CPI-C Reference

Identifying the Partner Program

CPI Communications requires a certain amount of destination information, such as the name of the partner program and the name of the CRM at the partner's node, before it can establish a conversation. Sources for this information include:

• Program-supplied
  The program can supply the destination information directly.

• Side information
  The program can use data contained in local side information. The side information is accessed using an 8-byte symbolic destination name or sym_dest_name, which identifies the partner program.

• Distributed directory
  The program can use a directory object contained in a distributed directory. The directory object represents a particular installation of a program and is identified by a variable-length distinguished name (DN). Programs not having a DN for their partner program can search the directory for objects containing a program function identifier (PFID). The PFID is a globally-unique identifier for the function provided by the program.

There are some considerations to keep in mind when using the different techniques:

• Program-supplied information may require recompilation if the address of the partner program changes.

• Use of sym_dest_name allows only a small name space of locally-defined names.

• Side information requires local administration on each system.

• Movement of a program may result in update of side information on multiple systems.

• Use of a distributed directory enables destination information to be stored in a single location and accessed by multiple programs.

• As with the sym_dest_name, a DN identifies a particular installation of a program and destination information may not be known at program development time. For example, shrink-wrapped programs will not have access to the DN when distributed. Use of the PFID solves this problem by allowing a run-time search of the directory for all program installation objects with a particular functionality.

• "Side Information" and "Distributed Directory" discuss how existing CPI Communications programs using side information can be migrated to use the distributed directory by using the sym_dest_name to identify a side-information entry containing a DN.