XtCreateWidget(3Xt) AIX (XT FUNCTIONS) XtCreateWidget(3Xt) NAME XtCreateWidget, XtCreateManagedWidget, XtDestroyWidget - create and destroy widgets SYNTAX Widget XtCreateWidget(_n_a_m_e, _w_i_d_g_e_t__c_l_a_s_s, _p_a_r_e_n_t, _a_r_g_s, _n_u_m__a_r_g_s) String _n_a_m_e; WidgetClass _w_i_d_g_e_t__c_l_a_s_s; Widget _p_a_r_e_n_t; ArgList _a_r_g_s; Cardinal _n_u_m__a_r_g_s; Widget XtCreateManagedWidget(_n_a_m_e, _w_i_d_g_e_t__c_l_a_s_s, _p_a_r_e_n_t, _a_r_g_s, _n_u_m__a_r_g_s) String _n_a_m_e; WidgetClass _w_i_d_g_e_t__c_l_a_s_s; Widget _p_a_r_e_n_t; ArgList _a_r_g_s; Cardinal _n_u_m__a_r_g_s; void XtDestroyWidget(_w) Widget _w; ARGUMENTS _a_r_g_s Specifies the argument list to override the resource defaults. _n_a_m_e Specifies the resource name for the created wid- get, which is used for retrieving resources and, for that reason, should not be the same as any other widget that is a child of same parent. _n_u_m__a_r_g_s Specifies the number of arguments in the argument list. _p_a_r_e_n_t Specifies the parent widget. _w Specifies the widget. _w_i_d_g_e_t__c_l_a_s_s Specifies the widget class pointer for the created widget. DESCRIPTION The _X_t_C_r_e_a_t_e_W_i_d_g_e_t function performs much of the boilerplate operations of widget creation: o+ Checks to see if the class_initialize procedure has been called for this class and for all superclasses and, if not, calls those necessary in a superclass-to- subclass order. Rev. Release 3 Page 1 XtCreateWidget(3Xt) AIX (XT FUNCTIONS) XtCreateWidget(3Xt) o+ Allocates memory for the widget instance. o+ If the 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, it allocates memory for the parent's constraints and stores the address of this memory into the constraints field. o+ Initializes the core nonresource data fields (for exam- ple, parent and visible). o+ Initializes the resource fields (for example, background_pixel) by using the resource lists specified for this class and all superclasses. o+ If the 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, it initializes the resource fields of the constraints record by using the constraint resource list specified for the parent's class and all superclasses up to _c_o_n_- _s_t_r_a_i_n_t_W_i_d_g_e_t_C_l_a_s_s. o+ Calls the initialize procedures for the widget by starting at the _C_o_r_e initialize procedure on down to the widget's initialize procedure. o+ If the parent is a subclass of _c_o_m_p_o_s_i_t_e_W_i_d_g_e_t_C_l_a_s_s, it puts the widget into its parent's children list by cal- ling its parent's insert_child procedure. For further information, see Section 3.5. o+ If the 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, it calls the constraint initialize procedures, starting at _c_o_n_s_t_r_a_i_n_t_W_i_d_g_e_t_C_l_a_s_s on down to the parent's con- straint initialize procedure. Note that you can determine the number of arguments in an argument list by using the _X_t_N_u_m_b_e_r macro. For further information, see Section 11.1. The _X_t_C_r_e_a_t_e_M_a_n_a_g_e_d_W_i_d_g_e_t function is a convenience routine that calls _X_t_C_r_e_a_t_e_W_i_d_g_e_t and _X_t_M_a_n_a_g_e_C_h_i_l_d. The _X_t_D_e_s_t_r_o_y_W_i_d_g_e_t function provides the only method of destroying a widget, including widgets that need to destroy themselves. It can be called at any time, including from an application callback routine of the widget being destroyed. This requires a two-phase destroy process in order to avoid dangling references to destroyed widgets. In phase one, _X_t_D_e_s_t_r_o_y_W_i_d_g_e_t performs the following: o+ If the being_destroyed field of the widget is _T_r_u_e, it returns immediately. Rev. Release 3 Page 2 XtCreateWidget(3Xt) AIX (XT FUNCTIONS) XtCreateWidget(3Xt) o+ Recursively descends the widget tree and sets the being_destroyed field to _T_r_u_e for the widget and all children. o+ Adds the widget to a list of widgets (the destroy list) that should be destroyed when it is safe to do so. Entries on the destroy list satisfy the invariant that if w2 occurs after w1 on the destroy list then w2 is not a descen- dent of w1. (A descendant refers to both normal and pop-up children.) Phase two occurs when all procedures that should execute as a result of the current event have been called (including all procedures registered with the event and translation managers), that is, when the current invocation of _X_t_D_i_s_p_a_t_c_h_E_v_e_n_t is about to return or immediately if not in _X_t_D_i_s_p_a_t_c_h_E_v_e_n_t. In phase two, _X_t_D_e_s_t_r_o_y_W_i_d_g_e_t performs the following on each entry in the destroy list: o+ Calls the destroy callback procedures registered on the widget (and all descendants) in post-order (it calls children callbacks before parent callbacks). o+ If the widget's parent is a subclass of _c_o_m_p_o_s_i_- _t_e_W_i_d_g_e_t_C_l_a_s_s and if the parent is not being destroyed, it calls _X_t_U_n_m_a_n_a_g_e_C_h_i_l_d on the widget and then calls the widget's parent's delete_child procedure (see Sec- tion 3.4). o+ 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, it calls the constraint destroy procedure for the parent, then the parent's superclass, until finally it calls the constraint destroy procedure for _c_o_n_s_t_r_a_i_n_t_W_i_d_g_e_t_C_l_a_s_s. o+ Calls the destroy methods for the widget (and all des- cendants) in post-order. For each such widget, it calls the destroy procedure declared in the widget class, then the destroy procedure declared in its superclass, until finally it calls the destroy pro- cedure declared in the Core class record. o+ Calls _X_D_e_s_t_r_o_y_W_i_n_d_o_w if the widget is realized (that is, has an X window). The server recursively destroys all descendant windows. o+ Recursively descends the tree and deallocates all pop- up widgets, constraint records, callback lists and, if the widget is a subclass of _c_o_m_p_o_s_i_t_e_W_i_d_g_e_t_C_l_a_s_s, chil- dren. Rev. Release 3 Page 3 XtCreateWidget(3Xt) AIX (XT FUNCTIONS) XtCreateWidget(3Xt) SEE ALSO XtAppCreateShell(3Xt), XtCreatePopupShell(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 Rev. Release 3 Page 4