gtkCheckInherits            package:RGtk            R Documentation

_V_e_r_i_f_y _a_n _o_b_j_e_c_t'_s _c_l_a_s_s

_D_e_s_c_r_i_p_t_i_o_n:

     Checks whether the given object extends the appropriate class,
     raising an error if not. This is used to validate an object before
     it is passed to C code which expects an object of the appropriate
     type.

_U_s_a_g_e:

     gtkCheckInherits(w, klass="GtkWidget", nullOk=FALSE, critical=TRUE)

_A_r_g_u_m_e_n_t_s:

       w: the object whose classes are to be checked to determine if it
          ``extends'' the class 'klass'.

   klass: the class which the object 'w' is expected to extend.

  nullOk: a logical value which controls whether a value of 'NULL' for
          'w' is acceptable and passes the test. If this is not 'TRUE',
          a value of 'NULL' throws an error.

critical: a logical value or a string that controls whether an error is
          raised if the object 'w' does not inherit from 'klass'. If
          this is a string, it is used as the error message. If it is a
          logical value and is 'TRUE', an error is raised. 

_D_e_t_a_i_l_s:

     This

_V_a_l_u_e:

     A logical value or an error!

_A_u_t_h_o_r(_s):

     Duncan Temple Lang <duncan@research.bell-labs.com>

_R_e_f_e_r_e_n_c_e_s:

_S_e_e _A_l_s_o:

     'inherits' 'stop'

_E_x_a_m_p_l_e_s:

