XtClass(3Xt) XT FUNCTIONS XtClass(3Xt)
NAME
XtClass, XtSuperclass, XtIsSubclass, XtCheckSubclass, XtIs-
Object, XtIsRectObj, XtIsWidget, XtIsComposite, XtIs-
Constraint, XtIsShell, XtIsOverrideShell, XtIsWMShell, XtIs-
VendorShell, XtIsTransientShell, XtIsTopLevelShell, XtIs-
ApplicationShell, 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.
XFree86 Version 4.5.0 1
XtClass(3Xt) XT FUNCTIONS XtClass(3Xt)
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 speci-
fied class. The widget's class can be any number of subc-
lasses down the chain and need not be an immediate subclass
of the specified class. Composite widgets that need to res-
trict the class of the items they contain can use XtIsSub-
class 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 speci-
fied widget class. The widget can be any number of subc-
lasses 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, XtIs-
OverrideShell, XtIsWMShell, XtIsVendorShell, XtIsTransient-
Shell, XtIsTopLevelShell, XtIsApplicationShell, and ZN
XtIsSessionShell .
The
SEE ALSO
XtAppErrorMsg(3Xt), XtDisplay(3Xt)
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface
XFree86 Version 4.5.0 2