passing a seed through different boost random number generator - c++

Question

I am passing a streamstring from one random generator to another to keep track of the current state of an engine (boost random library). It allows me stop at any point and save the current state to reproduce a series later on in the code or continue it.
It works fine until I use different random generators while passing the same stringstream (as reproduce bellow). I cannot use different streams for the two, as in the real example a class will call to different distributions in a random order...
#ifndef RANDOM_HPP
#define RANDOM_HPP
namespace RandomG{
using namespace std;
using namespace boost::random;
int getSeed()
{
ifstream rand("/dev/urandom");
char tmp[sizeof(int)];
rand.read(tmp,sizeof(int));
rand.close();
int* number = reinterpret_cast<int*>(tmp);
return (*number);
}
void Get_Rstream(stringstream &s)
{
mt19937 randgen(getSeed());
s.clear();
s << randgen;
}
template<class distribution>
class Random
{
public:
Random(distribution nd)
{
mt19937 randgen(getSeed());
rng=new variate_generator<mt19937,distribution >(randgen, nd);
}
virtual ~Random()
{
delete rng;
}
void reset(void)
{
(*rng).distribution().reset();
}
double operator()(stringstream &s)
{
double x;
s >> (*rng).engine();
x=(*rng)();
return x;
}
variate_generator<mt19937,distribution > *rng;
};
}
#endif
So now if I instantiate two instances of these classes (below its two uniform but it could be a uniform and a Gaussian or anything else and could be called in a random order).
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <boost/random/mersenne_twister.hpp>
#include <boost/random/normal_distribution.hpp>
#include <boost/random/variate_generator.hpp>
#include "Random.hpp"
using namespace boost::random;
using namespace std;
int main()
{
int M=20;
stringstream ss;
RandomG::Get_Rstream(ss);
string ss2=ss.str();
stringstream ss3;
ss3.clear();
ss3.str(ss.str());
boost::random::uniform_01<> N;
RandomG::Random<boost::random::uniform_01<> > *unif_rand1= new RandomG::Random<boost::random::uniform_01<> >(N);
boost::random::uniform_01<> U;
RandomG::Random<boost::random::uniform_01<> > *unif_rand2=new RandomG::Random<boost::random::uniform_01<> >(U);
(*unif_rand1).reset();
(*unif_rand2).reset();
for(int i=0;i<M;i++)
{
cout << (*unif_rand1)(ss) << " ";
}
for(int i=0;i<M;i++)
{
cout << (*unif_rand2)(ss) << " ";
}
cout <<"\\\\\\\\\\\\\\\\\\\\"<<"\n";
(*unif_rand1).reset();
(*unif_rand2).reset();
for(int i=0;i<M;i++)
{
cout << (*unif_rand1)(ss3) << " ";
}
for(int i=0;i<M;i++)
{
cout << (*unif_rand2)(ss3) << " ";
}
return 0;
}
This should give me two series of the same random numbers, but instead gives me the same random numbers for unif_rand1 but not for unif_rand2.
From what I understood feeding the same state to two different random number generator should give the same result or is there some way to reset them between draws ?
results:
0.525384 0.038626 0.563798 0.705042 0.725001 0.311586 0.843047 0.606338 0.163695 0.437574 \\\\\\\\\\
0.525384 0.038626 0.563798 0.705042 0.725001 0.0566288 0.93966 0.417343 0.686245 0.84118
Thanks for any responses or advises
(the code should be reproducible under linux).