sub flag_status {
  my $v = $_[0];
  return is_IOK($v) | is_pIOK($v) | is_IsUV($v)
       | is_NOK($v) | is_pNOK($v);
}
sub is_IOK {
 # return 1 if argument's IOK flag is set
 # else return 0
}

sub is_pIOK {
 # return 2 if argument's pIOK flag is set
 # else return 0
}

sub is_NOK {
 # return 4 if argument's NOK flag is set
 # else return 0
}

sub is_pNOK {
 # return 8 if argument's pNOK flag is set
 # else return 0
}

sub is_IsUV {
 # return 16 if argument's IsUV flag is set
 # else return 0
}