About This Manual

The External Development Guide describes options for using code not written in the IDL language alongside IDL itself. It is divided into three parts:

Part I: Techniques That Do Not Use IDL's Internal API

This section discusses techniques that allow IDL to work together with programs written in other programming languages, using IDL's "public" interfaces. Little or no familiarity with IDL's internal interfaces is required. For many users, the techniques in this section will solve most problems that require IDL to use — or be used by — other programs. Topics covered in Part I include:

Letting IDL programs interact with other programs via pipes.

Incorporating COM objects and ActiveX controls into IDL programs.

Incorporating Java objects into IDL programs.

Using IDL as a Remote Procedure Call server on a UNIX system.

Calling routines written in other programming languages from within IDL using the CALL_EXTERNAL function.

Part II: IDL's Internal API

This section describes IDL's internal implementation in enough detail to allow you to write an IDL system routine in another compiled programming language (usually C) and link it with IDL.

Part III: Techniques That Use IDL's Internal API

This section describes the process of combining IDL with code written in another programming language. Topics covered in Part III include:

Creating a system routine using the interface described in Part II and linking that routine into IDL at runtime.

Calling IDL as a subroutine from another program ("Callable IDL").

Adding user-defined widgets to IDL widget applications.