On the chatterbox somebody (sorry for forgetting
who did help me) suggested me to use closures.
I did it and it worked fine. The example
code follows below. Thanks everyone for the
inspiration!
sub gpib_write {
  my ($self, $command) = @_;

  print "Sending ->$command<- to gpib ud=$self->{ud}.\n" if ($debug);
  
  my $message = "GPIB|write|$self->{ud}|$command";

  # Send message to gpib server
  $self->{conn}->MessageSend(to=>'gpibserver@xxx.yyy.zzz',
                      subject=>"",
                      type=>"groupchat",
                      body=>$message,
                      thread=>"",
                      priority=>10);
  print "  Message sent: ->$message<-\n" if ($debug);
    
  # Acknowledge comes through callback
  my $answer;
  $self->{conn}->SetCallBacks(
    message=>sub{    my $sid = shift;
                     my $message = shift;
                     my $body = $message->GetBody();
                        
                     print "    Acknowledge received: ->$body<-\n" if 
+($debug);
                                
                     $answer = $body;
                }
  );
  return $answer;
}

[download]

In reply to Re^2: Net::Jabber: Receiving answers without callbacks by enhering
in thread Net::Jabber: Receiving answers without callbacks by enhering

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.