Release 10.1A: OpenEdge Development:
Programming Interfaces

Shared Library and DLL Support

A shared library is a file that contains a collection of compiled functions (routines) that can be accessed by applications. Such a file is called a shared object or shared library on UNIX and a dynamic link library (DLL) in Windows.

An application links to these routines at runtime rather than at build time, and shares the code with other applications that link to them. Thus, shared libraries promote code reuse (because an application can reference third-party routines) and upgradeability (because any enhancement to a shared library becomes immediately available to your application, without rebuilding).

Progress lets you link and execute shared library routines from a 4GL procedure. Using these routines, you can write OpenEdge applications that perform a wide range of third-party functions from graphics to advanced multi-media (sound and video) production.

For more information on shared library concepts and facilities, see the documentation for your operating system.

The following sections describe how to use shared libraries in your OpenEdge applications:

Using shared libraries
Declaring a shared library routine
Executing a shared library routine
Using structure parameters
Using MEMPTR variables as parameters
DLL routines and Progress widgets (Windows only)
Loading and unloading shared libraries
Examples