Release 10.1A: OpenEdge Development:
Programming Interfaces

Overview of HLC

You can use HLC to add virtually any feature to Progress that is written in C and that follows HLC programming rules. To use HLC, you should be familiar with the following topics:

Using the Progress 4GL client.
Using the OEBuild utility. For more information on the OEBuild Utility, see Building OpenEdge 4GL Executables at www.progress.com/products/documentation/start_openedge10/index.ssp.
Designing, compiling, and linking C programs. See the C documentation for more information.

Figure 18–2 illustrates the steps to build an HLC executable.

Figure 18–2: Steps to build an HLC executable

To build an HLC executable:

Write your C functions and update the PRODSP() dispatch routine contained in hlprodsp.c.
Compile your C routine source files and the hlprodsp.c dispatch routine source file.
Use the OEBuild utility to generate a link script for your executable.
Link your C object files, the hlprodsp.c dispatch routine object file, and Progress object files, using the link script that OEBuild generates.

For more information on the OEBuild utility, see Building OpenEdge 4GL Executables at www.progress.com/products/documentation/start_openedge10/index.ssp.

To use HLC you must build an HLC executable. An HLC executable is a Progress module with your C functions linked. Once you build an HLC executable, you can use the CALL statement to execute a linked C function from a Progress 4GL procedure.