string s = "";if (s.empty()) {
      cout << "字符串为空。。"; } else {
      cout << "字符串不为空。。"; }

¦ char value[PROP_VALUE_MAX];

¦ int rc = property_get(prop_map[i].src_prop, value);

¦ property_set(prop_map[i].dst_prop, (rc > 0) ? value : prop_map[i].default_value);