Displays a dialog box containing an error or warning message
(alert string)
Display a message in an alert box:
(alert "That function is not available.")
Display a multiple line message, by using the newline character in string:
(alert "That function\nis not available.")
NoteLine length and the number
of lines in an alert box are platform, device, and window dependent. AutoCAD truncates
any string that is too long to fit inside an alert box.