API concepts

An application programming interface (API) is a functional interface supplied by the operating system or a separately orderable licensed program that allows an application program written in a high-level language to use specific data or functions of the operating system or the licensed program.

Some APIs provide the same functions as control language (CL) commands and output file support. Some APIs provide functions that CL commands do not. Most APIs work more quickly and use less system overhead than the CL commands.

API use has the following advantages:

• APIs provide better performance when getting system information or when using system functions that are provided by CL commands or output file support.
• APIs provide system information and functions that are not available through CL commands.
• You can use calls from high-level languages to APIs.
• You can access system functions at a lower level than what was initially provided on the system.
• Data is often easier to work with when returned by an API.