Re: [boost] [system] Would it be possible to trial a breaking change to Boost.System and see what happens?

Subject: Re: [boost] [system] Would it be possible to trial a breaking change to Boost.System and see what happens?
From: Peter Dimov (lists_at_[hidden])
Date: 2018-01-13 15:20:19

> Andrey Semashev wrote:
>
> > I don't think the standard requires this implementation. 
> > `system_category()` may return a pointer to a global caregory instance, 
> > which is initialized before `main`.
>
> You're not prohibited from calling system_category() before main, so it 
> has to work.

You can see for yourself what happens in practice today: 
https://godbolt.org/g/1TfPQw

The g++/clang++ generated code looks cleaner than that, but it's because it 
doesn't include system_category(). Here it is in libc++: 
https://github.com/llvm-mirror/libcxx/blob/master/src/system_error.cpp#L211

MS's code is even more convoluted because their <system_error> works during 
process shutdown, after static destruction. But the magic static cost is the 
same in either case.