.. hook:: H_CLONE_UIDS

  :arg closure value: mixed <closure>(object blueprint, string objectname)

  Mandatory hooks to determine the uid and euid of cloned objects. Hook settings can be any closure.

  When an object is cloned, the :hook:`H_CLONE_UIDS` hook is called with the blueprint object as the first argument and the clone's designated name as the second. The new object already exists, but has 0 uids.

  .. todo:: better markup for the literal blocks in this section

  For the result, the following possibilities exist (<num> is a non-zero number, <no-string> is anything but a string)::

    "<uid>"                    -> uid = "<uid>", euid = "<uid>"
    ({ "<uid>", "<euid>" })    -> uid = "<uid>", euid = "<euid>"
    ({ "<uid>", <no-string> }) -> uid = "<uid>", euid = 0

  If strict-euids is not active, the following results are possible, too::

    <num>                      -> uid = 0, euid = 0
    ({ <num>, "<euid>" })      -> uid = 0, euid = "<euid>"
    ({ <num>, <no-string> })   -> uid = 0, euid = 0

  .. history

  .. seealso:: :overview:`hook`, :concept:`uids`, :hook:`load_uids`