To be tested...

regex.cpp

#include<string>
#include<set>
#include<iostream>
#include<sstream>
#include<regex>

using namespace std;

set<string> get_strings(istream& is, regex pat);

int main()
{
  std::string str;

  str += "http://loic-joly.developpez.com/articles/5Mythes/#L6\n";
  str += "http://www.plandeparis.info/metro-paris/metro-paris.gif\n";
  str += "https://mail.google.com/mail/u/0/#inbox\n";

  stringstream ss(str);
  regex pat("http.*m");
  set<string> cont = get_strings(ss, pat);

  for(std::set<string>::iterator it = cont.begin(); it != cont.end(); ++it)
  {
    std::cout << "str = " << *it << std::endl;
  }

  return 0;
}

set<string> get_strings(istream& is, regex pat)
{
  set<string> res;
  smatch m;

  for(string s; getline(is, s); )  // lit une ligne

  if (regex_search(s, m, pat))
    res.insert(m[0]);              // sauve le résultat dans set

  return res;
}