linux-kernel - Re: how does 0x##p##q work

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Message-ID: <55B26EAA.70209@infradead.org>
Date:	Fri, 24 Jul 2015 09:58:18 -0700
From:	Randy Dunlap <rdunlap@...radead.org>
To:	Ahmed Soliman <ahmedsoliman0x666@...il.com>,
	linux-kernel@...r.kernel.org
Subject: Re: how does 0x##p##q work

On 07/24/15 09:02, Ahmed Soliman wrote:
> I was working on cleaning up some files in the crypto dirctory using
> checkpatch.pl
> and I found this strange define in crypto/gf128mul.c
> #define xx(p, q) 0x##p##q
> It just seems really weird macro and I cant figure out what is it
> supposed to do!!

## is defined in any complete C language spec (it's a preprocessor directive).

It is used for string concatenation, aka pasting or gluing strings together.

google can find lots of references for it if you need more info.

-- 
~Randy
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