Function io_readline

extlibs/lua/src/liolib.c:615–641

** Iteration function for 'lines'. */

** Iteration function for 'lines'.
*/
static int io_readline (lua_State *L) {
  LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1));
  int i;
  int n = (int)lua_tointeger(L, lua_upvalueindex(2));
  if (isclosed(p))  /* file is already closed? */
    return luaL_error(L, "file is already closed");
  lua_settop(L , 1);
  luaL_checkstack(L, n, "too many arguments");
  for (i = 1; i <= n; i++)  /* push arguments to 'g_read' */
    lua_pushvalue(L, lua_upvalueindex(3 + i));
  n = g_read(L, p->f, 2);  /* 'n' is number of results */
  lua_assert(n > 0);  /* should return at least a nil */
  if (lua_toboolean(L, -n))  /* read at least one value? */
    return n;  /* return them */
  else {  /* first result is false: EOF or error */
    if (n > 1) {  /* is there error information? */
      /* 2nd result is error message */
      return luaL_error(L, "%s", lua_tostring(L, -n + 1));
    }
    if (lua_toboolean(L, lua_upvalueindex(3))) {  /* generator created file? */
      lua_settop(L, 0);  /* clear stack */
      lua_pushvalue(L, lua_upvalueindex(1));  /* push file at index 1 */
      aux_close(L);  /* close it */
    }
    return 0;
  }
}

/* }====================================================== */