Dynamic library using static library in c++ name mangling error

Question

I am trying to create a dynamic(.so) wrapper library along mongoDB c++ driver. There is no problem with the compilation but when I test it in a C++ sample program i get the error

undefined symbol: _ZN5mongo18DBClientConnection15_numConne

which i assume has something to do with name mangling issues.

I compiled the library as

g++ -fPIC -shared mongoquery.cpp -I/pathto/mongodriver -lmongoclient -lboost_thread-mt -lboost_filesystem -lboost_program_options -o libmongoquery.so

Here's the program I am using for testing:

#include <iostream>
#include <dlfcn.h>
#include "mongoquery.hpp"
using namespace std;

int main()
{
    void *lib_handle;
    int (*fn)(int *,string);
    lib_handle=dlopen("./libmongoquery.so",RTLD_NOW);
    if(!lib_handle)
    {
        cerr<<"Error"<<dlerror();
        return 1;
    }
    fn=(int (*)(int *,string))dlsym(lib_handle,"count_query");
    string q="{}";
    int n;
    (*fn)(&n,q);
    cout<<n;
    dlclose(lib_handle);
return 0;
}

the header mongoquery.hpp contains

#include <iostream>
#include <client/dbclient.h>
#define HOST "localhost"
#define COLLECTION "test.rules"
using namespace mongo;
using namespace std;
class mongoquery
{
    private:
        string q;
        mongo::DBClientConnection c;


    public:
        mongoquery(string);
        int result_count();
};
int count_query(int *,string);

Thanks

Answer 1

The answer can be followed from this question

Dynamic library uses statics libraries, undefined symbols appears

Added for achival purpose