The EXCI programming interfaces

The external CICS® interface provides two forms of programming interface: the EXCI CALL interface and the EXEC CICS interface.

The EXCI CALL interface consists of six commands that you can use to:
  • Allocate and open sessions to a CICS system from non-CICS programs running under MVS™
  • Issue DPL requests on these sessions from the non-CICS programs
  • Close and deallocate the sessions on completion of the DPL requests.
The six EXCI commands are:
  • Initialize_User
  • Allocate_Pipe
  • Open_Pipe
  • DPL_Request
  • Close_Pipe
  • Deallocate_Pipe

The EXEC CICS interface provides a single, composite command, EXEC CICS LINK PROGRAM, that performs all six commands of the EXCI CALL interface in one invocation.

This command is similar but not identical to the distributed program link command of the CICS command-level application programming interface.

API restrictions for server programs
A CICS server program invoked by an external CICS interface request is restricted to the DPL subset of the CICS application programming interface. This subset (the DPL subset) of the API commands is the same as for a CICS-to-CICS server program.

See Distributed Program Link (DPL) for details of the DPL subset for server programs.