Futurebasic/Language/Reference/kill field

Syntax
KILL FIELD handle&amp;

Description
This statement disposes of the specified handle. This means that the memory block referenced by  gets released, and the value in   is thereafter no longer a valid handle. is commonly used with handles returned by or , but it can dispose of any kind of handle. However, you should specifically NOT use it to dispose of resources, regions, window controls, and other "standard" kinds of Macintosh objects which are created and managed by the MacOS. Instead, you should use the appropriate Toolbox routine (ReleaseResource, DisposeRgn, DisposeControl, etc.) to dispose of such objects.

is similar to the Toolbox call, except that it (like the   statement) checks for   handles and sets the   variable to zero.