2013-03-14 12:16:32 -0500 commented question Compilation failure in VS2010 (Error C2891) OK - FWIW I got it working. I was bringing over some Qt code and there were some header files included in the chain. Turns out, by changing the order of inclusion, it compiles fine, e.g. OpenCV then Qt is fine, but Qt then OpenCV gave me the above error. Some clobbering of 'size_t'? Sorry for any confusion - I never suspected this, since the exact same code worked fine on Linux, OSX, and Windows with mingw. Just under VS did this pop up. Sigh. 2013-03-11 11:40:15 -0500 commented question Compilation failure in VS2010 (Error C2891) I agree that they don't make any sense, but the only offending line of code is #include <core/core.hpp>  As far as I can tell, it never gets past parsing the OpenCV header file 'core.hpp', failing with the error noted above (C2891). I'll post if I can track down a solution. FWIW: VS 2010, Win7 64 bit, pre-built binaries for OpenCV TIA B 2013-03-08 13:28:09 -0500 asked a question Compilation failure in VS2010 (Error C2891) Hey all, I'm trying to build a simple OpenCV (v2.4.4) program with Visual Studio 2010 and encountering an issue that I've never seen with OpenCV under linux. I suspect it's a MS vs gcc thing, but here's the error I get (keep in mind this worked fine before under linux - only the compiler is different): C:\Program Files\opencv\build\include\opencv2/core/core.hpp(3142): error C2891: 'fixed_size' : cannot take the address of a template parameter C:\Program Files\opencv\build\include\opencv2/core/core.hpp(3114) : see declaration of 'fixed_size' C:\Program Files\opencv\build\include\opencv2/core/core.hpp(3143) : see reference to class template instantiation 'cv::AutoBuffer<_Tp,fixed_size>' being compiled I'm a stranger in a strange Windows land, so any advice is appreciated. I may try reverting to a 2.3.x version of OpenCV, but I had some dim hope that there was an easy fix and I was just missing something obvious; C++ template programming isn't my favorite thing. Thanks in advance, Bill U