The 'handle' property

Read-Only (except for Socket), Integer Scalar

Valid for: Check, Radio, Button, Progress, Trackbar, Spinner, Scroll, List, Combo, Edit, RichEdit, Movie, Splitter, Selector, Page, Tree, Frame, Printer, Image, ImageList, Socket

The handle property is generally used for low-level programming only. Its value is the internal value which identifies the underlying control to the operating system.

It can be passed to external calls which require a handle argument via ⎕NA or Auxiliary Processors. If no valid handle is available (for example, if the object is not open), 0 is returned.

For a Socket object, the handle property is used in a special way for server sockets accepting requests for connection from clients. See the documentation on the Socket object for details.