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"
> _______________________________________________
> Unsubscribe & other changes: http://listarchives.boost.org/mailman/listinfo.cgi/boost
>
>
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.