Re: [boost] Proposal for #pragma once support

Subject: Re: [boost] Proposal for #pragma once support
From: Maik Beckmann (beckmann.maik_at_[hidden])
Date: 2009-06-09 15:23:27

Emil Dotchevski schrieb am Dienstag 09 Juni 2009 um 21:00:
> On Tue, Jun 9, 2009 at 11:19 AM, Zachary Turner <divisortheory_at_[hidden]> 
wrote:
> > #if defined(_MSC_VER) && (_MSC_VER >= 1020)
> > #pragma once
> > #endif
> >
> > That's all it takes.  Everybody benefits.
>
> I'm sorry but what problem are we trying to solve with this? Does
> compiling Boost take too much time? If the answer is yes, is #pragrma
> once the best solution we can come up with? :)

While having no experience with "#pragma once", my impression is that it has 
an positive effect if the filesystem is slow when touching many small files, 
which I painfully experience on MS.Windows (at least on XP, dunno if Vista and 
Windows7 suffer from this as well).  

The point of Zachary's approach is being a non intrusive no brainer solution.  
All the user has to do is to add a definition to the command line via his/her 
build system.  

Well, given that there is an measurable effect on real boost using code.  I 
suggest we wait until Zachary wrote the script and did benchmarks on some of 
the plenty files at the libs test dirs.

-- Maik