The answer is 'use a thread'. Now the question becomes, what are you doing with the input from the stream?

I keep on reading the stream. I´m saving information of coming commands.

# Keep reading lines from the server.
while (my $input = <$server>) {
 #save incoming information to database ... do this and that
 # Check errormessages and ....
}
[download]

But I would still like to use the frontend

This ain't gonna do what you need to do, but given the sparsity of information supplied...

use threads;

...

async{
    # Keep reading lines from the server.
    while (my $input = <$server>) {
     #save incoming information to database ... do this and that
     # Check errormessages and ....
    }
};
[download]

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

thanks i´ll try

Try this. It's a starting point.

#! perl -slw
use strict;
use threads;
use Win32::GUI;

my $mw =  Win32::GUI::Window->new(
    -name   => 'Main',
    -width  => 500,
    -height => 500,
);
my $lb = $mw->AddListbox( -name => 'LB' );

$lb->Add( 'Line ' . $_ ) for 1 .. 10;

$mw->Show();

my $thread = async{
    my $lb = shift;
    $SIG{'KILL'} = sub { return 0; };
    my $n = 11;
    while( sleep 1 ) {
        $lb->Add( 'Line ' .  $n++ );
    }
} $lb;
$thread->detach;

Win32::GUI::Dialog();

exit(0);

sub Main_Terminate {
    $thread->kill( 'KILL' );
    return -1;
}

sub Main_Resize {
    $lb->Width( $mw->Width );
    $lb->Height( $mw->Height );
}

sub LB_Click {
    print 'click';
}

sub LB_MouseRightDown {
    print 'Rclick';
}
[download]

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."