Re: External header guards

Hi Nikolai,

On Thursday 21 December 2006 13:17, Nikolai Pretzell wrote:

>  > The one remaining compiler is Microsoft Visual
>  > Studio. There are varying reports if this compiler has a build-in
>  > "include guard optimization" or not.
>
> According to Oliver Bolte, in version 8, the MSVC compiler uses the
> trick to connect a define (of an internal include guard) with the
> correlating header, which is one possble way to implement this,

Good news :-)

> but v.7 
> does not.
>
> Anyway, I would go with Thorstens remark: We will need years to remove
> the existing external include guards anyway. IMHO there is no
> significant performance gain by adding more of them now.

I hope that it won't be years.  The working script is here:

http://www.go-oo.org/ooo-build/bin/strip-guards

It removes the guards the safe way - just those that correspond with the 
header they are guarding.  I'm just running a test compilation (needs few 
hand fixes) now; when I'm done I'll give it Thorsten to test with MSVC 7.  If 
no big regression appears it could be a matter of one CWS ;-)

> So my
> Suggestion
> ----------
> is: From today on, we use internal include guards only.
> Until this has a measurable effect on our build times, we will use a
> newer version of MSVC.
>
> What do you think?

Sounds great :-)

Regards,
Jan