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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: Is bool no longer a primitive data type of C/C++ ?
Date: Sun, 29 Nov 2020 17:42:18 -0800
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Richard Damon <Richard@Damon-Family.org> writes:

>> On 29/11/2020 09:14, Tim Rentsch wrote:
>>
>>> Is there anything in the C standard that would preclude the
>>> type 'enum Boolean{false, true}' from having a compatible
>>> type of _Bool?  I looked but didn't see anything.
>
> Could the implementation define an extended integer type that had
> sizeof = sizeof bool, and only 1 value bit and the rest be padding
> (with a non-zero value of the padding being a trap representation)
> and then make the enum be compatible with that type?

The compatible type chosen for an enum may be an extended integer
type.

AFAICS an implementation may offer a pair of extended integer
types (one signed, one unsigned) with a width of one and a size
of any integral power of two bytes (which sizeof _Bool certainly
satisfies).  The integer conversion rank of those extended types
would be unusual in that it would be less than the integer
conversion rank of _Bool, but the Standard doesn't preclude that
AFAICT.

Thus it appears that the answer to your question is Yes.