When using legacy C++ driver, cannot connect to replica set servers. Although I can connect to every member separately with no problem. When multiple servers are specified in connection string, empty pointer is returned from cs.connect().

Code snippet:
#include <mongo/client/dbclient.h>
#include <mongo/client/options.h>
#include <mongo/client/init.h>
#include <mongo/bson/bson.h>
#include <iostream>
#include <memory>
#include <iostream>

using namespace mongo;
using namespace std;

int main() {
string rsName = "myProductionSet";
string err;
bool master;

client::Options opt;
client::initialize(opt);
ConnectionString cs = ConnectionString::parse("mongodb://[host1]:27017,[host2]:27117/?replicaSet=myProductionSet",err);

DBClientReplicaSet* client = static_cast<DBClientReplicaSet*>(cs.connect(err));
if(!client)

{ cout << "Empty pointer" << endl; }

if(client->isMaster(master))
std::cout << "OK" << std::endl;
else
std::cout << "ERR" << std::endl;

return 0;
}