Compile the hlprodsp.c dispatch routine source file and your C routine source files. For example, the following command compiles source files source.c and hlprodsp.c:
c source.c hlprodsp.c
The C script is in $DLC/oebuild/hlc on UNIX and %DLC%\oebuild\hlc in Windows. It contains a number of options you might want to modify for your particular application environment.