Hibp | A little scraper that scrapes HaveiBeenPwned 's top 10 list | Scraper library

You can put std::ofstream ofstream_; in a separate struct, then have flat_file_writer inherit from that struct using private. Base classes are initialized in the order they are declared, so make sure to inherit from that struct before flat_file_stream_writer. You can now initialize that ofstream_ before the base class flat_file_stream_writer.

On closer inspection, I think you'll probably want to put all 3 of those members in the struct.

See below for updated code.

So this in effect means that the 3 members in ofstream_holder now come before the flat_file_stream_writer in the layout of flat_file_writer.

This seems like the right solution, not just because it "squashes the compiler warning", but because now we are really getting the correct initialization order, ie construct the std::ofstream first and then pass a reference to it to flat_file_stream_writer. And during destruct the std::ofstream will be destroyed last.

The original code above had this exactly the wrong way around, because the order we write in the derived constructor initializer is ignored and the actual order implemented is layout order, ie the order the members are declared.

(despite the flaws of the original code, it "ran fine" for me with sanitizers etc... but was probably UB?).