Hi, I am using boost::iostreams in a project that I am currently working on. The relevant part of my code is shown below: #include <boost/iostreams/device/file_descriptor.hpp> #include <boost/iostreams/filtering_stream.hpp> #include <boost/iostreams/filter/gzip.hpp> ... void FileDataStore::write(DataSet *ds) { filtering_ostream os; // Check if we are writing a gzipped file int iext = this->filename.find_last_of('.'); if (iext != std::string::npos && this->filename.substr(iext+1) == "gz") { os.push(gzip_compressor()); } try { os.push(file_descriptor_sink(this->filename)); } catch (std::ios_base::failure e) { throw IOException() << errmsg_info((boost::format("Error opening file '%s': %s") % this->filename % strerror(errno)).str().c_str()); } // Write my stuff to os os.flush(); os.pop(); } Basically, if the filename being used ends in .gz I want the file written through a gzip filter so it is stored gzipped. The problem is: if I unzip the resulting file using gzip I get a message like this: gzip: myfile.gz: decompression OK, trailing garbage ignored The file content is OK but this message is annoying. What am I doing wrong that causes this? Many thanks, Regards // Mike