I have a problem with boost 1.34.1 (filesystem::ofstream and format). Compiler Vc71 and vc80 Is this is a bug or my mistake. Zdravko Code: #include <boost/format.hpp> #include <boost/filesystem/fstream.hpp> #include <boost/filesystem.hpp> void test () { boost::filesystem::ofstream os (boost::filesystem::path ("foo.out")); os << boost::format("%s\n") % "foo.text"; } Vc80 output: c:\projects\boost_test\test.cpp(8) : error C2593: 'operator <<' is ambiguous d:\libs\cpp\boost\1.34.1\boost\boost\filesystem\path.hpp(617): could be 'std::basic_ostream<_Elem,_Traits> &boost::filesystem::operator <<<boost::basic_format<Ch>>(std::basic_ostream<_Elem,_Traits> &,const Path &)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char>, Ch=char, Path=boost::basic_format<char> ] d:\libs\cpp\boost\1.34.1\boost\boost\format\free_funcs.hpp(33): or 'std::basic_ostream<_Elem,_Traits> &boost::operator <<<char,std::char_traits<char>,std::allocator<_Ty>>(std::basic_ostream<_Elem,_Traits> &,const boost::basic_format<Ch> &)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char>, _Ty=char, Ch=char ] while trying to match the argument list '(boost::filesystem::ofstream, boost::basic_format<Ch>)' with [ Ch=char ]