Memory leak of solutions at Engine in a multi-threading context #156

#include <gecode/int.hh>
#include <gecode/search.hh>

using namespace Gecode;

class SendMoreMoney : public Space {
protected:
  IntVarArray l;
public:
  SendMoreMoney(void) : l(*this, 8, 0, 9) {
    IntVar s(l[0]), e(l[1]), n(l[2]), d(l[3]),
           m(l[4]), o(l[5]), r(l[6]), y(l[7]);
    // no leading zeros
//    rel(*this, s, IRT_NQ, 0);
//    rel(*this, m, IRT_NQ, 0);
    // all letters distinct
//    distinct(*this, l);
    // linear equation
    IntArgs c(4+4+5); IntVarArgs x(4+4+5);
    c[0]=1000; c[1]=100; c[2]=10; c[3]=1;
    x[0]=s;    x[1]=e;   x[2]=n;  x[3]=d;
    c[4]=1000; c[5]=100; c[6]=10; c[7]=1;
    x[4]=m;    x[5]=o;   x[6]=r;  x[7]=e;
    c[8]=-10000; c[9]=-1000; c[10]=-100; c[11]=-10; c[12]=-1;
    x[8]=m;      x[9]=o;     x[10]=n;    x[11]=e;   x[12]=y;
    linear(*this, c, x, IRT_EQ, 0);
    // post branching
    branch(*this, l, INT_VAR_SIZE_MAX(), INT_VAL_MAX());
  }
  // search support
  SendMoreMoney(SendMoreMoney& s) : Space(s) {
    l.update(*this, s.l);
  }
  virtual Space* copy(void) {
    //std::cout << "Clone occurred" << std::endl;
    return new SendMoreMoney(*this);
  }
  // print solution
  void print(void) const {
    std::cout << l << std::endl;
  }

  ~SendMoreMoney() {
    //std::cout << "Destructor Ok" << std::endl;
  }
};

// main function
int main(int argc, char* argv[]) {

  Gecode::Search::Options opt;
  opt.threads = 8;
  opt.c_d     = 1;
      
  // create model and search engine
  SendMoreMoney* m = new SendMoreMoney;
  DFS<SendMoreMoney> e(m, opt);
  delete m;
  // search and print all solutions
  if (SendMoreMoney* s = e.next()) {
    s->print(); delete s;
  }
  return 0;
}