comment on

First of all, I want to thank you for you help :) I been struggling with this a while now.
When you say that I Implicitly shares objects across threads, how is this possible?
If I don't pass an object as an argument or uses an external global object in the thread, how can It share them. Are all objects that are in the same scope (i.e. sub routines, class) automatically shared without me using it. :\

To the program. I have included my original program an a working one that is not what I first had in mind and I don't know why it works, thats frightens me a bit ;).
Your code is close to want I wanted but it will not work in my case. The IO::Telnet-socket is the one who writes to $io so I cant access it because of the issue of sharing objects you told me. Instead the Update()-thread uses $var to update the screen and Telnet-socket output is connected to $io in the main thread.

With the small test program it was impossible to know how the program was composed so I have included my code and stripped all special features for easy reading.
This is how it is suppose to work. This class i called from another perl-module like run("192.168.0.1","23"). It uses Telnet to extract information from various devices and views it on screen and logs it on disc FileIO::save_log("traffic_log.txt",$var) by using $var as intermediate storage. IO::Telnet-socket is connected to $var through $sock->input_log($io).
The program is going to have several instances of run(...) working in parallell by using threads later on. Each instances has a thread Update() that updates screen with its traffic.
For all devices I going to have several program1()-subroutines. Because of all the instances of run(...)-threads I want as few class-variables as possible and declare them inside run(...)-subroutine.
This is how the original program looked like.

package CodeExecutor;

use strict;
use Net::Telnet;
use threads;
use threads::shared;
#require "fileio.pl";

my $finished : shared=0; # Thread control var 

run("192.168.0.1","23");

sub run{
    my $IP=shift;
    my $Port=shift;
    my $sock=getConnection($IP,$Port); # Get a telnet socket
    my $var:shared;                    # Traffic storage var
    require 'IO/String.pm';
    my $io = IO::String->new($var);
    $sock->input_log($io);      # Connect socketstream to $var    
    my $th=threads->new(\&Update,\$var); # Start update thread
    program1($sock);                     # Run the program
    $th->join();                         # Collect the thread
    if(defined $sock){
      print "connection successful:".$sock;
      $sock->close();
    }
}
 
sub program1{
    my $sock=shift;
    eval{
        print "Start";
        $sock->waitfor('/Password:/');
        $sock->print("cisco");
        $sock->waitfor('/Router>/');
        $sock->print("en");
        $sock->waitfor('/Password:/');
        $sock->print("cisco2");
        $sock->waitfor('/Router#/');
        sleep(2);
        $sock->print("show aliases");
        $sock->waitfor('/Router#/');
        $sock->print("show file systems");
        $sock->waitfor('/Router#/');
    };
    if ($@){
        print "Match Timeout";
    }
    {lock $finished; $finished=1;} # Tells threads to stop
    #FileIO::save_log("traffic_log.txt",$var); # Save log to file
}

sub getConnection{
    my $destIP=shift;
    my $destPort=shift;
    my $sock;
    eval{
        $sock=new Net::Telnet(Host=>$destIP,
                             Port=>$destPort,
                             Timeout=>"20");
    };
    if ($@){
        print "Could not get a connection";
        exit(0);
    }
    return $sock;   
}

# Update the screen with new Traffic
#  contained in $var
sub Update{
    my $var=shift;
    my $linenr=0;
    while(1){
      my @bufflines=split(/\n/,$$var);
      # Print new lines only
      while($linenr<$#bufflines){
        print $bufflines[$linenr++]."\n";
      }
      {lock $finished; return if $finished;}
      sleep(1); # Update intervall
    }
}
1; # Returning a true value
[download]

Now to the working one. The changes are:

The IO::String is moved to the program1() because with it in run(...) (with the thread creation) caused my warnings.
As an effect I have to move $var out of run(...) to be a class variable
Update can now read $var directly without passing as argument

Here is the working code:

package CodeExecutor;

use strict;
use Net::Telnet;
use threads;
use threads::shared;
#require "fileio.pl";

my $finished : shared=0; # Thread control var 
my $var:shared;          # Traffic storage var

run("192.168.0.1","23");

sub run{
    my $IP=shift;
    my $Port=shift;
    my $con=getConnection($IP,$Port);  # Get a telnet socket
    my $th=threads->new(\&Update);     # Start update thread
    program1($con);                    # Run the program
    $th->join();                       # Collect the thread
    if(defined $con){
      print "connection successful:".$con;
      $con->close();
    }
}
 
sub program1{
    my $sock=shift;
    require 'IO/String.pm';
    my $io = IO::String->new($var);
    $sock->input_log($io);    # Connect socketstream to $var
    eval{
        print "Start";
        $sock->waitfor('/Password:/');
        $sock->print("cisco");
        $sock->waitfor('/Router>/');
        $sock->print("en");
        $sock->waitfor('/Password:/');
        $sock->print("cisco2");
        $sock->waitfor('/Router#/');
        sleep(2);
        $sock->print("show aliases");
        $sock->waitfor('/Router#/');
        $sock->print("show file systems");
        $sock->waitfor('/Router#/');
    };
    if ($@){
        print "Match Timeout";
    }
    {lock $finished; $finished=1;} # Tells threads to stop
    #FileIO::save_log("traffic_log.txt",$var); # Save log to file
}

sub getConnection{
    my $destIP=shift;
    my $destPort=shift;
    my $con;
    eval{
        $con=new Net::Telnet(Host=>$destIP,
                             Port=>$destPort,
                             Timeout=>"20");
    };
    if ($@){
        print "Could not get a connection";
        exit(0);
    }
    return $con;   
}

# Update the screen with new Traffic
#  contained in $var
sub Update{
    #my $var=shift;
    my $linenr=0;
    while(1){
      my @bufflines=split(/\n/,$var);
      while($linenr<$#bufflines){
        print $bufflines[$linenr++]."\n";
      }
      {lock $finished; return if $finished;}
      sleep(1);
    }
}
1; # Returning a true value
[download]

This code works but is not so good if I want to create multiple threads of this class. On the otherhand, maybe I am not doing it the right way... As usual, all inputs are highly appreciated.
Thanks again for the help! ;)

In reply to Re^2: Problem with using threads with modules. by tele2mag
in thread Problem with using threads with modules. by tele2mag

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