Before you can define a new external function, the library containing your library file must already exist.
You can use the same library for both external functions and external methods, if required. For details about adding a library, see "Maintaining Libraries for External Methods and Functions", later in this chapter.
For details about maintaining external functions, see the following subsections.
Modifying the External Function Template
Compiling Your External Function
Example of Definition of an External Function
Example of Usage of an External Function