I'm just making my way through finishing the boost http server project, which was written in visual studio using msvc compiler. All went well until I started porting this to linux. Here's a linking error displayed in console
http_server.cpp:(.text+0x995): undefined reference to `vtable for boost::detail::thread_data_base'
/usr/bin/ld: http_server.cpp:(.text+0xa05): undefined reference to `pthread_condattr_setclock'
/usr/bin/ld: http_server.cpp:(.text+0xb83): undefined reference to `boost::thread::start_thread_noexcept()'
/usr/bin/ld: http_server.cpp:(.text+0xc69): undefined reference to `boost::thread::native_handle()'
/usr/bin/ld: http_server.cpp:(.text+0xc82): undefined reference to `boost::thread::join_noexcept()'
/usr/bin/ld: /tmp/ccFIQ0RA.o: in function `boost::detail::thread_data<boost::_bi::bind_t<unsigned long, boost::_mfi::mf0<unsigned long, boost::asio::io_context>, boost::_bi::list1<boost::_bi::value<boost::asio::io_context*> > > >::~thread_data()':
Here's my Makefile
STANDARD = c++11
LIBPATH=/usr/lib/x86_64-linux-gnu
LINUX_THREAD=-lpthread
BOOST_THREAD=/usr/lib/x86_64-linux-gnu/libboost_thread.a
OUTPUT=cppserver
build_gcc:
g++ -O2 -std=$(STANDARD) $(LINUX_THREAD) -o $(OUTPUT) CppServer/servers/http_server/http_server.cpp ;\
CppServer/servers/http_server/connection.cpp CppServer/core/app.cpp CppServer/core/dbconn.cpp ;\
CppServer/servers/http_server/response.cpp CppServer/servers/http_server/request.cpp ;\
CppServer/math_unit.cpp CppServer/main.cpp $(BOOST_THREAD) -L$(LIBPATH)
I also tried to set BOOST_THREAD to 'boost_thread', but it failed as well.
Any ideas?
Related
I have a large codebase with multiple files and multiple Cmake files as well. The structure is src/folder1 src/folder2 etc and I run catkin_make -j1 from the src directory level. I am unable to link MKL. A small clip of the error is
/usr/bin/ld: /opt/intel/oneapi/mkl/2021.3.0/lib/intel64/libmkl_intel_thread.so: undefined reference to `mkl_sparse_d_xESB_SpMV_8_i4'
/usr/bin/ld: /opt/intel/oneapi/mkl/2021.3.0/lib/intel64/libmkl_intel_thread.so: undefined reference to `mkl_spblas_zcoo0ssunc__mmout_par'
/usr/bin/ld: /opt/intel/oneapi/mkl/2021.3.0/lib/intel64/libmkl_intel_thread.so: undefined reference to `mkl_spblas_zcoo1ntuuf__mmout_par'
/usr/bin/ld: /opt/intel/oneapi/mkl/2021.3.0/lib/intel64/libmkl_intel_thread.so: undefined reference to `mkl_spblas_lp64_scsr0ntunc__smout_par'
/usr/bin/ld: /opt/intel/oneapi/mkl/2021.3.0/lib/intel64/libmkl_intel_thread.so: undefined reference to `mkl_spblas_lp64_ccsr0nd_nc__svout_seq'
/usr/bin/ld: /opt/intel/oneapi/mkl/2021.3.0/lib/intel64/libmkl_intel_thread.so: undefined reference to `mkl_spblas_ccoo1stlnf__svout_seq'
/usr/bin/ld: /opt/intel/oneapi/mkl/2021.3.0/lib/intel64/libmkl_intel_thread.so: undefined reference to `mkl_pds_pds_her_pos_fwd_ker_seq_nrhs_cmplx'
collect2: error: ld returned 1 exit status
I even added the following line to each cmake:
SET(GCC_COVERAGE_LINK_FLAGS " -L${MKLROOT}/lib/intel64 -Wl,--no-as-needed -lmkl_intel_ilp64 -lmkl_gnu_thread -lmkl_core -lgomp -lpthread -lm -ldl")
The code does not use MKL BLAS directly but rather it is used by libraries like Opencv and Eigen (OpenCV was built with MKL).
I do define EIGEN_USE_MKL_ALL.
How do I link MKL?
You can make use of oneMKL link line advisor which recommends what are the required libraries and necessary compiler options for the use case on which you are working.
Here is the link
https://software.intel.com/content/www/us/en/develop/tools/oneapi/components/onemkl/link-line-advisor.html
I used the python amalmagate file to compile the json library. Now when I run the c++ code, I keep getting this error.
/usr/bin/ld: msort.cc:(.text+0x255): undefined reference to Json::Value::~Value()' /usr/bin/ld: msort.cc:(.text+0x264): undefined reference to Json::Value::~Value()'
/usr/bin/ld: msort.cc:(.text+0x278): undefined reference to Json::Value::operator[](int)' /usr/bin/ld: msort.cc:(.text+0x28c): undefined reference to Json::Value::Value(char const*)'
/usr/bin/ld: msort.cc:(.text+0x2a7): undefined reference to `Json::Value::get(char const*, Json::Value const&) const'
This is what I used to download the jsoncpp library
git clone https://github.com/open-source-parsers/jsoncpp.git
cd jsoncpp
python amalgamate.py
The code I ran to compile: g++ msort.cc -o msort
I understand that this means that the library is not connecting with my code. Any idea how I can fix this?
If you read the instructions for the amalgamated library you will see that you need to build with the library source file dist/jsoncpp.cpp:
g++ msort.cc dist/jsoncpp.cpp -o msort
I am fairly new to using Linux. But I believe I have done the correct steps to get set up:
wget for Python 3.8.5, did the make for it.
wget for boost 1.74, bootstrap, ./b2
And boost installed and setup everything except for Python which it did not auto-detect. After many hours of frustration, I can get it to find python with:
./bootstrap.sh --with-python=python3.8
running ./b2 --debug-configuration --with-python
shows that it has found it here:
notice: [python-cfg] Details of this Python configuration: notice:
[python-cfg] interpreter command: "/usr/local/bin/python3.8" notice:
[python-cfg] include path: "/usr/local/include/python3.8" notice:
[python-cfg] library path: "/usr/local/lib/python3.8/config"
"/usr/local/lib"
So to this end I am compiling my program successfully with the boost include and python include folder mentioned from b2's debug output above. I am linking similarly with -lpython3.8 -lboost_python38 -lboost_system
All 3 are being found evidently as it does not complain about missing libraries.
Parser.o: In function `_Py_DECREF':
Parser.cpp:(.text+0x5b): undefined reference to `_Py_Dealloc'
Parser.o: In function `sections_to_html(std::__cxx11::list<DivSection, std::allocator<DivSection> > const&)':
Parser.cpp:(.text+0x1eb3): undefined reference to `PyUnicode_FromString'
Parser.cpp:(.text+0x1edf): undefined reference to `PyUnicode_FromString'
Parser.o: In function `PyInit_Parser':
Parser.cpp:(.text+0x245b): undefined reference to `boost::python::detail::init_module(PyModuleDef&, void (*)())'
Parser.o: In function `boost::python::type_info::name() const':
Parser.cpp:(.text._ZNK5boost6python9type_info4nameEv[_ZNK5boost6python9type_info4nameEv]+0x1f): undefined reference to `boost::python::detail::gcc_demangle(char const*)'
Parser.o: In function `boost::python::api::object::object()':
Parser.cpp:(.text._ZN5boost6python3api6objectC2Ev[_ZN5boost6python3api6objectC5Ev]+0x14): undefined reference to `_Py_NoneStruct'
Parser.o: In function `_object* boost::python::expect_non_null<_object>(_object*)':
Parser.cpp:(.text._ZN5boost6python15expect_non_nullI7_objectEEPT_S4_[_ZN5boost6python15expect_non_nullI7_objectEEPT_S4_]+0x14): undefined reference to `boost::python::throw_error_already_set()'
Parser.o: In function `boost::python::tuple boost::python::make_tuple<boost::python::handle<_object>, boost::python::handle<_object> >(boost::python::handle<_object> const&, boost::python::handle<_object> const&)':
Parser.cpp:(.text._ZN5boost6python10make_tupleINS0_6handleI7_objectEES4_EENS0_5tupleERKT_RKT0_[_ZN5boost6python10make_tupleINS0_6handleI7_objectEES4_EENS0_5tupleERKT_RKT0_]+0x2c): undefined reference to `PyTuple_New'
Parser.cpp:(.text._ZN5boost6python10make_tupleINS0_6handleI7_objectEES4_EENS0_5tupleERKT_RKT0_[_ZN5boost6python10make_tupleINS0_6handleI7_objectEES4_EENS0_5tupleERKT_RKT0_]+0x51): undefined reference to `boost::python::api::object::object(boost::python::handle<_object> const&)'
Parser.cpp:(.text._ZN5boost6python10make_tupleINS0_6handleI7_objectEES4_EENS0_5tupleERKT_RKT0_[_ZN5boost6python10make_tupleINS0_6handleI7_objectEES4_EENS0_5tupleERKT_RKT0_]+0xda): undefined reference to `boost::python::api::object::object(boost::python::handle<_object> const&)'
Parser.o: In function `void boost::python::def<boost::python::tuple (*)(char const*)>(char const*, boost::python::tuple (*)(char const*))':
Parser.cpp:(.text._ZN5boost6python3defIPFNS0_5tupleEPKcEEEvS4_T_[_ZN5boost6python3defIPFNS0_5tupleEPKcEEEvS4_T_]+0x50): undefined reference to `boost::python::detail::scope_setattr_doc(char const*, boost::python::api::object const&, char const*)'
Parser.o: In function `boost::python::api::object boost::python::detail::make_function_aux<boost::python::tuple (*)(char const*), boost::python::default_call_policies, boost::mpl::vector2<boost::python::tuple, char const*> >(boost::python::tuple (*)(char const*), boost::python::default_call_policies const&, boost::mpl::vector2<boost::python::tuple, char const*> const&)':
Parser.cpp:(.text._ZN5boost6python6detail17make_function_auxIPFNS0_5tupleEPKcENS0_21default_call_policiesENS_3mpl7vector2IS3_S5_EEEENS0_3api6objectET_RKT0_RKT1_ [_ZN5boost6python6detail17make_function_auxIPFNS0_5tupleEPKcENS0_21default_call_policiesENS_3mpl7vector2IS3_S5_EEEENS0_3api6objectET_RKT0_RKT1_]+0x67): undefined reference to `boost::python::objects::function_object(boost::python::objects::py_function const&)'
Parser.o: In function `boost::python::objects::py_function_impl_base::py_function_impl_base()':
Parser.cpp:(.text._ZN5boost6python7objects21py_function_impl_baseC2Ev[_ZN5boost6python7objects21py_function_impl_baseC5Ev]+0xb): undefined reference to `vtable for boost::python::objects::py_function_impl_base'
Parser.o:(.data.rel.ro._ZTVN5boost6python7objects23caller_py_function_implINS0_6detail6callerIPFNS0_5tupleEPKcENS0_21default_call_policiesENS_3mpl7vector2IS5_S7_EEEEEE [_ZTVN5boost6python7objects23caller_py_function_implINS0_6detail6callerIPFNS0_5tupleEPKcENS0_21default_call_policiesENS_3mpl7vector2IS5_S7_EEEEEE]+0x30): undefined reference to `boost::python::objects::py_function_impl_base::max_arity() const'
Parser.o: In function `boost::python::objects::caller_py_function_impl<boost::python::detail::caller<boost::python::tuple (*)(char const*), boost::python::default_call_policies, boost::mpl::vector2<boost::python::tuple, char const*> > >::~caller_py_function_impl()':
Parser.cpp:(.text._ZN5boost6python7objects23caller_py_function_implINS0_6detail6callerIPFNS0_5tupleEPKcENS0_21default_call_policiesENS_3mpl7vector2IS5_S7_EEEEED2Ev [_ZN5boost6python7objects23caller_py_function_implINS0_6detail6callerIPFNS0_5tupleEPKcENS0_21default_call_policiesENS_3mpl7vector2IS5_S7_EEEEED5Ev]+0x22): undefined reference to `boost::python::objects::py_function_impl_base::~py_function_impl_base()'
Parser.o:(.data.rel.ro._ZTIN5boost6python7objects23caller_py_function_implINS0_6detail6callerIPFNS0_5tupleEPKcENS0_21default_call_policiesENS_3mpl7vector2IS5_S7_EEEEEE [_ZTIN5boost6python7objects23caller_py_function_implINS0_6detail6callerIPFNS0_5tupleEPKcENS0_21default_call_policiesENS_3mpl7vector2IS5_S7_EEEEEE]+0x10): undefined reference to `typeinfo for boost::python::objects::py_function_impl_base'
Parser.o: In function `boost::python::converter::pointer_arg_from_python<char const*>::pointer_arg_from_python(_object*)':
Parser.cpp:(.text._ZN5boost6python9converter23pointer_arg_from_pythonIPKcEC2EP7_object[_ZN5boost6python9converter23pointer_arg_from_pythonIPKcEC5EP7_object]+0x18): undefined reference to `_Py_NoneStruct'
Parser.cpp:(.text._ZN5boost6python9converter23pointer_arg_from_pythonIPKcEC2EP7_object[_ZN5boost6python9converter23pointer_arg_from_pythonIPKcEC5EP7_object]+0x34): undefined reference to `boost::python::converter::get_lvalue_from_python(_object*, boost::python::converter::registration const&)'
Parser.o: In function `boost::python::converter::pointer_arg_from_python<char const*>::operator()() const':
Parser.cpp:(.text._ZNK5boost6python9converter23pointer_arg_from_pythonIPKcEclEv[_ZNK5boost6python9converter23pointer_arg_from_pythonIPKcEclEv]+0x1e): undefined reference to `_Py_NoneStruct'
Parser.o: In function `boost::python::converter::expected_pytype_for_arg<boost::python::tuple>::get_pytype()':
Parser.cpp:(.text._ZN5boost6python9converter23expected_pytype_for_argINS0_5tupleEE10get_pytypeEv[_ZN5boost6python9converter23expected_pytype_for_argINS0_5tupleEE10get_pytypeEv]+0x1b): undefined reference to `boost::python::converter::registry::query(boost::python::type_info)'
Parser.cpp:(.text._ZN5boost6python9converter23expected_pytype_for_argINS0_5tupleEE10get_pytypeEv[_ZN5boost6python9converter23expected_pytype_for_argINS0_5tupleEE10get_pytypeEv]+0x32): undefined reference to `boost::python::converter::registration::expected_from_python_type() const'
Parser.o: In function `boost::python::converter::expected_pytype_for_arg<char const*>::get_pytype()':
Parser.cpp:(.text._ZN5boost6python9converter23expected_pytype_for_argIPKcE10get_pytypeEv[_ZN5boost6python9converter23expected_pytype_for_argIPKcE10get_pytypeEv]+0x1b): undefined reference to `boost::python::converter::registry::query(boost::python::type_info)'
Parser.cpp:(.text._ZN5boost6python9converter23expected_pytype_for_argIPKcE10get_pytypeEv[_ZN5boost6python9converter23expected_pytype_for_argIPKcE10get_pytypeEv]+0x32): undefined reference to `boost::python::converter::registration::expected_from_python_type() const'
Parser.o: In function `boost::python::converter::registration const& boost::python::converter::detail::registry_lookup2<char const volatile>(char const volatile& (*)())':
Parser.cpp:(.text._ZN5boost6python9converter6detail16registry_lookup2IVKcEERKNS1_12registrationEPFRT_vE[_ZN5boost6python9converter6detail16registry_lookup2IVKcEERKNS1_12registrationEPFRT_vE]+0x1f): undefined reference to `boost::python::converter::registry::lookup(boost::python::type_info)'
Parser.o: In function `boost::python::converter::pyobject_type<boost::python::tuple, &PyTuple_Type>::get_pytype()':
Parser.cpp:(.text._ZN5boost6python9converter13pyobject_typeINS0_5tupleEXadL_Z12PyTuple_TypeEEE10get_pytypeEv[_ZN5boost6python9converter13pyobject_typeINS0_5tupleEXadL_Z12PyTuple_TypeEEE10get_pytypeEv]+0x7): undefined reference to `PyTuple_Type'
collect2: error: ld returned 1 exit status
makefile:8: recipe for target 'Parser' failed
make: *** [Parser] Error 1
I see a bunch of boost namespace stuff coming up.
So this leads me to believe that either there is a change in the name mangling between what I've compiled and what is being linked in, or there is a difference with defines which is causing either namespace or other differences.
But I am unsure how to find out the cause, assuming I am correct with my previous assumptions.
EDIT: I had cut the dump short and said that 'most' of it seems to be from boost, but JaMiT called me on it. So theres the full dump.
EDIT 2: I checked my python config and the results are:
user#vm:/usr/local/lib/python3.8/config-3.8-x86_64-linux-gnu$ python python-config.py --cflags
-I/usr/local/include/python3.8 -I/usr/local/include/python3.8 -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall
user#vm:/usr/local/lib/python3.8/config-3.8-x86_64-linux-gnu$ python python-config.py --ldflags
-L/usr/local/lib/python3.8/config-3.8-x86_64-linux-gnu -lcrypt -lpthread -ldl -lutil -lm -lm
EDIT 3:
I used nm on libpython3.8.a from my /usr/local/lib/python3.8/config-3.8-x86_64-linux-gnu and found that PyUnicode_FromString and some others do appear correctly as type 'T' function-with-param.
So they are there.
Thanks to a comment by 'sehe' mentioning ordering of libs, I did some Google searching and found the problem - my linking step in the makefile was:
$(CC) $(COMMONFLAGS) $(LDFLAGS) $(LIBS) -o Parser Parser.o grammar.o words.o
The additional libraries I use should come at the end eg:
$(CC) $(COMMONFLAGS) $(LDFLAGS) -o Parser Parser.o grammar.o words.o $(LIBS)
But after fixing the aforementioned ordering of arguments on the linker invocation, I had additional undefined references crop up from within Python which had not been reported before.
This turned out not to be an issue as building an executable was just step one - making sure the code compiles and I can link.
In the end to get a makefile building a module I can import into Python, I needed to compile all cpp files with -fPIC and then link with -shared -export-dynamic
Python's lib was not needed and so my final libs are -lboost_python38 -lboost_system
After setting my LD_LIBRARY_PATH to point to the boost /stage/lib folder, I was able to import my Parser.so module and it worked correctly.
I am a beginner to organizing C++ projects and I have been trying to start an Open Dynamics Engine project for a week now but I keep getting several errors. First, what I have done:
Installed ode-0.13.1 with automake as directed in the manual.
Created a file test.cpp with the code from the bouncing ball HOWTO.
Wrote a makefile to compile.
But when I run my makefile, I get the following errors:
gcc -Wall -g -DdDOUBLE -o test test.o -L/home/username/ode-0.13.1/ode/src/libode.la -L/home/username/ode-0.13.1/drawstuff/src/libdrawstuff.la -L/usr/X11R6/lib -L/usr/lib -L/usr/local/lib -I. -I/home/username/ode-0.13.1/include/ -I/usr/X11R6/include -I/usr/include -lm -lode -lGL -lGLU
/usr/local/lib/libode.a(collision_trimesh_box.o): In function dCalcVectorLength3':
/home/username/ode-0.13.1/ode/src/../../include/ode/odemath.h:148: undefined reference tosqrt'
/home/username/ode-0.13.1/ode/src/../../include/ode/odemath.h:148: undefined reference to sqrt'
/home/username/ode-0.13.1/ode/src/../../include/ode/odemath.h:148: undefined reference tosqrt'
/usr/local/lib/libode.a(util.o): In function dxStepBody(dxBody*, double)':
/home/username/ode-0.13.1/ode/src/util.cpp:618: undefined reference tosincos'
/home/username/ode-0.13.1/ode/src/util.cpp:630: undefined reference to sincos'
/home/username/ode-0.13.1/ode/src/util.cpp:628: undefined reference tosqrt'
/home/username/ode-0.13.1/ode/src/util.cpp:590: undefined reference to `sqrt'
... (and this keeps going for pages)
/usr/local/lib/libode.a(OPC_AABBTree.o): In function Opcode::AABBTree::Build(Opcode::AABBTreeBuilder*)':
/home/username/ode-0.13.1/OPCODE/OPC_AABBTree.cpp:413: undefined reference tooperator new[](unsigned long)'
/home/username/ode-0.13.1/OPCODE/OPC_AABBTree.cpp:427: undefined reference to operator new[](unsigned long)'
/usr/local/lib/libode.a(OPC_AABBTree.o): In functionOpcode::AABBTreeNode::~AABBTreeNode()':
/home/username/ode-0.13.1/OPCODE/OPC_AABBTree.cpp:83: undefined reference to operator delete[](void*, unsigned long)'
/usr/local/lib/libode.a(OPC_Collider.o): In functionOpcode::Collider::~Collider()':
/home/username/ode-0.13.1/OPCODE/OPC_Collider.cpp:54: undefined reference to operator delete(void*, unsigned long)'
/usr/local/lib/libode.a(OPC_Collider.o):(.data.rel.ro._ZTIN6Opcode8ColliderE[_ZTIN6Opcode8ColliderE]+0x0): undefined reference tovtable for __cxxabiv1::__class_type_info'
/usr/local/lib/libode.a(OPC_Collider.o):(.data.rel.ro._ZTVN6Opcode8ColliderE[_ZTVN6Opcode8ColliderE]+0x20): undefined reference to `__cxa_pure_virtual'
collect2: error: ld returned 1 exit status
makefile:14: recipe for target 'test' failed
make: *** [test] Error 1
These errors seem like the library has not been set up correctly, but I'm pretty sure I've properly installed and my -L's are set to the correct paths.
Note 1: the demos included with the ode library work.
Note 2: I've tried (and failed) to install other versions of ode previously. I did my best with make uninstall and make clean to clean these failed installs, but I think they may be affecting new installs because when I run sudo make install for the first time there is an awful lot of Nothing to do here... messages.
a C++ code built into a shared library for HELib is using NTL and GMP static library. But it gets following error:
/usr/bin/ld: /usr/local/lib/libntl.a(FFT.o): relocation R_X86_64_32 against `.rodata.str1.8' can not be used when making a shared object; recompile with -fPIC
/usr/local/lib/libntl.a: error adding symbols: Bad value
collect2: error: ld returned 1 exit status
It was suggested int the post Click here
to recompile NTL and GMP with "-fPIC " flags.
I'am not able to find how I should do that.
Edit:
I'm able to build the shared library now after :
recompiling GMP and NTL by:
./configure --enable-shared
for gmp and
./configure SHARED=on
After make Install of HELib. I get error when I run the example codes.
The link to the Makefile : click to see makefile
Error:
g++ -g -O2 -std=c++11 -pthread -DFHE_THREADS -DFHE_BOOT_THREADS -DFHE_DCRT_THREADS -o Test_General_x Test_General.cpp -L/usr/local/lib -lntl -lgmp -lm -lfhe
/usr/local/lib/libfhe.so: undefined reference to write_raw_int(std::ostream&, long, long)'
/usr/local/lib/libfhe.so: undefined reference toread_raw_ZZ(std::istream&, NTL::ZZ&)'
/usr/local/lib/libfhe.so: undefined reference to void write_raw_vector<long>(std::ostream&, std::vector<long, std::allocator<long> > const&)'
/usr/local/lib/libfhe.so: undefined reference towriteEyeCatcher(std::ostream&, char const*)'
/usr/local/lib/libfhe.so: undefined reference to write_raw_xdouble(std::ostream&, NTL::xdouble)'
/usr/local/lib/libfhe.so: undefined reference toread_ntl_vec_long(std::istream&, NTL::Vec&)'
/usr/local/lib/libfhe.so: undefined reference to void read_raw_vector<long>(std::istream&, std::vector<long, std::allocator<long> >&)'
/usr/local/lib/libfhe.so: undefined reference toreadEyeCatcher(std::istream&, char const*)'
/usr/local/lib/libfhe.so: undefined reference to read_raw_int(std::istream&, long)'
/usr/local/lib/libfhe.so: undefined reference toread_raw_xdouble(std::istream&)'
/usr/local/lib/libfhe.so: undefined reference to write_raw_ZZ(std::ostream&, NTL::ZZ const&)'
/usr/local/lib/libfhe.so: undefined reference towrite_ntl_vec_long(std::ostream&, NTL::Vec const&, long)'
collect2: error: ld returned 1 exit status
Makefile:179: recipe for target 'Test_General_x' failed
make: *** [Test_General_x] Error 1
For NTL v11.5.1 atleast, doing ./configure --help | grep -i pic (as suggested in one of the comments for GMP) did not help at all - it found no matches. However, making a one line change in the file ntl-11.5.1/src/DoConfig (on line 17) from:
'CXXFLAGS' => '-g -O2'
to:
'CXXFLAGS' => '-g -O2 -fPIC',
solved the problem for me.
Marc Glisse provided the answer for the first two parts of the question.For the third part "Undefined Reference error" the answer is I'd not compiled and linked a x.cpp containing the functions that caused the undefined reference into my shared library. hence check : nm -CD /usr/local/lib/libfhe.so to see if these functions are listed with a linking address or not. If not then check which code provides this functionality. Link that code to the shared library.