Whenever a check box is clicked by the user, the check box’s value is toggled and its callback procedure is invoked. A callback procedure is provided as an initialization argument when each check box is created.

If & occurs in label (when label is a string), it is specially parsed as for button%.

The callback procedure is called (with the event type 'check-box) whenever the user clicks the check box.

If style includes 'deleted, then the check box is created as hidden, and it does not affect its parent’s geometry; the check box can be made active later by calling parent’s add-child method.

If value is true, it is passed to set-value so that the box is initially checked.

The font argument determines the font for the control. For information about the enabled argument, see window<%>. For information about the horiz-margin and vert-margin arguments, see subarea<%>. For information about the min-width, min-height, stretchable-width, and stretchable-height arguments, see area<%>.

Otherwise, sets the bitmap label for a bitmap check box. Since label is a bitmap, the bitmap must be valid (see ok? in bitmap%) and not installed in a bitmap-dc% object; otherwise, an exn:fail:contract exception is raised. If the bitmap has a mask (see get-loaded-mask in bitmap%) that is the same size as the bitmap, then the mask is used for the label; furthermore, in contrast to the limitations of draw-bitmap in dc<%>, non-monochrome label masks work consistently on all platforms. The bitmap label is installed only if the control was originally created with a bitmap label.

The check box’s state can be changed by the user clicking the control, and such changes do not go through this method; use the control callback procedure (provided as an initialization argument) to monitor state changes.