CICS services for application programs

The CICS application programming interface (API) provides access to a rich set of CICS services that you can use to construct sophisticated applications that consist of many interacting programs.

CICS programs that use the CICS API can perform the following operations:
  • Access data held in VSAM and BDAM data sets and in DB2 and IMS databases.
  • Communicate with a variety of terminals and devices, including printers, in your communication network.
  • Connect to programs on other platforms that use SNA and TCP/IP protocols.
  • Interact with HTTP clients and servers.
  • Operate as a web service requester or provider.
  • Exchange data with other programs in the same transaction and with other transactions.

CICS programs can manage their own storage to provide intermediate work areas and other main storage needed to process a transaction; they can handle exceptional conditions and failures; and they can capture data to help you diagnose problems.

CICS programs run as part of a transaction under the control of a CICS task and can perform the following actions:
  • Obtain information about the program's environment.
  • Initiate other transactions immediately or in the future.
  • Commit or roll back the current unit of work.
  • Reserve and relinquish locks on resources that are shared with other tasks.
  • Adjust the priority of the task, and relinquish control in favor of other tasks that have a higher priority.
  • Identify and authenticate users that initiate transactions using the services of the external security manager.
  • Capture data in journals that can be used to reconstruct events or data changes.
  • Interact with the operating system, including the system console and the JES spool.