Re: [boost] [#pragma once]

Subject: Re: [boost] [#pragma once]
From: Marcus Lindblom (macke_at_[hidden])
Date: 2009-04-10 11:23:31

Edouard A. wrote:
>> Each one of them supports #pragma once.  Is there any reason to wrap
>> this pragma within #ifdefs? Are there any compilers out there today
>> that
>> don't support this #pragma?
> 
>> Could we change this coding pattern so that it no longer looks like
>> MSVC
>> is being selfish?
>>
> [Edouard A.] 
> 
> In addition #pragma once may be faster than #ifndef/#endif because the
> compiler is not even going to open the file a second time to parse the
> #ifndef/#endif.

I've seen benchmarks that say some compilers (gcc, msvc) are smart 
enough to recognize #ifndef/#endif and do the #pragma once equivalent. 
(i.e. there's no discernable performance difference.)

Can't find the link now though.. :(

Cheers,
/Marcus