sub getsockopt_darwin_gen {
  return &CORE::getsockopt if(@_ < 4);
  my $optlen = pop;
  my $optval = "\0" x $optlen;
  $optlen=pack('i',$optlen);
  my $rv=syscall(DARWIN_SYS_getsockopt,fileno($_[0]),$_[1],$_[2],$optval,$optlen);
  return $rv < 0 ? undef : substr($optval,0,unpack('i',$optlen));
}