I'm compiling the Boost 1.36.0 Math library for Windows Mobile 5 using Visual Studio 2008. I have STLPort-5.1.5 installed. When I get to anything requiring errno support, I get compiler errors as below: compile-c-c++ bin.v2\libs\math\build\msvc-WM5\debug\link-static\runtime-link-static\stdlib-stlport\threading-multi\acosh.obj acosh.cpp Unknown EVC++ compiler version - please run the configure tests and report the results eMbedded Visual C++ 3 and .NET don't have a errno.h header; STLport won't include native errno.h here C:\boost\boost_1_36_0\boost/math/policies/error_handling.hpp(149) : error C2065: 'errno_t' : undeclared identifier [...] C:\boost\boost_1_36_0\boost/math/policies/error_handling.hpp(149) : error C2065: 'EDOM' : undeclared identifier [..] C:\boost\boost_1_36_0\boost/math/policies/error_handling.hpp(233) : error C2065: 'ERANGE' : undeclared identifier In the STLPort errno.h header, there's a section: #ifdef _STLP_WCE // only show message when directly including this file in a non-library build # if !defined(__BUILDING_STLPORT) && (_STLP_OUTERMOST_HEADER_ID == 0x205) # pragma message("eMbedded Visual C++ 3 and .NET don't have a errno.h header; STLport won't include native errno.h here") #define errno errno_t I can add an "#include<crtdefs.h>" to get errno_t support, but that just declares it as "typedef int errno_t;". Which, of course, gives me " boost/math/policies/error_handling.hpp(149) : error C2513: 'int' : no variable declared before '=' " errors as that isn't the way Boost expects to be able to use errno. What can I do to either get errno support under CE or remove the dependency of that feature without breaking Boost? Thanks, PaulH