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MSVC std::vector and aligned data

yckx · 2011-11-05T15:52:31

I switched to the DirectXMath library when I switched to D3D11, and I'm running into this issue of Microsoft's std::vector implementation being incompatible with aligned data types. Looking around the 'Net it looks like the standard fixes are to avoid using std::vector, use a custom allocator, patch [s]vector::rebind[/s] vector::resize to take a const reference, or a combination of the latter two measures. But all the relevant pages I found were from 2008 or older. So, what does the GD.net community suggest? And does anyone have a custom aligned allocator, or do I need to learn to write my own?

General and Gameplay Programming Programming Unity

Started by yckx October 04, 2011 02:12 AM

21 comments, last by mrbastard 12 years, 6 months ago

yckx

1,298

Author

October 06, 2011 07:12 AM

FWIW, I decided to use btAlignedObjectArray; learning to write a custom allocator is a task for another day. I'm still fairly new to the use of aligned memory and whatever eases the curve is a short-term win.

Rattrap

3,386

November 05, 2011 02:56 PM

After reading this thread back in October, I had submitted a bug report to Microsoft about vector resize not taking a const reference. Some research had shown that it had been previously requested to be changed to a const reference, but it had been rejected to be fixed.

As you can see by the first link, this wll be fixed in VC11.

Hi,

Thanks for reporting this bug. We've fixed it, and the fix will be available in VC11.

Amusingly, when this was originally reported in July 2006 (months before I joined the VC team), this was indeed By Design. C++03 23.2.4.2 [lib.vector.capacity]/6 specified:

void resize(size_type sz, T c = T());

Now, C++11 23.3.6.3 [vector.capacity]/9, 11 specifies:

void resize(size_type sz);
void resize(size_type sz, const T& c);

This change was introduced in March 2008's Working Paper N2588.

If you have any further questions, feel free to E-mail me at stl@microsoft.com .

Stephan T. Lavavej
Visual C++ Libraries Developer
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