Global libinput_unref (struct libinput *libinput): When the refcount reaches zero, libinput_unref() releases resources even if a caller still holds refcounted references to related resources (e.g. a libinput_device). When libinput_unref() returns NULL, the caller must consider any resources related to that context invalid. See https://bugs.freedesktop.org/show_bug.cgi?id=91872.