my $str_with_length =  pack("N/a*", $some_data);
$sock->send($str_with_length);

##</code><code>##

while (read ($sock, $buf, 4) != 0) {last;};
my $length = unpack("N", $buf);
read ($sock, $input_str, $length);

##</code><code>##

binmode $sock;