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.