This is macro LE_RECTANGLEWIDGET_VTABLE.

#define LE_RECTANGLEWIDGET_VTABLE(THIS_TYPE) \
    LE_WIDGET_VTABLE(THIS_TYPE) \
    \
    int32_t   (*getThickness)(const THIS_TYPE* _this); \
    leResult  (*setThickness)(THIS_TYPE* _this, int32_t thk); \