sub send {
   my $self = shift;
   return undef unless ref $self;
   my $sock = shift || $self{ERROR}->set(ILL_NUM);
   return 0 if $self->error->get;
   $self->{CONTENT_LENGTH} = length $self->{CONTENT};
   my $str = sprintf("%$self->{CODESIZE}s", $self->{CODE}) 
           . sprintf("%$self->{CONTENTSIZE}d", $self->{CONTENT_LENGTH})
           . $self->{CONTENT};
   my $length = length $str;
   local $\ = undef;
   my ($sent, $tsend) = (0, 0);
   while ($sent < $length) {
      unless ($tsent = $sock->send($str)) {
         $self->error->set(SOCK_SEND, $!);
         return 0;
      }
      $sent += $tsent;
      $tsent = 0;
   }
   1;
}