Hello. I've been experiencing the following problem with the gzip_compressor filter: It always writes data down the stream, regardless if any data has been written to the filtering_stream. Consider the following program: -------------------------------------------------------- #include <iostream> #include <fstream> #include <boost/iostreams/filtering_stream.hpp> #include <boost/iostreams/filter/gzip.hpp> using namespace std; using namespace boost; int main() { ofstream file; file.open("hello.gz", ios_base::out | ios_base::app | ios_base::binary); iostreams::filtering_stream<boost::iostreams::output> stream; stream.push(iostreams::gzip_compressor()); stream.push(file); return 0; } -------------------------------------------------------- If compiled as "test", the following behavior is observed: $ ./test; ls -l hello.gz -rw-r--r-- 1 count0 users 8 2005-10-30 19:51 hello.gz $ ./test; ls -l hello.gz -rw-r--r-- 1 count0 users 16 2005-10-30 19:51 hello.gz $ ./test; ls -l hello.gz -rw-r--r-- 1 count0 users 24 2005-10-30 19:51 hello.gz That is, it always adds 8 bytes to the file, despite the fact that nothing was written to the stream. To top things off, the data inside the file isn't even recognizable by gzip: $ gunzip hello.gz gunzip: hello.gz: not in gzip format When bzip2_compressor is used, this strange behavior doesn't happen, and the file remains with 0 bytes. I guess this is a bug, right? I'm using boost 1.33.0 with GCC 4.0.1 in a GNU/Linux system. Thanks for any help. -- Tiago de Paula Peixoto <tiago@forked.de>