Function checkclosemth

3rd/lua-5.4.3/src/lfunc.c:126–134

** Check whether object at given level has a close metamethod and raise ** an error if not. */

** an error if not.
*/
static void checkclosemth (lua_State *L, StkId level) {
  const TValue *tm = luaT_gettmbyobj(L, s2v(level), TM_CLOSE);
  if (ttisnil(tm)) {  /* no metamethod? */
    int idx = cast_int(level - L->ci->func);  /* variable index */
    const char *vname = luaG_findlocal(L, L->ci, idx, NULL);
    if (vname == NULL) vname = "?";
    luaG_runerror(L, "variable '%s' got a non-closable value", vname);
  }
}


/*