void
smh_peercred(s)
    PerlIO* s;
PROTOTYPE: $
PPCODE:
{
# ifdef SO_PEERCRED
  struct ucred uc;
  socklen_t uc_len=sizeof(uc);

  if( !getsockopt(PerlIO_fileno(s), SOL_SOCKET, SO_PEERCRED, &uc, &uc_len) ) {
    EXTEND(SP, 3);
    PUSHs(sv_2mortal(newSViv(uc.pid)));
    PUSHs(sv_2mortal(newSViv(uc.uid)));
    PUSHs(sv_2mortal(newSViv(uc.gid)));
  }
# else
  SETERRNO(EOPNOTSUPP, RMS_IFI);
# endif
}