Hello, I use this code excerpt for copy file content: bio::stream< bio::basic_file_source<char> > l_file(p_str1); if (!l_file.is_open()) throw exception::runtime(_("file can not be opened")); std::copy( std::istream_iterator<char>(l_file), std::istream_iterator<char>(), std::ostreambuf_iterator<char>(&l_deflate) ); (*) l_file.close(); p_str1 is the filename and bio ist shorten for boost::iostreams, l_deflate is a bio::filtering_streambuf< bio::output > with a bzip2 compressor. I can set anything else to p_str1 (some not existing filesnames) and the code runs not into the if construction, the std::copy seems to copy any data, but which if there is no file under the stream !? The l_deflate is define with: bio::counter l_counter; bio::basic_null_sink<char> l_null; bio::filtering_streambuf< bio::output > l_deflate; l_deflate.push( bio::bzip2_compressor( m_bzip2param ) ); break; l_deflate.push( boost::ref(l_counter) ); l_deflate.push( l_null ); I would count the compressed bytes of a file (without writing the file), but I need to copy the filecontent without closing after copying, so I can't use boost::iostream::copy (it closes the streams after copy). On the (*) can be some other std::copy with other files Can anyone help me please to create a correct code ? Thanks a lot Phil