If the widget's parent is a subclass of _c_o_n_s_t_r_a_i_n_t_W_i_d_g_e_t_C_l_a_s_s, _X_t_S_e_t_V_a_l_u_e_s also updates the widget's constraints. It starts with the constraint resources specified for _c_o_n_s_t_r_a_i_n_t_W_i_d_g_e_t_C_l_a_s_s and proceeds down the subclass chain to the parent's class. At each stage, it writes the new value or the existing value to a new constraint record. It then calls the constraint set_values procedures from _c_o_n_s_t_r_a_i_n_t_W_i_d_g_e_t_C_l_a_s_s down to the parent's class. The constraint set_values procedures are called with widget arguments, as for all set_values procedures, not just the constraint record arguments, so that they can make adjustments to the desired values based on full information about the widget.
_X_t_S_e_t_V_a_l_u_e_s determines if a geometry request is needed by comparing the current widget to the new widget. If any geometry changes are required, it makes the request, and the geometry manager returns _X_t_G_e_o_m_e_t_r_y_Y_e_s, _X_t_G_e_o_m_e_t_r_y_A_l_m_o_s_t, or _X_t_G_e_o_m_e_t_r_y_N_o. If _X_t_G_e_o_m_e_t_r_y_Y_e_s, _X_t_S_e_t_V_a_l_u_e_s calls the widget's resize procedure. If _X_t_G_e_o_m_e_t_r_y_N_o, _X_t_S_e_t_V_a_l_u_e_s resets the geometry fields to their original values. If _X_t_G_e_o_m_e_t_r_y_A_l_m_o_s_t, _X_t_S_e_t_V_a_l_u_e_s calls the set_values_almost procedure, which determines what should be done and writes new values for the geometry fields into the new widget. _X_t_S_e_t_V_a_l_u_e_s then repeats this process, deciding once more whether the geometry manager should be called.
Finally, if any of the set_values procedures returned _T_r_u_e, _X_t_S_e_t_V_a_l_u_e_s causes the widget's expose procedure to be invoked by calling the Xlib _X_C_l_e_a_r_A_r_e_a function on the widget's window.
The _X_t_S_e_t_S_u_b_v_a_l_u_e_s function stores resources into the structure identified by base.
The _X_t_G_e_t_V_a_l_u_e_s function starts with the resources specified for the core widget fields and proceeds down the subclass chain to the widget. The value field of a passed argument list should contain the address into which to store the corresponding resource value. It is the caller's responsibility to allocate and deallocate this storage according to the size of the resource representation type used within the widget.
If the widget's parent is a subclass of _c_o_n_s_t_r_a_i_n_t_W_i_d_g_e_t_C_l_a_s_s, _X_t_G_e_t_V_a_l_u_e_s then fetches the values for any constraint resources requested. It starts with the constraint resources specified for _c_o_n_s_t_r_a_i_n_t_W_i_d_g_e_t_C_l_a_s_s and proceeds down to the subclass chain to the parent's constraint resources. If the argument list contains a resource name that is not found in any of the resource lists searched, the value at the corresponding address is not modified. Finally, if the get_values_hook procedures are non-NULL, they are called in superclass-to-subclass order after all the resource values have been fetched by _X_t_G_e_t_V_a_l_u_e_s. This permits a subclass to provide nonwidget resource data to _X_t_G_e_t_V_a_l_u_e_s.
The _X_t_G_e_t_S_u_b_v_a_l_u_e_s function obtains resource values from the structure identified by base.