Loading Extended AutoLISP Functions

VLISP provides some extensions to the AutoLISP language that are not loaded automatically when you start AutoCAD. These functions have names that begin with vla-, vlax-, and vlr-. The vla- functions implement AutoLISP ActiveX. support. The vlax- functions provide ActiveX utility and data conversion functions, dictionary handling functions, and curve measurement functions. The vlr- functions provide support for AutoCAD reactors. Before you can use any of these functions, you must load the AutoLISP extensions with the following function call:


This function first checks if the AutoLISP extensions are already loaded; if so, the function does nothing, otherwise it loads the extensions.

AutoLISP code that includes calls to vla-, vlax-, or vlr- functions should always begin with a call to vl-load-com to ensure that the code will run; it should not be left up to the user to load the extensions. If your application does not call vl-load-com, the application may fail.