#!/usr/bin/perl

use strict;
use warnings;
use threads;

my $th1 = threads->create(\&run, 1);
my $th2 = threads->create(\&run, 2);

sleep;
exit;

sub run {
  my $num = shift;
  my ($bus, $service, $purple);

  eval {$bus = Net::DBus->session}; 
  if ($@) {print "th$num: Error in bus: $@\n"; threads->exit()}
  
  eval {$service = 
      $bus->get_service('im.pidgin.purple.PurpleService') };
  if ($@) {print "th$num: Error in service: $@\n"; threads->exit()}

  eval {$purple = 
      $service->get_object('/im/pidgin/purple/PurpleObject', 
                            'im.pidgin.purple.PurpleInterface')};
  if ($@) {print "th$num: Error in purple: $@\n"; threads->exit()}
  
  eval {$purple->connect_to_signal ('ReceivedImMsg', \&read_cb)};
  if ($@) {print "th$num: Error in connect: $@\n"; threads->exit()}

  eval {Net::DBus::Reactor->main()->run()};
  if ($@) {print "th$num: Error in run: $@\n"; threads->exit()}
}

sub read_cb {
  print scalar(@_) , ' params', "\n";
}
[download]

So get bus, get service, get object, set callback and run. This works very well single threaded. Here is the output of this particular script:

th1: Error in service: Can't call method "get_interval" without a pack
+age or object reference at /usr/lib/perl5/Net/DBus/Reactor.pm line 21
+1.

Thread 1 terminated abnormally: Can't call method "get_interval" witho
+ut a package or object reference at /usr/lib/perl5/Net/DBus/Reactor.p
+m line 211.
th2: Error in service: org.freedesktop.DBus.Error.NoMemory: Not enough
+ memory

Thread 2 terminated abnormally: main=HASH(0x9ffd850) at /usr/lib/perl5
+/threads.pm line 101.
[download]

Trying to add a lock makes it better up to the run(), which will fail with the same kind of error if it is not inside the lock (which would defeat the purpose).

Would somebody know what is wrong with this code? Following the advice of http://perldoc.perl.org/threads.html#WARNINGS, instead of use'ing the DBus modules I tried to require them inside the thread, with no effect.

If it helps, the background is the following:

• A thread listen to the purple object, and add values in a shared structure
• A pool of threads take actions on this structure, push results on a queue
• A last thread uses the purple object to send this data back.

Thanks for any advice or pointer on this.