Program linkage

A program system consists of a main program (the program that is called at system level) and one or more external subprograms, which may be written in the same language as the main program or in other programming languages.

Consequently, a means of linking the various programs is required; this function is performed by the Inter-Language Communication Services (ILCS). ILCS is a component of the Common Runtime Environment (CRTE) and is described in the “CRTE User Guide” [2].