[erlang-questions] make_ref bug or feature?
Fri Mar 27 12:57:41 CET 2009
Since a reference contains a node name, it's considered unique in a
distributed setup when nodes have different names (or within a single
non-distributed node). When two shells are started this way, since they
are not aware of each other and can't see each other's references, is it
a problem that their values are identical?
Joe Armstrong wrote:
> I got a question from Ivo Danihelka about make_ref().
> Isn't make_ref() supposed to generate "an almost unique reference" the
> manual says
> "Returns an almost unique reference.
> The returned reference will re-occur after approximately 2^82
> calls; therefore it is unique enough for practical purposes."
> If I start two erlang shells and evaluate the following in both shells:
> 1> io:format("~p~n",[term_to_binary(make_ref())]).
> They *both* print the same thing - this violates the principle of
> least astonishment.
> (I thought I'd have to start 2^82 shells :-)
> Is this a bug or a feature?
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