boost::ptr_vector and find_if

Question

I have a class:

//header file
class CMDatabase
{
    class Try;
    typedef boost::shared_ptr TryPtr;
    typedef boost::ptr_vector TryVect         


        

Answer 1

The issue is that your equal method is not const qualified.

class Try
{
public:
  virtual ~Try();
  virtual bool equal(CMDatabase::TryPtr const& mySd) const = 0;
};

bool TryImpl::equal(CMDatabase::TryPtr const& mySd) const { return true; }

Note:

• the const added to the method, otherwise it cannot be used on const objects
• the const added on the pointer: copying shared_ptr does cost, because it necessitates incremented a shared counter, and decrementing it afterward.

EDIT:

Reminder for the unwary: the Pointer Container library has been designed so that the interface would be as easy to use a possible, and one of the goody is that you don't have to double dereference. This compiles:

 boost::ptr_vector vec;
 vec.push_back(new int(3));

 int& i = *vec.begin();

Thus, your functor must take a reference, not a pointer :)