Simply commenting it out is not an option, but the following should do the trick 
```cpp
ids.resize(run_Name_ID_map_.size());
std::transfrom(run_Name_ID_map_.begin(), run_Name_ID_map_.end(), ids.begin(), op_getkey);
```
with 
```cpp
String op_getkey (const std::pair<String, String>& p) { return p.first; }
```