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From: Michal Nazarewicz <mina86@tlen.pl>
To: Rajat Jain <rajat.noida.india@gmail.com>
Cc: Linux Newbies <kernelnewbies@nl.linux.org>,
	newbie <linux-newbie@vger.kernel.org>
Subject: Re: strange code in linux kernel
Date: Wed, 07 Oct 2009 20:44:44 +0200	[thread overview]
Message-ID: <87pr8zm4bn.fsf@erwin.mina86.com> (raw)
In-Reply-To: <b115cb5f0910052034h5194a5t113a1bbcd9c878e3@mail.gmail.com> (Rajat Jain's message of "Tue, 6 Oct 2009 09:04:00 +0530")

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Rajat Jain <rajat.noida.india@gmail.com> writes:
> I found that there are some weird looking instances in kernel where a
> function has been DEFINED (as opposite to DECLARED) using and "extern"
> keyword. For e.g., the following code in arch/alpha/include/asm/io.h:
>
> extern inline void __iomem *generic_ioportmap(unsigned long a)
> {
>         return alpha_mv.mv_ioportmap(a);
> }
>
> Using a definition along with extern does not make any sense to me.
> Can some one please enlighten what is its use / purpose?

Note that at the same time an "inline" keyword has been used.  You might
want to refer to GCC's documentation in particular
<http://gcc.gnu.org/onlinedocs/gcc/Inline.html> for more information.
Google also pointed to this site
<http://www.greenend.org.uk/rjk/2003/03/inline.html> which also might
have some insight.

-- 
Best regards,                                         _     _
 .o. | Liege of Serenly Enlightened Majesty of      o' \,=./ `o
 ..o | Computer Science,  Michal "mina86" Nazarewicz   (o o)
 ooo +--<mina86*tlen.pl>--<jid:mina86*jabber.org>--ooO--(_)--Ooo--

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      reply	other threads:[~2009-10-07 18:44 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-06  3:34 strange code in linux kernel Rajat Jain
2009-10-07 18:44 ` Michal Nazarewicz [this message]

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