2012

Table Of Contents
of the onfailure argument. In the preceding example, the value returned by
the load function is passed to the princ function, causing that value to be
displayed at the command prompt.
For example, if an error occurs while AutoCAD loads the mydocapp1.lsp file,
the princ function displays the following message and AutoCAD continues
to load the two remaining files:
MYDOCAPP1.LSP file not loaded.
If you use the command function in an acad.lsp, acaddoc.lsp, or MNL file, it
should be called only from within a defun statement. Use the S::STARTUP
function to define commands that need to be issued immediately when you
begin a drawing session.
S::STARTUP Function: Postinitialization Execution
You can define an S::STARTUP function to perform any needed setup
operations after the drawing is initialized.
The startup LISP files (acad.lsp, acaddoc.lsp, and MNL) are all loaded into
memory before the drawing is completely initialized. Typically, this does not
pose a problem, unless you want to use the command function, which is not
guaranteed to work until after a drawing is initialized.
If the user-defined function S::STARTUP is included in an acad.lsp, acaddoc.lsp,
or MNL file, it is called when you enter a new drawing or open an existing
drawing. Thus, you can include a definition of S::STARTUP in the AutoLISP
startup file to perform any setup operations.
442 | Chapter 7 Introduction to Programming Interfaces