linux-kernel - RE: [PATCH 1/2] selftests: Provide local define of min() and max()

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Message-ID: <956ab0e63b8340669c31d2452830b7f3@AcuMS.aculab.com>
Date:   Thu, 24 Aug 2023 08:53:25 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Mahmoud Matook' <mahmoudmatook.mm@...il.com>
CC:     'Willem de Bruijn' <willemdebruijn.kernel@...il.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "pabeni@...hat.com" <pabeni@...hat.com>,
        "edumazet@...gle.com" <edumazet@...gle.com>,
        "shuah@...nel.org" <shuah@...nel.org>,
        "linux-kernel-mentees@...ts.linuxfoundation.org" 
        <linux-kernel-mentees@...ts.linuxfoundation.org>
Subject: RE: [PATCH 1/2] selftests: Provide local define of min() and max()

From: Mahmoud Matook
> Sent: Wednesday, August 23, 2023 8:36 PM
...
> I tried to use the relaxed version provided in the shared patchset link
> besides not able to use is_constexpr(), I'm not able to use
> __UNIQUE_ID() also. It's definded inside include/linux/compiler-gcc.h
> and it uses another macro __PASTE() which is defined inside
> include/linux/compiler_types.h.
> not sure what to do next
>
> - bring those macros definitions to able to use the relaxed version.
> - if the most important point for min/max defines inside selftests is to
>   avoid multiple evaluation is the below version acceptable?
>
>   #define min(x, y) ({ \
>     typeof(x) _x = (x); \
>     typeof(y) _y = (y); \
>     _x < _y ? _x : _y; \
> })
> 
> #define max(x, y) ({ \
>     typeof(x) _x = (x); \
>     typeof(y) _y = (y); \
>     _x > _y ? _x : _y; \
> })

Those are a reasonable pair.

If you want a signed-ness check the:
	_Static_assert(is_signed_type(typeof(a)) == is_signed_type(typeof(b)), "min/max signednesss")
check should just drop into the above.

	David

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