Re: [boost] [xpressive] Performance Tuning?

Subject: Re: [boost] [xpressive] Performance Tuning?
From: Raindog (raindog_at_[hidden])
Date: 2009-07-21 16:35:33

Celtic Minstrel wrote:
> On Tue, Jul 21, 2009 at 6:17 AM, Edward Grace<ej.grace_at_[hidden]> wrote:
> >  // Will the following fail? It jolly well should!
> >  v[5]  = 2;
> >  cout << v.capacity() << " " << v.size() << endl;
>
> > That's pure evil of course! I suppose that's a good reason for always using
> > .begin() and .end() rather than .begin() + N.
>
> Correct me if I'm wrong, but it seems you're complaining that v[5]
> doesn't do bounds checking?
> The standard does not require bounds checking on array subscript,
> though it seems there's
> nothing saying it shouldn't bounds check. But there's the alternate
> v.at(5) notation if you do need
> bounds checking.
>
> --SPCD
> "Celtic Minstrel"
> _______________________________________________
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>
>   
The issue is that v.begin(), v.begin()+5 should not be bounds checked, 
but by default in vc9 (vs 2008) it is. In vc10, the default is that it 
is not on by default.