The base.dcl and acad.dcl (or acadlt.dcl for AutoCAD LT) files contain the predefined tiles and DCL dialog boxes.
These files are included with the program and are distributed in the User Support folder. To see the path to the User Support folder, use the AutoCAD ACADPREFIX system variable.
The base.dcl file shows the DCL definitions for the basic, predefined tiles and tile types. It also contains definitions for commonly used prototypes. The PDB feature does not allow you to redefine the predefined tiles. The acad.dcl (or acadlt.dcl for AutoCAD LT) file contains some standard dialog box definitions.
Caution: Any errors in
base.dcl may disrupt the appearance of the standard dialog boxes and customized dialog boxes from your application or other applications.