I have made a little program using an older version of threads and now it does not work properly.. So my little question what is wrong now? 1st thread is listening to my tcp-traffice (using NetPacket) $q = ".."; and pushes this a) { lock($PIPS); # only for 2nd thread!! $PIPS .= $q; # } and pushes it to a threaded chat-Array to send to any socket client that has been accepted: { lock(@chat); # push for sending to all push @chat, $qtsID."\t".$q; # $qtsID is an identifier not to send back to origine cond_signal(@chat); } 2nd thread takes this to do s.th with it: { lock($PIPS); $nPips = $PIPS; $PIPS = ''; } ... and pushes the result as well to the chat-Array.. { lock(@chat); push @chat; cond_signal(@chat); } # un-block vars block Finally pairs of threads were created when aksed for a socket-connection. The 'Reader' (here) just listens to know when to die: while(defined ($l = <$socket>) ){ # empty loop } { lock($NoClient); $NoClient--; } # if you want to kill the Writer immediately and not only after the next input: de-commet: { lock(@chat); cond_broadcast(@chat); } and the 'Sender' after sending some files send those performs: while( 1 ) { lock(@chat); cond_wait(@chat);# if (@chat); next unless (@chat); ... foreach (@chat) { ... print $SOCKET ... } } Well this has worked, but now - I think - it blocks everything right after the first client has died... Do I just have to put bracktes within while(1) ? while( 1 ) { {# add bracket open lock(@chat); cond_wait(@chat); next unless (@chat); ... foreach (@chat) { ... print $SOCKET ... } } # add bracket close }