Function gtk_sys::gtk_menu_popup_at_rect

pub unsafe extern "C" fn gtk_menu_popup_at_rect(
    menu: *mut GtkMenu,
    rect_window: *mut GdkWindow,
    rect: *const GdkRectangle,
    rect_anchor: GdkGravity,
    menu_anchor: GdkGravity,
    trigger_event: *const GdkEvent
)