O'Reilly logo

Mastering Perl/Tk by Nancy Walsh, Stephen Lidie

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Widget Existence

To determine if a widget has been created and not destroyed, use Exists($widget):

if (Exists($widget)) {
   ...
}

Note the uppercase E on this method. The Exists method is different from the built-in Perl exists function. Make sure you don’t confuse the two.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required