sub x{
  local(*A)=$_[0];
  if(opendir(R,"/usr")){x(*R);
  }
}

##</code><code>##

sub x{
  local(*A)=$_[0];
  if (opendir(R,"/usr")){while(<R>){print;}
  }
} 

##</code><code>##

[s0ttle@ween]%perl subtest
Read on closed filehandle <C> at a line 23.
[s0ttle@ween]%fuq
fuq: Command not found.
[s0ttle@ween]%