When compiling Eigen 3.1.1 into a Visual Studio 2005 C++ project I get the following errors:

1>c:\m_lincs\3p\eigen\eigen\src/Core/PlainObjectBase.h(114) : error C2059: syntax error : 'string'
1> c:\m_lincs\3p\eigen\eigen\src/Core/PlainObjectBase.h(654) : see reference to class template instantiation 'Eigen::PlainObjectBase<Derived>' being compiled
1>c:\m_lincs\3p\eigen\eigen\src/Core/PlainObjectBase.h(114) : error C2091: function returns function
1>c:\m_lincs\3p\eigen\eigen\src/Core/PlainObjectBase.h(114) : error C2802: static member 'operator new' has no formal parameters
1>c:\m_lincs\3p\eigen\eigen\src/Core/PlainObjectBase.h(114) : error C2333: 'Eigen::PlainObjectBase<Derived>::operator new' : error in function declaration; skipping function body
1>c:\m_lincs\3p\eigen\eigen\src/Core/PlainObjectBase.h(114) : error C2059: syntax error : 'string'
1>c:\m_lincs\3p\eigen\eigen\src/Core/PlainObjectBase.h(114) : error C2090: function returns array

I get many more errors along the same lines for other header files, e.g. Geometry/Quaternion.h and Geometry/Transform.h, which I can post if necessary, I just don't want to confuse this initial post.

The errors occur under a debug configuration but not a release configuration.

This is the first post I've made and I'm not sure how much more detail is required so please let me know if I should put more detail in.

Thanks,

James.

Resolved by adding #define EIGEN_DONT_ALIGN.