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XtClass(3)			 XT FUNCTIONS			    XtClass(3)

NAME
       XtClass,	XtSuperclass, XtIsSubclass, XtCheckSubclass, XtIsObject, XtIs-
       RectObj,	XtIsWidget, XtIsComposite, XtIsConstraint, XtIsShell, XtIs-
       OverrideShell, XtIsWMShell, XtIsVendorShell, XtIsTransientShell,	XtIs-
       TopLevelShell, XtIsApplicationShell, XtIsSessionShell - obtain and ver-
       ify a widget's class

SYNTAX
       #include	<X11/Intrinsic.h>

       WidgetClass XtClass(Widget w);

       WidgetClass XtSuperclass(Widget w);

       Boolean XtIsSubclass(Widget w, WidgetClass widget_class);

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

       Boolean XtIsObject(Widget w);

       Boolean XtIsRectObj(Widget w);

       Boolean XtIsWidget(Widget w);

       Boolean XtIsComposite(Widget w);

       Boolean XtIsConstraint(Widget w);

       Boolean XtIsShell(Widget	w);

       Boolean XtIsOverrideShell(Widget	w);

       Boolean XtIsWMShell(Widget w);

       Boolean XtIsVendorShell(Widget w);

       Boolean XtIsTransientShell(Widget w);

       Boolean XtIsTopLevelShell(Widget	w);

       Boolean XtIsApplicationShell(Widget w);

       Boolean XtIsSessionShell(Widget w);

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 class.  The	wid-
       get's class can be any number of	subclasses down	the chain and need not
       be an immediate subclass	of the specified class.	 Composite widgets
       that need to restrict the class of the items they contain can use XtIs-
       Subclass	to find	out if a widget	belongs	to the desired class of	ob-
       jects.

       The XtCheckSubclass macro determines if the class of the	specified wid-
       get 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 en-
       try 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.

       To test if a given widget belongs to a subclass of an Intrinsics-de-
       fined class, the	Intrinsics defines macros or functions equivalent to
       XtIsSubclass for	each of	the built-in classes.  These procedures	are
       XtIsObject, XtIsRectObj,	XtIsWidget, XtIsComposite, XtIsConstraint,
       XtIsShell, XtIsOverrideShell, XtIsWMShell, XtIsVendorShell, XtIs-
       TransientShell, XtIsTopLevelShell, XtIsApplicationShell,	and XtIsSes-
       sionShell.

       The

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

X Version 11			  libXt	1.2.1			    XtClass(3)
NAME | SYNTAX | ARGUMENTS | DESCRIPTION | SEE ALSO

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