register_widget_control

I’m trying to write a simple widget. I have the core functionality working, but now I’m trying to add some simple used data.

The plugin fails with

Fatal error: Call to undefined function wp_register_widget_control()

Including widgets.php leads to more undefined function calls.

Searching on register_widget_control returns nothing….

Looking at other plugins, they don’t seem to do anything special….

Is there something special I need to do to enable widget control?

Or is there a detailed HOWTO on writing widget controls?

Thanks,

–Yan