Function luaL_optlstring

lua/lauxlib.c:202–210

LUALIB_API const char *luaL_optlstring (lua_State *L, int narg,
                                        const char *def, size_t *len) {
  if (lua_isnoneornil(L, narg)) {
    if (len)
      *len = (def ? strlen(def) : 0);
    return def;
  }
  else return luaL_checklstring(L, narg, len);
}


LUALIB_API lua_Number luaL_checknumber (lua_State *L, int narg) {