Progress
External Program
Interfaces


Shared Libraries and Progress

Figure 1–4 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.

Figure 1–4: Progress Application Calling DLL Functions

The dotted boxes emphasize that although shared library functions are called from within a Progress application, they actually reside in external shared libraries.

A Progress 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.


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