the basic functions are:

Register_For_Allocates (ATBRFA2) — Register for inbound allocate requests.
Receive_Allocate (ATBRAL2) — Request an inbound conversation for processing.
Unregister_For_Allocates (ATBURA2) — Unregister for inbound allocate requests.

These services are described in The Basic Server Functions.

APPC/MVS servers use the advanced functions to manage the allocate queues for which the servers are registered. Servers could, for example, use advanced functions to aid in performing load balancing. The allocate queue services that provide the advanced functions are:

Set_Allocate_Queue_Notification (ATBSAN2) — Request to be notified when an allocate queue reaches a specified maximum or minimum number of allocate requests (or cancel a previous request for such notification).
Get_Event (ATBGTE2) — Obtain notification of events that was previously requested through the Set_Allocate_Queue_Notification service.
Query_Allocate_Queue (ATBQAQ2) — Obtain commonly needed information about the status of an allocate queue, such as the number of allocate requests that currently reside on the queue.
Set_Allocate_Queue_Attributes (ATBSAQ2) — Have APPC/MVS preserve a particular allocate queue during periods of time when no servers are registered for the queue.

These services are described in Advanced Server Functions.

Coded Example
This book concludes with a coded example of an APPC client/server application (written in the C programming language), in three parts: Sample APPC/MVS Server Sample Client Program Sample Error Routine and Header File.