Re: [boost] [array] Invalid data: accessing 'elems'

Subject: Re: [boost] [array] Invalid data: accessing 'elems'
From: Mateusz Loskot (mateusz_at_[hidden])
Date: 2010-09-04 14:52:55

On 04/08/10 08:51, Niels Dekker - address until 2010-10-10 wrote:
> On 2010-08-02-Mon 18:29, Mateusz Loskot wrote:
>>
>> Shall I report a ticket?
> 
> Do you have a proposed fix?

Actually, I'm asking for suggestions :-)

> I can think of a few possible options:
> 
> * Add #pragma warning(disable: 6385) to boost/array.hpp
> 
> * Or add an __analysis_assume call to boost::array::operator[]:
> 
>   reference operator[](size_type i)
>   {
>      BOOST_ASSERT( i < N && "out of range" );
>      __analysis_assume(i < N);
>      return elems[i];
>   }
> 
> * Or add __analysis_assume(expr) to the BOOST_ASSERT(expr) macro
> itself... (boost/assert.hpp)?
> 
> What do you think?

I'd second the first or the second option as they are more explicit,
thus self-documenting.
The third option would hide this issue behind BOOST_ASSERT.

> BTW, the following compiler bug report seems related: Microsoft Visual
> Studio bug report ID 281033, "False warning C6385 when a function result
> is used as an array index",
> http://connect.microsoft.com/VisualStudio/feedback/details/281033/

Thanks.

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org