If I have a vc7.1 source file with nothing but: #include "stdafx.h" #include <boost/bind.hpp> #include <boost/variant.hpp> I get the following errors: c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\boost\mpl\less.hpp(39) : error C2760: syntax error : expected ',' not ';' c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\boost\mpl\less.hpp(51) : see reference to class template instantiation 'boost::mpl::less<T1,T2>' being compiled c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\boost\mpl\less.hpp(39) : error C2144: syntax error : 'const bool' should be preceded by '}' c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\boost\mpl\less.hpp(39) : error C2062: type 'const bool' unexpected c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\boost\mpl\less.hpp(39) : error C2238: unexpected token(s) preceding ';' c:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\include\boost\mpl\less.hpp(42) : error C2065: 'value' : undeclared identifier The problems go away if I include variant.hpp first. Any ideas? Thanks, Brock