AutoLISP has several predefined variables that can be used with your custom functions and commands.
You can change the value of these variables with the setq function. However, other applications might rely on their values being consistent; therefore, it is recommended that you do not modify these variables.
The following variables are predefined for use with AutoLISP applications:
- PAUSE - Defined as a constant string of a double backslash (\\) character. This variable is used with the command function to pause for user input.
- PI - Defined as the constant p (pi). It evaluates to approximately 3.14159.
- T - Defined as the constant T. This is used as a non-nil value.
Note: Visual LISP, by default, protects these variables from redefinition. You can override this protection through the Visual LISP Symbol Service feature or by setting a Visual LISP environment option. Visual LISP is available on Windows only.