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Re^3: Using fork with DBI to create simultaneous db connections.

by etcshadow (Priest)
on Feb 08, 2005 at 05:34 UTC ( #428931=note: print w/replies, xml ) Need Help??


in reply to Re^2: Using fork with DBI to create simultaneous db connections.
in thread Using fork with DBI to create simultaneous db connections.

Actually, that's incorrect, and it's probably the same mistake that the original poster made. The flaw is that the memory address shown as part of the stringification of the reference is the *relative* memory address to that process. The operating system uses something called "virtual memory", which abstracts the actual *physical* memory location away from your processes. In truth, the physical memory addresses may change from time to time, as your process is swapped and paged and so on.

Anyway, here's a quick demo:

prompt> perl -le 'my $pid = fork; my $x = [$pid]; print "$x->[0] -- $x +"' 0 -- ARRAY(0x80d11ec) 24694 -- ARRAY(0x80d11ec) prompt>
You can see that each process has it's own array, with the reference stored in $x, yet in both processes, the memory address appears the same.
------------ :Wq Not an editor command: Wq

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Re^4: Using fork with DBI to create simultaneous db connections.
by thor (Priest) on Feb 08, 2005 at 12:46 UTC
    Hell...I learned something. Not that that's bad...I just don't like being wrong. :)

    thor

    Feel the white light, the light within
    Be your own disciple, fan the sparks of will
    For all of us waiting, your kingdom will come

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