[erlang-bugs] bug in erlang:size

Robert Virding <>
Sat Aug 4 14:16:26 CEST 2012


----- Original Message -----
> On 08/03/2012 11:12 AM, Joe Armstrong wrote:
> > I think this is a bug:
> >
> > $erl
> > 1>  B =<<1:17>>.
> > <<0,0,1:1>>
> > 2>  size(B).
> > 2
> >
> >
> > B is not a binary or tuple to size(B) should give badarg
> 
> There is indeed something fishy in the above...
> 
> But IMO, size/1 is one of these functions that should be considered
> deprecated and only kept for backwards compatibility.  These days
> there
> exist built-in functions tuple_size/1, byte_size/1, and bit_size/1
> that
> are unambiguous and more type-friendly.
> 
> I would urge Joe to avoid mentioning the existence of size/1 in the
> new
> edition of his book.

I agree with Kostis here. Don't mention it or if he does mention it then it should be so they can understand old code but with a word of warning not to use it.

I understand why it should work with bit strings, it would be strange if it didn't as it works on binaries. Though I think it should return 3 not 2, as byte_size/1 does for the same bit string in R15B01.

Robert


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