conflict with Caffe(complied by gcc4.X), it confused me for a week !

[lyycfairy]

I had tried many ways to compile this project in Ubuntu14.04，but all failed at the last.
I have no idea about how to compile it.

face_swap needs gcc5.0+ for supporting C++11/14
but my Caffe was compiled by gcc4.X，protobuf2.5 was installed from apt-get
face_swap make failed when linking, about protobuf

Linking CXX executable face_swap_batch
_sequence_face_landmarks.pb.cc:(.text+0x48e): undefined reference to `google::protobuf::MessageFactory::InternalRegisterGeneratedFile(char const*, void (*)(std::__cxx11::basic_string<char, std::char_traits, std::allocator > const&))'

sequence_face_landmarks.pb.cc:(.text+0xdab): undefined reference to `google::protobuf::internal::WireFormatLite::WriteStringMaybeAliased(int, std::_cxx11::basic_string<char, std::char_traits, std::allocator > const&, google::protobuf::io::CodedOutputStream*)'

then, I tried to compile Caffe and Protobuf-2.5 with gcc5.5 from source
but Caffe was failed the same in linking

Linking CXX executable compute_image_mean
_compute_image_mean.cpp:(.text.startup+0x1bf): undefined reference to google::SetUsageMessage(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)' CMakeFiles/compute_image_mean.dir/compute_image_mean.cpp.o: In function std::__cxx11::basic_string<char, std::char_traits, std::allocator >* google::MakeCheckOpString<int, int>(int const&, int const&, char const*)':
compute_image_mean.cpp:(.text._ZN6google17MakeCheckOpStringIiiEEPNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEERKT_RKT0_PKc[_ZN6google17MakeCheckOpStringIiiEEPNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEERKT_RKT0_PKc]+0x43): undefined reference to google::base::CheckOpMessageBuilder::NewString[abi:cxx11]()' CMakeFiles/compute_image_mean.dir/compute_image_mean.cpp.o: In function std::_cxx11::basic_string<char, std::char_traits, std::allocator >* google::MakeCheckOpString<unsigned long, int>(unsigned long const&, int const&, char const*)':

I was very confused about how to choose the gcc version to avoid the conflict?

[YuvalNirkin]

Building this project and all it's dependencies is not easy I know.
First of all the minimum version of Protobuf as required by sequence_face_landmarks is 3.0.0.
I suggest you build all dependencies from source using CMake, make sure that you checkout stable releases and not the master branch (except for the face_swap project in which the master branch is preferable).

You can use the ldd command to understand where the linkage problems are coming from.

Good luck!