Thank you very much for your help...

The second EV::loop does work - but I don't understand why - I thought the first EV::loop starts the main loop which runs until EV::unloop is called or all watchers stopped...?

Anyway I found the reason why handle_client isn't called in my code:

my $w = EV::io $client, EV::READ, \&handle_client;
[download]

because of "my" $w runs out of scope immediately and so the watcher stops. so there must be a hash or array where to store the watcher handles for every socket. The complete working code looks like this:

use strict;
use IO::Socket;
use EV;

my $connection_count = 0;
my $h;
my %h;

my $server = new IO::Socket::INET (
LocalPort => 2345, Type => SOCK_STREAM,
Listen => SOMAXCONN, Reuse => 1
);

my $w = EV::io $server, EV::READ, \&handle_incoming;
EV::loop;

sub handle_incoming
{
      my $w=shift;

      my $fh=$w->fh->accept or die;

      $h->{$fh} = EV::io $fh, EV::READ, \&handle_client;

      printf "new socket connection #%d (%d)\n", ++$connection_count, 
+scalar keys %$h;
}


sub handle_client
{
      my $c=shift;
      my $fh=$c->fh;
      my $bytes_read=sysread($fh, my $bytes, 9_999_999);

      return if (not exists $h->{$fh});

      printf "in=%s (%d bytes)\n",$bytes,$bytes_read;

      if (($bytes eq 'q') || ($bytes_read == 0)) {
          close($fh);
          undef $c; # destroy event watcher
          delete $h->{$fh};
          printf "socket connection terminated by %s (%d (%d) sockets 
+remaining)\n", $bytes_read == 0 ? 'peer' : 'server', --$connection_co
+unt, scalar keys %$h;
      }
}
[download]

(Thanks and Greetings to Simon :-)

Walchy