SAP ABAP How to get global variables / objects

FM WB_TREE_GET_OBJECTS is getting all global variables and objects of a program.

This sample code is getting all class alv objects from global data and clear them.

FORM free_other_alvs USING po_alv_grid TYPE REF TO cl_gui_alv_grid.


  FIELD-SYMBOLS: <fs_alv> TYPE REF TO cl_gui_alv_grid.
  DATA : lt_obj_list TYPE TABLE OF scompo,
         lv_obj_name TYPE string.


  CALL FUNCTION 'WB_TREE_GET_OBJECTS'
    EXPORTING
      program = sy-repid
    TABLES
      olist   = lt_obj_list.

  LOOP AT lt_obj_list REFERENCE INTO DATA(lr_obj_list) 
                      WHERE name+0(7) = 'GO_ALV_'.
    lv_obj_name = lr_obj_list->name.
    ASSIGN (lv_obj_name) TO <fs_alv>.
    IF <fs_alv> IS ASSIGNED.
      IF <fs_alv> = po_alv_grid.
        CONTINUE.
      ELSE.
        IF <fs_alv> IS NOT INITIAL.
          <fs_alv>->free( ).
          CLEAR <fs_alv>.
        ENDIF.
      ENDIF.
    ENDIF.
  ENDLOOP.
*

ENDFORM.