[Boost-users] [1.33] [signals] auto_ptr and boost::signals

26 Aug 2007

      Dears

I have question.

Why there are problems to connect function that returns auto_ptr to the 
signal? Below there is a code which won't compile i line where is comment.

Regards.

#include <iostream>
#include <boost/signals.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/bind.hpp>
#include <memory>
#include <vector>
#include <iterator>
#include <algorithm>

class some_class {
public:
  ::std::vector <int> func1() {
    using ::std::vector;
    typedef vector <int> Res;

    Res res (2);
    res.at(0) = 13;
    res.at(1) = 14;
    return res;
  }

  ::boost::shared_ptr < ::std::vector <int> > func2() {
    using ::std::vector;
    using ::boost::shared_ptr;
    typedef shared_ptr < vector <int> > Res;

    Res res (new vector<int> (2));
    res->at(0) = 23;
   res->at(1) = 24;
    return res;
  }

  ::std::auto_ptr < ::std::vector <int> > func3() {
    using ::std::vector;
    using ::std::auto_ptr;
    typedef auto_ptr < vector <int> > Res;

    Res res (new vector<int> (2));
    res->at(0) = 33;
    res->at(1) = 34;
    return res;
  }
};

int main()
{
  using ::boost::signal;
  using ::std::vector;
  using ::std::auto_ptr;
  using ::boost::shared_ptr;
  using ::boost::bind;

  some_class sc;

  signal < vector <int> (void) > sig1;
  signal < shared_ptr < vector <int> > (void) > sig2;
  signal < auto_ptr < vector <int> > (void) > sig3;

  sig1.connect (bind (&some_class::func1,&sc));
  vector <int> ret1 (sig1());

  ::std::copy (ret1.begin(), ret1.end(), 
    ::std::ostream_iterator<int> (::std::cout, "\n"));

  sig2.connect (bind (&some_class::func2,&sc));
  vector <int> ret2 (*sig2());

  ::std::copy (ret2.begin(), ret2.end(), 
    ::std::ostream_iterator<int> (::std::cout, "\n"));

  sig3.connect (bind (&some_class::func3,&sc));
  //sig3(); // <- ERROR

}

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