Jens Maurer wrote:

>> Maybe one way out of the naming problem is to say that
>> C++ retains its model that std::float16 (etc.) is an alias to
>> an unnamed fundamental type plus say that the typedef _Float16
>> is introduced in <cmath> and <math.h>, referring to that same type.

I kind of like that idea. It might work. I will think it over some more and maybe incorporate it into P1467. Thanks for the suggestion.

What do other people think about it?


-----Original Message-----
From: Ext <ext-bounces_at_[hidden]> On Behalf Of Jens Maurer via Ext
Sent: Friday, September 17, 2021 6:22 AM
To: Aaron Ballman <aaron_at_[hidden]>; Evolution Working Group mailing list <ext_at_[hidden]>
Cc: Jens Maurer <Jens.Maurer_at_[hidden]>; SG6 numerics <sci_at_[hidden]>; Matthias Kretz <m.kretz_at_[hidden]>; WG14/WG21 liaison mailing list <liaison_at_[hidden]>
Subject: Re: [isocpp-ext] [wg14/wg21 liaison] Report from the recent C/C++ liaison meeting (SG22); includes new floating point types(!)


On 17/09/2021 13.56, Aaron Ballman wrote:
> FWIW, it's sounding more and more to me like there's high risk for
> user confusion and incompatibilities between C and C++ in this space
> and we should consider a joint meeting with the C Floating Point Study
> Group to see what can be done in both committees to reduce that
> likelihood. I'm planning to discuss P1467 in SG22 on Oct 1, and I will
> invite the CFP group (as well as others in WG14) to attend.

Well, given the current scheduling, it is very likely that C
just goes ahead with what they have (they've been working on
it for years), and C++ won't do anything for C++23 due to timing
constraints.

Maybe one way out of the naming problem is to say that
C++ retains its model that std::float16 (etc.) is an alias to
an unnamed fundamental type plus say that the typedef _Float16
is introduced in <cmath> and <math.h>, referring to that same type.

This way, C code that uses _Float16 would just work if the code
included <math.h>, which seems likely.
Yet, we get away with not officially introducing _Ugly keywords
in C++. And since a type name and an alias pointing to that type
is indistinguishable in C++, compilers might just happen to treat
_Float32 as a keyword instead of an alias.

Jens