Compilation error Ubuntu 16.04

[grig-guz]

I get the following error (Ubuntu 16.04)

[  2%] Linking CXX executable ../../bin/shogun-unit-test
../../src/shogun/libshogun.so.18.0: error: undefined reference to 'google::protobuf::MessageFactory::InternalRegisterGeneratedFile(char const*, void (*)(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&))'
../../src/shogun/libshogun.so.18.0: error: undefined reference to 'google::protobuf::internal::AssignDescriptors(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, google::protobuf::internal::MigrationSchema const*, google::protobuf::Message const* const*, unsigned int const*, google::protobuf::MessageFactory*, google::protobuf::Metadata*, google::protobuf::EnumDescriptor const**, google::protobuf::ServiceDescriptor const**)'
../../src/shogun/libshogun.so.18.0: error: undefined reference to 'google::protobuf::Message::GetTypeName[abi:cxx11]() const'
../../src/shogun/libshogun.so.18.0: error: undefined reference to 'google::protobuf::Message::InitializationErrorString[abi:cxx11]() const'
CMakeFiles/shogun-unit-test.dir/io/MLDataHDF5File_unittest.cc.o:MLDataHDF5File_unittest.cc:function MLDataHDF5File_read_matrix_Test::TestBody(): warning: the use of `mktemp' is dangerous, better use `mkstemp' or `mkdtemp'
collect2: error: ld returned 1 exit status
tests/unit/CMakeFiles/shogun-unit-test.dir/build.make:6987: recipe for target 'bin/shogun-unit-test' failed
make[2]: *** [bin/shogun-unit-test] Error 1
CMakeFiles/Makefile2:505: recipe for target 'tests/unit/CMakeFiles/shogun-unit-test.dir/all' failed
make[1]: *** [tests/unit/CMakeFiles/shogun-unit-test.dir/all] Error 2
Makefile:160: recipe for target 'all' failed
make: *** [all] Error 2

How to fix that?

[grig-guz]

#3988 helped, successfully compiled after using -DENABLE_PROTOBUF=Offwith cmake.
Without this, I tried to reinstall protobuf, but still got the same error. How to fix it?

[karlnapf]

your protobuf setup is broken. You will need to investigate whether the library is in your dynamic linker path. The error is a standard error, so pls ask google. It could also be that shoguns cmake setup has to be fixed, in which case we can reopen this issue. Let me know

[grig-guz]

@karlnapf the problem was indeed my protobuf setup, thanks.