Something is leaking

mogul has asked for the wisdom of the Perl Monks concerning the following question:

While fiddling with some SNMP code I stumbled across a leak or something. Example code: (yes, I know it will never get anything with Timeout=>0)

#!/usr/bin/perl
use strict;
use warnings;
use SNMP;
use Data::Dumper;

main();

sub main
{
  for my $item ('something that leaks', 'more leaking stuff')
  {
    doit();
  }
}

sub doit
{
  my $session = new SNMP::Session(DestHost  => '127.0.0.1',
                                  Community => 'DoesNotWork', 
                                  Timeout   => 0,
                                  Version   => '2c');
  my $x = $session->bulkwalk(0, 1, ['.1.3.6.1.2.1.1.1']);
  die 'DUMP IT: ' . Dumper \$x;
}
[download]

and the output:

DUMP IT: $VAR1 = \[
            'something that leaks',
            'more leaking stuff',
            undef
          ];
[download]

How did those two constants end up in the output?

os: kubuntu-10.04
perl: v5.10.1
libsnmp-perl: 5.4.2.1~dfsg0ubuntu1-0ubuntu2.1
[download]

Comment on Something is leaking Select or Download Code

Replies are listed 'Best First'.
Re: Something is leaking by dave_the_m (Monsignor) on Mar 05, 2011 at 20:48 UTC
Looks most likely a bug in Net::SMTP that's corrupting the stack Dave.	[reply]
Re^2: Something is leaking by mogul (Novice) on Mar 06, 2011 at 06:29 UTC
Hmm, it was what I feared. I'l see if I can find somewhere to file a bug report. Thanks for your time, all of you!	[reply]
Re^2: Something is leaking by repellent (Priest) on Mar 05, 2011 at 22:09 UTC
Did you mean Net::SNMP instead?	[reply]
Re^3: Something is leaking by dave_the_m (Monsignor) on Mar 05, 2011 at 22:22 UTC
Did you mean Net::SNMP instead A brain fart! Presumably I meant the SNMP module. Dave.	[reply]
Re: Something is leaking by Khen1950fx (Canon) on Mar 05, 2011 at 20:19 UTC
Those two constants ended up in the output because you used `for`. I would use `unless` instead. #!/usr/bin/perl use strict; use warnings; use SNMP; use Data::Dumper; my $hostname = '127.0.0.1'; my $community = 'DoesNotWork'; $SNMP::verbose = 1; $SNMP::debugging = 1; main(); sub main { my @item =('something that leaks', 'more leaking stuff'); unless (not @item) { doit(); } } sub doit { my $session = new SNMP::Session('DestHost' => $hostname, 'Community' => $community, 'Timeout' => 0, 'Version' => '2c'); my $x = $session->bulkwalk(0, 1, ['.1.3.6.1.2.1.1.1']); warn 'DUMP IT: ' . Dumper(\$x); } [download]	[reply] [d/l] [select]
Re^2: Something is leaking by GrandFather (Saint) on Mar 05, 2011 at 20:46 UTC
What do you think is happening in the OP's code and how does your change fix the problem? True laziness is hard work	[reply]
Re^3: Something is leaking by Khen1950fx (Canon) on Mar 05, 2011 at 21:31 UTC
I was thinking that the OP wanted a test failure, so I tried reversing the sense of the test to get around the freed value warning. How would you handle it? Thanks for the response.	[reply]
Re^4: Something is leaking by GrandFather (Saint) on Mar 05, 2011 at 22:18 UTC
Re^2: Something is leaking by mogul (Novice) on Mar 06, 2011 at 06:22 UTC
No no, my whole point was not to touch or use $item or any of the two constants after their declaration. And still they get printed.	[reply]