The linker uses object (.OBJ) files compiled from your source files. By listing source files in the project, you automatically tell the Graphical Development Environment that the corresponding .OBJ files are in the project as well. You must not list these object files; to do so will cause linking errors. However, if you want to use other .OBJ files in the project, include them in the Project list along with your source files. For information on how to use the Edit Project dialog box to list files, see Chapter 3, “Using Projects,” in the Development Environment Guide.