[RFC v2 1/3] cdefs: Add __bool

[Alejandro Colomar]

Hi Collin,

On Tue, Sep 02, 2025 at 08:06:23AM -0700, Collin Funk wrote:
> Alejandro Colomar <alx@kernel.org> writes:
> 
> >> Hmmmm, true.  Can we drop support for compilers that don't have
> >> _Bool/bool?  That would be the easiest thing to do:
> >> 
> >> 	#if defined __cplusplus
> >> 	# define __bool  bool
> >> 	#else
> >> 	# define __bool  _Bool
> >> 	#endif
> >
> > Self-reply:
> >
> > This seems entirely possible, given the glibc documentation requires
> > GCC 12.1 at least.
> > <https://sourceware.org/glibc/manual/latest/html_node/Tools-for-Compilation.html>
> 
> We shouldn't use _Bool in C23 since compilers are free to stop
> supporting it at any time. You can use the expression
> "202311L <= __STDC_VERSION__".

They're not.  C2y still specifies _Bool as mandatory.
<https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3550.pdf#table.0.6.1>

They're obsolescent, but their dawn hasn't come yet.

The standard says:

	These [alternative spellings] can be used wherever the keyword can.


Have a lovely day!
Alex

-- 
<https://www.alejandro-colomar.es>
Use port 80 (that is, <...:80/>).
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