Re: Supporting C++17

[Jonathan Wakely <gtkmm kayari org>]

On 4 April 2017 at 22:56, Chris Vine wrote:
> I would check that.  It didn't affect ABI in C++11/14, but I am not so
> sure about C++17.  According to
> http://en.cppreference.com/w/cpp/language/noexcept_spec,
> in C++17 "The noexcept-specification is a part of the function type and
> may appear as part of any function declarator."  If it is part of the
> type then it might feature in name mangling, so this is worth checking
> with the compiler writers.

In C++17 the exception spec is part of the type, so noexcept(true)
functions are mangled differently from functions that are
noexcept(false).

But functions with dynamic exception specification aren't
noexcept(true), so they're not mangled as noexcept(true) functions
would be.

If you replace the throw(std::bad_cast) with neoxcept(false) (or,
equivalently, omit the exception specification entirely) they still
aren't noexcept(true).

Here's the proof:
https://paste.fedoraproject.org/paste/Pwm-rv4LGXKh2EDVJSeOEl5M1UNdIGYhyRLivL9gydE=/

N.B. I didn't say that exception specifications don't affect the type,
I said that removing the deprecated dynamic exception specification,
i.e. throw(std::bad_cast), doesn't affect the type. Because it's still
a noexcept(false) function.