C++17 STL Cookbook

How it works...

We have seen that we can enable exceptions per stream object, s, with s.exceptions(s.failbit | s.badbit). This means, that there is no way to use, for example, the std::ifstream instance's constructor for opening a file if we want to get an exception when opening that file is not possible:

ifstream f {"non_existant.txt"};f.exceptions(...); // too late for an exception

This is a pity because exceptions actually promise that they make error handling less clumsy compared to old-school C-style code, which is riddled with loads of if branches, which handle errors after every step.

If we played around trying to provoke various reasons for streams to fail, we would realize that there are no different exceptions being thrown. This ...