Hi, the following results in a compile error for msvc-10.0. It works for gcc-3.4, gcc-4.3, gcc-4.5. typedef mpl::vector_c<char, 'h','e','l','l','o',' ','w','o','r','l','d'> hello; typedef mpl::push_back<hello, mpl::char_<'!'> >::type hello2; BOOST_TEST((std::string(mpl::c_str<hello2>::value)== "hello world!")); // line 59 C:\cygwin\boost\v44\boost/mpl/string.hpp(592) : error C2039: 'value_type' : is not a member of 'boost::mpl::vector12<T0,T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11>' with [ T0=boost::mpl::integral_c<char,104>, T1=boost::mpl::integral_c<char,101>, T2=boost::mpl::integral_c<char,108>, T3=boost::mpl::integral_c<char,108>, T4=boost::mpl::integral_c<char,111>, T5=boost::mpl::integral_c<char,32>, T6=boost::mpl::integral_c<char,119>, T7=boost::mpl::integral_c<char,111>, T8=boost::mpl::integral_c<char,114>, T9=boost::mpl::integral_c<char,108>, T10=boost::mpl::integral_c<char,100>, T11=boost::mpl::char_<33> ] io\match_pass.cpp(59) : see reference to class template instantiation 'boost::mpl::c_str<Sequence>' being compiled with [ Sequence=hello2 ] Is this a known bug? Best, _____________________ Vicente Juan Botet Escribá http://viboes.blogspot.com/