Foreign functions are subprograms written in a 3GL programming language for customizing Oracle Forms applications. Foreign functions can interact with Oracle databases, and Oracle Forms variables and items. Although it is possible to access Oracle Forms variables and items, you cannot call Oracle Forms Built-in subprograms from a foreign function.
Foreign functions can be used to perform the following tasks:
Note: You should not perform host language screen I/O from a foreign function. This restriction exists because the runtime routines that a host language uses to perform screen I/O conflict with the routines that Oracle Forms uses to perform screen I/O. However, you can perform host language file I/O from a foreign function.
Foreign functions that can be invoked from a PL/SQL interface must be contained in a dynamic library.
Initializing a foreign function identifies the location of a dynamic library and dissects the foreign function prototype. The initialization process provides a one-to-one match between foreign function host language data types and PL/SQL data types. Initialize a foreign function in a PL/SQL package body.
Creating a PL/SQL interface to foreign functions
Invoking a foreign function from a PL/SQL interface