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Subject: Re: [RFC] Add stdckdint.h header for C23
From: Martin Uecker <uecker@tugraz.at>
To: jakub@redhat.com
Cc: gcc-patches@gcc.gnu.org
Date: Sun, 11 Jun 2023 16:05:03 +0200
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Hi Jakup,

two comments which may or may not be helpful:

Clang extended _Generic in a similar way:
https://github.com/llvm/llvm-project/commit/12728e144994efe84715f4e5dbb8c3104e9f0b5a

Although for _Generic you can achieve the same with checking
for compatiblilty of pointer to the type, and I do not think
this helps with the classification problem.


If I am not missing something, you should be able to check
for an enumerated type using _Generic by checking that the
type is not compatible to another enum type:

enum type_check { _X = 1 };

#define type_is_enum(x) \
    _Generic(x, unsigned int: _Generic(x, enum type_check: 0, default: 1), default: 0)

https://godbolt.org/z/j6z4a4Mdn

For C23 with fixed underlying type this may become more
complicated. Maybe this becomes to messy.

Martin