in reply to Re^2: Lost anonymous subs
in thread Lost anonymous subs

This is all perl internals, perlguts stuff. The CV you get in $code has an ->OUTSIDE C pointer to the PADLIST that @arr lives in and then the compiled code has a note on which index in that PADLIST it is suppposed to access the @arr at. So it isn't a copy. The code in $code works with the real, original @arr, not a copy.

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Re^4: Lost anonymous subs
by kappa (Chaplain) on Dec 09, 2004 at 15:49 UTC
    Please, say that the comments down there in the code are right and I will rest calm, thankful and a bit more knowledgable :) 
    my $code;
{
    my @arr = (9) x 1000_000;
    $code = sub { @arr };
}
# here @arr got out of the scope but is not freed as 
# there's a ref from inside $code closure
# which enables $code do things with the array when called
undef $code;
# only now that million of nines has gone away
# it always existed in exactly one copy

    [download]
    --kap
[reply]
[d/l]

      Your comments were unintelligble

      Here is what happens. Your million nines will continue to stick around as long as $code does. Once you lose the last link to $code then your million nines will also be gone.

[reply]
        Looked intelligible to me. And the comments agree with what you say.
[reply]

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