XtClass(3X11)           COMMAND REFERENCE           XtClass(3X11)



NAME
     XtClass, XtSuperClass, XtIsSubclass, XtCheckSubclass,
     XtIsComposite, XtIsManaged - obtain and verify a widget's
     class

SYNOPSIS
     WidgetClass XtClass(w)
           Widget w;

     WidgetClass XtSuperclass(w)
           Widget w;

     Boolean XtIsSubclass(w, widget_class)
           Widget w;
           WidgetClass widget_class;

     void XtCheckSubclass(w, widget_class, message)
           Widget w;
           WidgetClass widget_class;
           String message;

     Boolean XtIsComposite(w)
           Widget w;

     Boolean XtIsManaged(w)
            Widget w;

     This is user-contributed.

ARGUMENTS
     w         Specifies the widget.

     widget_class
               Specifies the widget class.

     message   Specifies the message that is to be used.

DESCRIPTION
     The XtClass function returns a pointer to the widget's class
     structure.

     The XtSuperclass function returns a pointer to the widget's
     superclass class structure.

     The XtIsSubclass function returns True if the class of the
     specified widget is equal to or is a subclass of the
     specified widget class.  The specified widget can be any
     number of subclasses down the chain and need not be an
     immediate subclass of the specified widget class.  Composite
     widgets that need to restrict the class of the items they
     contain can use XtIsSubclass to find out if a widget belongs
     to the desired class of objects.



X Version 11            1 September 1988                        1

XtClass(3X11)           COMMAND REFERENCE           XtClass(3X11)



     The XtCheckSubclass macro determines if the class of the
     specified widget is equal to or is a subclass of the
     specified widget class.  The widget can be any number of
     subclasses down the chain and need not be an immediate
     subclass of the specified widget class.  If the specified
     widget is not a subclass, XtCheckSubclass constructs an
     error message from the supplied message, the widget's actual
     class, and the expected class and calls XtErrorMsg.
     XtCheckSubclass should be used at the entry point of
     exported routines to ensure that the client has passed in a
     valid widget class for the exported operation.

     XtCheckSubclass is only executed when the widget has been
     compiled with the compiler symbol DEBUG defined; otherwise,
     it is defined as the empty string and generates no code.

     The XtIsComposite function is a convenience function that is
     equivalent to XtIsSubclass with compositeWidgetClass
     specified.

     The XtIsManaged macro (for widget programmers) or function
     (for application programmers) returns True if the specified
     child widget is managed or False if it is not.

SEE ALSO
     XtAppErrorMsg(3x11), XtDisplay(3x11)
     X Toolkit Intrinsics - C Language Interface
     Xlib - C Language X Interface



























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