Exceptions seem to lack information about mailio

[karastojko]

You are right, I will address the issue in the future.

[firedaemon-cto]

In this sense I wonder what's the design decision behind catching asio (ssl) errors and rethrow them as mailio errors? Because asio is such a vital core part of the communication layer, we definitely need the underlying communication error.
I personally would let asio errors through to the caller, as they are std::system_errors these days anyway.

[karastojko]

It was meant to move them away as low level errors. But from your and some other comments, I see there is a need to trace these errors as well the errors received from servers. Thus, I plan to extend the mailio exceptions with these additional data. In this version I am dealing with the various encoding issues, so probably I'll let the error handling for the next version.