To Monitor Variables during Program Execution with the Watch Window (Visual LISP IDE)

Viewing the value of a variable at run-time can be useful in debugging an issue with a program.

Note: The Visual LISP IDE is available on Windows only.

When not using Visual LISP, you can use the princ function to display the current value of a variable during the execution of a program.

Display the Watch window

• In Visual LISP, click View Watch Window.

Add a variable to the Watch window

1. In Visual LISP, text editor window, double-click or select a variable name.
2. Right-click and click Add Watch.

   Visual LISP passes the variable’s name to the Watch window and displays its current value.

   
   Note: If the Watch window is not already open and you want to view a variable's value, you can open the window by clicking View Watch Window from the Visual LISP menu bar.

   If you click the Add Watch button from the Watch window without selecting a variable name from the text editor window first, the following window appears:

   

Remove a variable from the Watch window

1. In the Watch window, select the variable to remove and right-click.

   If the Watch window is not displayed, click View Watch Window.

2. Click Remove from Watch.

View the return value of the last evaluated expression

• In Visual LISP, click Debug Watch Last Evaluation.
  

  Visual LISP displays the Watch window, which shows the value of the *LAST-VALUE* IDE global variable. Visual LISP always stores the value of the last evaluated expression in the *LAST-VALUE* variable.