Requirements for application programs

As described in previous sections, VTAM® CMIP services provides many services that free application programs from having to code many of the common CMIP functions. The application program is therefore allowed to focus on functions specific to the object instances it represents. The application program implements the behavior of its objects. It must:

Code an APPL definition statement to define the application program to VTAM. See z/OS Communications Server: SNA Resource Definition Reference for information about the APPL definition statement.
Connect to VTAM CMIP services using the MIBConnect function. When using the MIBConnect function, the application program must provide the address of its read queue exit routine. The read queue exit routine is required for application programs to communicate with CMIP services.
It is highly recommended that you code a TPEND exit routine for VTAM to invoke when VTAM is terminating. If you code a TPEND exit routine, you must provide its address.
Register at least one object instance using the MIBSendRegister function. An application program can register as many object instances as it represents. An object instance cannot be registered by more than one application program.
Implement the behavior of the object instances it represents. CMIP services does not provide a repository for object attributes. Any CMIP operations targeting an object instance are delivered to the application program that registered that instance (or, in the case of a subtree manager, the application program that registered the subtree containing that instance).
For example, a CMIP GET request is forwarded to the application program representing the objects targeted in the request. Those application programs are responsible for collecting the requested attributes, building them into the proper response, and sending them using the MIBSendCmipResponse function.

For scoped requests that affect object instances across multiple application programs, no coordination is needed between the application programs. CMIP services coordinates the requests for the application program. Your application program simply indicates that it has finished its part of the response by setting the last-in-chain attribute when invoking the MIBSendCmipResponse function. For hints on coding subtree managers see Subtree managers. An application program can be both a manager and an agent, but it is helpful to separate them for the following discussion under Types of application programs.
Issue the MIBDisconnect function to disconnect the application from CMIP services.