NAME

       XtAddGrab, XtRemoveGrab - redirect user input to a modal widget

SYNTAX

       #include <X11/Intrinsic.h>

       void XtAddGrab(Widget w, Boolean exclusive, Boolean spring_loaded);

       void XtRemoveGrab(Widget w);

ARGUMENTS

       exclusive Specifies  whether  user  events  should  be  dispatched  exclusively to this widget or also to
                 previous widgets in the cascade.

       spring_loaded
                 Specifies whether this widget was popped up because the user pressed a pointer button.

       w         Specifies the widget to add to or remove from the modal cascade.

DESCRIPTION

       The XtAddGrab function appends the widget (and associated parameters) to the  modal  cascade  and  checks
       that exclusive is True if spring_loaded is True.  If these are not True, XtAddGrab generates an error.

       The  modal  cascade is used by XtDispatchEvent when it tries to dispatch a user event.  When at least one
       modal widget is in the widget cascade, XtDispatchEvent first determines if the event should be delivered.
       It starts at the most recent cascade entry and follows the cascade up to and including  the  most  recent
       cascade entry added with the exclusive parameter True.

       This  subset of the modal cascade along with all descendants of these widgets comprise the active subset.
       User events that occur outside the widgets in this subset are ignored  or  remapped.   Modal  menus  with
       submenus  generally  add  a  submenu widget to the cascade with exclusive False.  Modal dialog boxes that
       need to restrict user input to the most deeply nested dialog box add a subdialog widget  to  the  cascade
       with  exclusive  True.   User events that occur within the active subset are delivered to the appropriate
       widget, which is usually a child or further descendant of the modal widget.

       Regardless of where on the screen they occur, remap events are always delivered to the most recent widget
       in the active subset of the cascade that has spring_loaded True, if any such widget exists.

       The XtRemoveGrab function removes widgets from the modal cascade starting at the most recent widget up to
       and including the specified widget.  It issues an error if the specified  widget  is  not  on  the  modal
       cascade.

SEE ALSO

       X Toolkit Intrinsics - C Language Interface
       Xlib - C Language X Interface

X Version 11                                       libXt 1.2.1                                      XtAddGrab(3)