


XtClass(3Xt)							 XtClass(3Xt)
X11R5									X11R5



NAME
  XtClass, XtSuperclass, XtIsSubclass, XtCheckSubclass,	XtIsComposite,
  XtIsManaged -	obtain and verify a widget's class

SYNTAX
  WidgetClass XtClass(_w)
	Widget _w;

  WidgetClass XtSuperclass(_w)
	Widget _w;

  Boolean XtIsSubclass(_w, _w_i_d_g_e_t__c_l_a_s_s)
	Widget _w;
	WidgetClass _w_i_d_g_e_t__c_l_a_s_s;

  void XtCheckSubclass(_w, _w_i_d_g_e_t__c_l_a_s_s,	_m_e_s_s_a_g_e)
	Widget _w;
	WidgetClass _w_i_d_g_e_t__c_l_a_s_s;
	String _m_e_s_s_a_g_e;

  Boolean XtIsComposite(_w)
	Widget _w;

  Boolean XtIsManaged(_w)
	 Widget	_w;

ARGUMENTS

  _w	    Specifies the widget.

  _w_i_d_g_e_t__c_l_a_s_s
	    Specifies the widget class.

  _m_e_s_s_a_g_e   Specifies the message that is to be	used.

DESCRIPTION
  The _X_t_C_l_a_s_s function returns a pointer to the	widget's class structure.

  The _X_t_S_u_p_e_r_c_l_a_s_s function returns a pointer to the widget's superclass
  class	structure.

  The _X_t_I_s_S_u_b_c_l_a_s_s function returns _T_r_u_e if the	class of the specified widget
  is equal to or is a subclass of the specified	widget class.  The specified
  widget can be	any number of subclasses down the chain	and need not be	an
  immediate subclass of	the specified widget class.  Composite widgets that
  need to restrict the class of	the items they contain can use _X_t_I_s_S_u_b_c_l_a_s_s
  to find out if a widget belongs to the desired class of objects.

  The _X_t_C_h_e_c_k_S_u_b_c_l_a_s_s 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, _X_t_C_h_e_c_k_S_u_b_c_l_a_s_s constructs an error	message	from the supplied
  message, the widget's	actual class, and the expected class and calls _X_t_E_r_-
  _r_o_r_M_s_g.  _X_t_C_h_e_c_k_S_u_b_c_l_a_s_s should be used at the entry point of	exported rou-
  tines	to ensure that the client has passed in	a valid	widget class for the
  exported operation.

  _X_t_C_h_e_c_k_S_u_b_c_l_a_s_s 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.

  The _X_t_I_s_C_o_m_p_o_s_i_t_e function is	a convenience function that is equivalent to
  _X_t_I_s_S_u_b_c_l_a_s_s with _c_o_m_p_o_s_i_t_e_W_i_d_g_e_t_C_l_a_s_s specified.

  The _X_t_I_s_M_a_n_a_g_e_d macro	(for widget programmers) or function (for application
  programmers) returns _T_r_u_e if the specified child widget is managed or	_F_a_l_s_e
  if it	is not.

SEE ALSO
  XtAppErrorMsg(3Xt), XtDisplay(3Xt)
  _X _T_o_o_l_k_i_t _I_n_t_r_i_n_s_i_c_s - _C _L_a_n_g_u_a_g_e _I_n_t_e_r_f_a_c_e
  _X_l_i_b - _C _L_a_n_g_u_a_g_e _X _I_n_t_e_r_f_a_c_e



















































