Hello all, please help! I'm truly banging my head against the wall here. I am trying to write a function that will allow me to write gzipped binary files (~50 MB) and read them again. I have data in memory. Here's my code for writing: namespace io = boost::iostreams; filename = "c:/test.bin.gz"; //My output file int size = 5000000; //Data size in bytes, ~5 MB //Create filtering_ostream io::filtering_ostream out; //Creates a filtering_ostream called out out.push(io::gzip_compressor()); //Assigns the gzip_compressor to out out.push(io::file_sink(filename)); //Assigns a file sink to out char* memblock = new char [size]; //This is my data. In reality memblock will have been created earlier and filled with real data out.write(memblock, size); //Do the writing delete[] memblock; //Clean up As written above the resulting file, c:/test.bin.gz, is corrupt. If I try to decompress it, either with gzip or winrar, I get an error message. However, if I instead set size = 4000000 (~4 MB) (slightly smaller), the resulting file works just fine. My problem therefore is that my actual size is 50 MB... Please help! Anders (not a real programmer)