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         U __cxa_guard_acquire@@CXXABI_1.3
         U __cxa_guard_release@@CXXABI_1.3
         U __cxa_pure_virtual@@CXXABI_1.3
         w __gmon_start__
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$ g++ -pthread -lboost_system -o bitgreed bencode.o boost.asio.o corrupted_hash.o file_entry.o little_endian.o main.o message.o metainfo.o missing_key.o peer_client.o peer_info.o query_string.o sha1.o sha1_hash.o tracker_client.o tracker_response.o util.o wrong_key_type.o
boost.asio.o: In function `error_code':
/usr/local/include/boost/system/error_code.hpp:315: undefined reference to `boost::system::system_category()'
boost.asio.o: In function `boost::asio::error::get_system_category()':
/usr/local/include/boost/asio/error.hpp:216: undefined reference to `boost::system::system_category()'
metainfo.o: In function `greed::get_trackers(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&)':
/home/martinho/dev/bitgreed/metainfo.cpp:36: undefined reference to `boost::optional<std::vector<greed::bvalue, std::allocator<greed::bvalue> > > greed::opt<std::vector<greed::bvalue, std::allocator<greed::bvalue> > >(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
metainfo.o: In function `metainfo':
/home/martinho/dev/bitgreed/metainfo.cpp:87: undefined reference to `boost::optional<long long> greed::opt<long long>(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
/home/martinho/dev/bitgreed/metainfo.cpp:87: undefined reference to `boost::optional<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > greed::opt<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
/home/martinho/dev/bitgreed/metainfo.cpp:87: undefined reference to `boost::optional<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > greed::opt<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
/home/martinho/dev/bitgreed/metainfo.cpp:87: undefined reference to `boost::optional<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > greed::opt<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
metainfo.o: In function `boost::optional<long long> const greed::info_opt<long long>(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)':
/home/martinho/dev/bitgreed/metainfo.cpp:29: undefined reference to `boost::optional<long long> greed::opt<long long>(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
tracker_response.o: In function `greed::get_value(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&)':
/home/martinho/dev/bitgreed/tracker_response.cpp:70: undefined reference to `boost::optional<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > greed::opt<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
/home/martinho/dev/bitgreed/tracker_response.cpp:73: undefined reference to `boost::optional<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > greed::opt<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
/home/martinho/dev/bitgreed/tracker_response.cpp:75: undefined reference to `boost::optional<long long> greed::opt<long long>(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
/home/martinho/dev/bitgreed/tracker_response.cpp:76: undefined reference to `boost::optional<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > greed::opt<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, greed::bvalue, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, greed::bvalue> > > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)'
collect2: ld returned 1 exit status
make: *** [bitgreed] Error 1