(Api, or "application programming interface") The interface (calling conventions) by which an {application program} accesses {operating system} and other services. An Api is defined at source code level and provides a level of abstraction between the application and the kernel (or other privileged utilities) to ensure the portability of the code. An Api can also provide an interface between a {high level language} and lower level utilities and services which were written without consideration for the calling conventions supported by compiled languages. In this case, the Api' s main task may be the translation of parameter lists from one format to another and the interpretation of call-by-value and call-by-reference arguments in one or both directions. (1995-02-15)