[Patch] include <bits/functexcept.h> in <variant>

[Tim Shen]

On Fri, Oct 14, 2016 at 2:31 AM, Jonathan Wakely wrote:
> Yes, that's right. OK for trunk, thanks.

Committed.

> By the way, I'm intending to add __throw_bad_variant_access_fmt to
> bits/functexcept.h and make it use __snprintf_lite() so that we can
> do:
>
>       __throw_bad_variant_access_fmt("cannot access alternative %zu "
>           "of std::variant because index() is %zu", _Np, __v.index());
>
> (Thanks to Nico Josuttis for the suggestion).
>

It's great to be able to print runtime indices in an exception
message! I could have used this for std::regex exceptions too.


-- 
Regards,
Tim Shen