OTMA Callable Interface

The OTMA C/I API consists of API calls that are available to a C/C++ program. The API calls are used to join the IMS/OTMA z/OS cross-system coupling facility (XCF) group, to connect to IMS, to allocate communication sessions, to send IMS transactions/commands, to receive output from IMS, to close communication sessions, and to leave the XCF group.

The OTMA C/I API calls and sample OTMA C/I application programs are documented in IMS Version 15.2 System Programming APIs. Codes returned by the OTMA C/I are documented in IMS Version 15.2 Messages and Codes, Volume 4: IMS Component Codes

The following figure provides an overview of the OTMA C/I. Shown from left to right, in a sample z/OS environment, are sample C and C++ API calls (for example, OTMA_OPEN). The API calls pass through an object stub, the SVC interface routine, the API (for example, DFSYOPEN), and finally through the XCF group to IMS OTMA.

Figure 1. OTMA Callable Interface overview

The program that invokes the API calls can be running from an authorized or unauthorized library in problem or supervisor state. DFSYC0, a C header file, is provided to define the API calls. DFSYCRET, a load module, contains the entry points for each API call and is linked with the application program. OTMA C/I uses BPE SVC Services to process the API call.

Benefits: A key benefit of OTMA C/I is that it is easy to use.