I also see the same problem compiling with 32 bit MSVC 7.1 SP1 (13.10.6030). I don't experience the issue when using STLport - only when using the native Dinkumware STL implementation (not surprising given the preprocessor directives in the file). src\usinstances.cpp(47) : error C2910: 'std::char_traits<wchar_t>::length' : cannot be explicitly specialized I tried grabbing the latest copy of the source file from SVN, but it appears identical to that included in the 1.37.0 distribution. I haven't tried updating all the source and headers for the entire regex component yet... Gary -- View this message in context: http://www.nabble.com/Compiling-64bit-regex-1.37.0-with-VS2005-tp20493076p20... Sent from the Boost - Dev mailing list archive at Nabble.com.