Hi, I have the following code (more or less ...) <snip> #include <boost/iostreams/filtering_stream.hpp> #include <boost/iostreams/filter/gzip.hpp> #include <boost/iostreams/copy.hpp> <snip> void function(...) { boost::iostreams::filtering_stream<boost::iostreams::input> inputfile; std::ifstream istream(fname.c_str(), std::ios_base::in | std::ios_base::binary); if (!istream) yamas::ioerror(fname); inputfile.push(boost::iostreams::gzip_decompressor()); inputfile.push(istream); <snip> std::string line; std::getline(inputfile, line); The code is compiling, yet when linking with gcc -o program -static trunk/src/file1.cpp trunk/src/file2.cpp ... -lboost_program_options -lboost_iostreams I get /usr/local/lib/libboost_iostreams.a(zlib.o): In function `boost::iostreams::detail::zlib_base::after(char const*&, char*&, bool)': zlib.cpp:(.text+0x120): undefined reference to `crc32' /usr/local/lib/libboost_iostreams.a(zlib.o): In function `boost::iostreams::detail::zlib_base::do_init(boost::iostreams::zlib_params const&, bool, void* (*)(void*, unsigned int, unsigned int), void (*)(void*, void*), void*)': zlib.cpp:(.text+0x77e): undefined reference to `inflateInit2_' zlib.cpp:(.text+0x7b7): undefined reference to `deflateInit2_' /usr/local/lib/libboost_iostreams.a(zlib.o): In function `boost::iostreams::detail::zlib_base::reset(bool, bool)': zlib.cpp:(.text+0x2d): undefined reference to `deflateReset' zlib.cpp:(.text+0x49): undefined reference to `inflateEnd' zlib.cpp:(.text+0x51): undefined reference to `inflateReset' zlib.cpp:(.text+0x59): undefined reference to `deflateEnd' /usr/local/lib/libboost_iostreams.a(zlib.o): In function `boost::iostreams::detail::zlib_base::xinflate(int)': zlib.cpp:(.text+0x64): undefined reference to `inflate' /usr/local/lib/libboost_iostreams.a(zlib.o): In function `boost::iostreams::detail::zlib_base::xdeflate(int)': zlib.cpp:(.text+0x74): undefined reference to `deflate' collect2: ld returned 1 exit status Any idea what's wrong? What I need to change? Christian PS I tried not to be too verbose, however, if any info is missing, please tell me.