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From: David Laight <David.Laight@ACULAB.COM>
To: 'Kees Cook' <keescook@chromium.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"'linux@rasmusvillemoes.dk'" <linux@rasmusvillemoes.dk>,
	'Steven Rostedt' <rostedt@goodmis.org>,
	"'bvanassche@acm.org'" <bvanassche@acm.org>,
	"torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
	"Nathan Chancellor" <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Arnd Bergmann <arnd@arndb.de>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>
Subject: RE: [PATCH v2 next] compiler.h: Move __is_constexpr() to compiler.h.
Date: Fri, 6 Oct 2023 15:51:06 +0000	[thread overview]
Message-ID: <321c3c0984e64e9cbd1b034755611710@AcuMS.aculab.com> (raw)
In-Reply-To: <202310050921.F0B15702D4@keescook>

It can also be defined more portably as:

#define __is_constexpr(x) \
	_Generic(0 ? (void *)((long)(x) * 0) : (int *)0, int *: 1, void *: 0)

Which doesn't rely on 'sizeof (void)' being valid.

But that is for another day.

There is also:
#define is_pointer_type(type) __is_constexpr((type)1)

	David

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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)


      parent reply	other threads:[~2023-10-06 15:51 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-05 11:39 David Laight
2023-10-05 16:21 ` Kees Cook
2023-10-06  8:28   ` David Laight
2023-10-06 15:51   ` David Laight [this message]

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