NAME

       XtClass, XtSuperclass, XtIsSubclass, XtCheckSubclass, XtIsObject, XtIsRectObj, XtIsWidget, XtIsComposite,
       XtIsConstraint,   XtIsShell,   XtIsOverrideShell,   XtIsWMShell,   XtIsVendorShell,   XtIsTransientShell,
       XtIsTopLevelShell, XtIsApplicationShell, XtIsSessionShell - obtain and verify 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 widget'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  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.

       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
       XtIsSessionShell.

       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)