On Fri, 2007-08-24 at 11:52 -0700, JT Moree wrote:
> JT Moree wrote:
> >
> > Is this uique enough? what is the chance of getting the same random
> > number again? should it be a combination of the PID + time + rand?
> >
>
> my @sname = split(/\./, $self->qp->config("me"));
> = $sname[0].$$.'r'.int( (( time ^ $$ ) * rand($$)) / rand(time/$$));
>
> = sprintf("%08X", rand(2**32 - 1));
>
> $self->qp->config("me") =~ m/\.(\d{1,3}$/; #not tested
> $self->{_id} = $1;
> = sprintf("%.4f%d", time(), $self->{_id});
>
> = sprintf("%.4f", time()) .".". $self->qp->config("me") . \
> sprintf("%08X", rand(2**32 - 1)); #how expensive is this?
>
> These are the approaches suggested so far. I added the last one as a
> combination of the others. Can we see a show of hands for the one
Using rand is bogus. A random number generator will repeat values.
Time (with sufficient resolution) is equivalent to a sequence ... but
with threads, you would need a lock on the sequence generator.
> people like the best?
>
> Can we get Hanno to modify his patch if people like one of these
> approaches? Can we get it tested by some people? Can we get it checked
> into svn?
--
--gh
