XtClass(3)							   XT FUNCTIONS 							XtClass(3)

NAME

       XtClass, XtSuperclass, XtIsSubclass, XtCheckSubclass, XtIsObject, XtIsRectObj, XtIsWidget, XtIsComposite, XtIsConstraint, XtIsShell, XtIs-
       OverrideShell, XtIsWMShell, XtIsVendorShell, XtIsTransientShell, XtIsTopLevelShell, XtIsApplicationShell, XtIsSessionShell - obtain and
       verify a widget's class

SYNTAX

       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 XtIsSubclass to find out if a widget belongs to the desired class of
       objects.

       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 speci-
       fied 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.

       To test if a given widget belongs to a subclass of an Intrinsics-defined 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, XtIsTransientShell, XtIsTopLevelShell, XtIsApplicationShell, and XtIsSession-
       Shell.

       The

SEE ALSO

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

X Version 11							    libXt 1.1.3 							XtClass(3)