Date: Tue, 06 Sep 2005 13:55:26 -0700
From: Terrence Miller <Terrence.Miller@Sun.COM>
Subject: Re: [discuss] [2.6 patch] include/asm-x86_64 "extern inline" ->
 "static inline"
In-reply-to: <200509062223.50747.ak@suse.de>
To: Andi Kleen <ak@suse.de>
Cc: discuss@x86-64.org, Jakub Jelinek <jakub@redhat.com>,
       Adrian Bunk <bunk@stusta.de>, Michael Matz <matz@suse.de>,
       linux-kernel@vger.kernel.org
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Andi Kleen wrote:
> I don't think the functionality of having single copies in case 
> an out of line version was needed was ever required by the Linux kernel.

But shouldn't the compiler that compiles Linux be C99 compliant?

> extern inline was used in the kernel a long time ago as a "poor man's 
> -Winline". Basically the intention was to get an linker error 
> if the inlining didn't work for some reason because if we say
> inline we mean inline.
> 
> But that's long obsolete because the requirements of the C++ "template is 
> turing complete" people has broken inlining so badly (they want a lot of 
> inlining, but not too much inlining because otherwise their compile times 
> explode and the heuristics needed for making some of these pathologic cases 
> work seems to break a lot of other sane code)  that the kernel was forced to 
> define inline to __attribute__((always_inline)). And with that you get an 
> error if inlining
> fails. 
> 
> So the original purpose if extern inline is fulfilled by static inline now.
> However extern inline also doesn't hurt, it really makes no difference now.
> 
> -Andi
>  

-- 

                              Terrence

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        | Terrence C. Miller      |  Sun Microsystems      |
        | terrence.miller@Sun.COM |  M.S. MPK16-303        |
        | 650-786-9192            |  16 Network Circle     |
        |                         |  Menlo Park, CA 94025  |
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