Compiling User-Defined Function Definitions

If an explicit prototype is not specified, the characteristics of a user-defined function are extracted to internal data areas. The data extracted is analogous to an implicit prototype, with characteristics such as the function name, returning item data description, and parameter item data description extracted.

If a function is invoked in a subsequent compilation unit, that has the same function name, a conformance check is carried out, where the Compiler determines if the provided invocation context, arguments, and returning item are appropriate.