Shared libraries and Progress
Figure 8–3 shows a top-down structure diagram for a Progress 4GL application that calls shared library functions.
Note: Both Progress graphical and character applications can access DLLs in Windows.
The dotted boxes emphasize that although shared library functions are called from within an OpenEdge application, they actually reside in external shared libraries.
An OpenEdge application can access a shared library function much like an internal 4GL procedure. The client declares the function and its file using a PROCEDURE statement, defining all function parameters with DEFINE PARAMETER statements. Progress provides a special set of parameter data types to match C and Windows data types, and a set of statements and functions to build and access C structures from Progress. The client executes the shared library function exactly like a 4GL procedure, using the RUN statement.