XtClass(3) XT FUNCTIONS XtClass(3)

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

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 1.1.5 XtClass(3)