Re: Draft C2Y _BitInt related proposals

Am Mittwoch, dem 08.07.2026 um 15:19 +0200 schrieb Florian Weimer:
> * Jakub Jelinek via Gcc:
> 
> > As I wrote earlier, I'd like to see _BitInt I/O support in
> > *printf*/*scanf* and extending support of _BitInt in stdbit.h
> > in C2Y.
> > 
> > For those I wrote drafts of possible C2Y papers:
> > https://jakubjelinek.github.io/wg14/va_arg_bitint.html
> > https://jakubjelinek.github.io/wg14/stdbit_bitint.html
> > 
> > I'd appreciate any comments on this.
> 
> Is this going in the right direction, though?
> 
> Why shouldn't programmers be able to write %d in the format string and
> print _BitInt arguments this way?
> 
> I think it's time to pass a type descriptor for varags functions.  Then
> it wouldn't be necessary to pass the _BitInt size as argument to
> va_arg_bitint.

I agree that this would be the right overall direction.  I want
type descriptors for C anyway for various reasons.  It is a 
bigger project though and seems a bit orthogonal to supporting
_BitInts properly with the current mechanism.

Btw the fmt library now also has some C support, where you can
write

print("The value is {}\n", 488);

it is based on _Generic not type descriptors though.
With Jakub's built-ins could potentially be extended to _BitInts
as well.

https://github.com/fmtlib/fmt/blob/main/include/fmt/fmt-c.h

Martin