Hello, I'm trying to use the iostream libs using wstring, but I'm struggling with wstring. Her is my little piece of code: using namespace std; using namespace boost; struct Formatter { std::wstring operator() ( const match_results<const wchar_t*>& _Match ) { //TODO return wstring(); } }; int main(int argc, char** argv) { wstring File; //skipped steps to put data in wregex Regx(L"bla"); iostreams::wregex_filter Filter( Regx, Formatter() ); iostreams::filtering_wostream Out; Out.push( Filter ); Out.push( iostreams::wfile_sink("FilenameFormatted.txt") ); Out << File; } I'm using boost 1_34. If I compile this code vith vc80 express, I get an error: boost/iostreams/filter/aggregate.hpp(97) : error C2664: 'void boost::iostreams::aggregate_filter<Ch,Alloc>::do_write<Sink>(Sink &,const char *,std::streamsize)' : cannot convert parameter 2 from 'wchar_t *' to 'const char *' I'm a little lost :( Am I doing something wrong? Thank you very much for your help! pipoun