`if( ec == errc::success )` is an interesting solution to the NTSTATUS/HRESULT problem.
Oh if we could redo Boost.System with hindsight ... but that's always the case with any standardised Boost library bar none. A decade or two always shows up things no human could have possibly predicted. My colleagues on SG14 are keen to design a <system_error2> which does not suffer from any of the problems in <system_error>. And that may be the case we take in the end anyway. I am actually in the unusual position of being one of the few voices to feel that the existing <system_error> is serviceable, and that any of the <system_error2> proposals I've seen so far do not contribute enough effect on the *runtime* code quality as to be worth going through the travails of WG21 standardisation for. I mean, sure, you can make a much nicer for C++ <system_error2> using all the hindsight we have now. But you're not going to be using error codes unless you really care about performance, in which case runtime codegen is what you really care about much more than C++ niceness. And current <system_error> generates pretty optimally fast codegen, even on MSVC with its fenced error category fetches. My proposal would eliminate most of the remaining badness that I am aware of. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/