in reply to threads and leaking scalars

I had this very same problem, and I finally figured it out.
If you change this line (in new()): 
  my ( $pkg,$config ) = @_;

[download]
To this: 
  my $pkg    = shift;
  my $config = shift;

[download]
then it will work.

I suspect that there's too much magic associated with the @_ variable to let threads play nicely with it. So, my recommendation is to *not* use @_ in the same scope as you launch new threads.

Update:
Unfortunately, including other modules (say, XML::DOM) may cause this same problem, so you'd have to launch all of your threads before bringing in such modules. This might be a good use for Thread::Pool...

Replies are listed 'Best First'.
Re^2: threads and leaking scalars (Scalars leaked: 1)
by myuserid7 (Scribe) on Mar 21, 2008 at 00:37 UTC
    dpmott, If you are still here--THANK YOU! This has to be one of the nastiest perl warnings to track down. You have saved me many more days of frustration.
[reply]
Re^2: threads and leaking scalars (Scalars leaked: 1)
by ikegami (Patriarch) on Mar 21, 2008 at 01:09 UTC

    So, my recommendation is to *not* use @_ in the same scope as you launch new threads.

    shift (in a sub) and shift(@_) result in exactly the same code, so you are still using @_. 

    >perl -MO=Concise,x -e"sub x { shift }
main::x:
5  <1> leavesub[1 ref] K/REFC,1 ->(end)
-     <@> lineseq KP ->5
1        <;> nextstate(main 1 -e:1) v ->2
4        <1> shift sK/1 ->5
3           <1> rv2av[t2] sKRM/1 ->4
2              <#> gv[*_] s ->3
-e syntax OK

>perl -MO=Concise,x -e"sub x { shift(@_) }
main::x:
5  <1> leavesub[1 ref] K/REFC,1 ->(end)
-     <@> lineseq KP ->5
1        <;> nextstate(main 1 -e:1) v ->2
4        <1> shift sK/1 ->5
3           <1> rv2av[t2] lKRM/1 ->4
2              <#> gv[*_] s ->3

    [download]
[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom