static int aux_close (lua_State  * L) {
  LStream  * p  =  tolstream(L);
  volatile lua_CFunction cf  =  p -  > closef;
  p -  > closef  =  NULL;  / *  mark stream as closed  * /
   return  ( * cf)(L);  / *  close it  * /
}

static int f_close (lua_State  * L) {
  tofile(L);  / *  make sure argument is an open stream  * /
   return  aux_close(L);
}  

  static int io_fclose (lua_State  * L) {
  LStream  * p  =  tolstream(L);
  int res  =  fclose(p -  > f);
   return  luaL_fileresult(L, (res  =  =   0 ), NULL);
}  

static int aux_close (lua_State *L) {
  LStream *p = tolstream(L);
  volatile lua_CFunction cf = p->closef;
  p->closef = NULL;  /* mark stream as closed */
  return (*cf)(L);  /* close it */
}

static int f_close (lua_State *L) {
  tofile(L);  /* make sure argument is an open stream */
  return aux_close(L);
}

static int io_fclose (lua_State *L) {
  LStream *p = tolstream(L);
  int res = fclose(p->f);
  return luaL_fileresult(L, (res == 0), NULL);
}

function main()
  local filename = "file.txt"
  local f = assert(io.open(filename, "w"))
  os.execute("start cmd.exe")
  message(tostring(f:close()) .. "\n" .. tostring(f))
  assert(os.remove(filename))  -- file.txt: Permission denied
end