[Boost-users] Error populating pointer container with stack based objects

From: Allen Cronce (acronce_at_[hidden])
Date: 2005-09-23 17:04:31

Hi all,

I'm seeing a compile error when trying to populate a pointer container
with stack based objects. What's supposed to happen is the stack-based
object should be cloned and the resulting new object inserted in the
container. But I'm only able to insert new objects, not stack-based
ones. The object I'm trying to copy is Cloneable in
accordance with the Pointer Container Library docs (I think). I'm using
the Boost CVS build from
September 15th under CodeWarrior 9.5/MSL on
Mac OS X.

Here's a code sample that demonstrates the problem:

--snip--

// Forward reference for required clone function
class    StringWrapper;
StringWrapper* new_clone( const StringWrapper&
a );

class    StringWrapper : public boost::totally_ordered<StringWrapper>
    {
    public:
        StringWrapper() 
            {
            }

        StringWrapper(LPCTSTR in_psz):
            m_str(in_psz)
            {
            }                      
          
        ~StringWrapper() 
            {
            }
        
        StringWrapper(const StringWrapper&
in_RHS ):
            m_str(in_RHS.m_str)
            {
            }
                        
        StringWrapper&        operator=( const
StringWrapper& in_RHS    )
            {
            m_str    = in_RHS.m_str;
            return *this;
            }
                                
        StringWrapper*        clone() const
            {
            return do_clone();
            }

        bool operator < (const StringWrapper&
in_RHS) const
            {
            return (m_str < in_RHS.m_str);
            }
            
        bool operator == (const StringWrapper&
in_RHS) const
            {
            return (m_str == in_RHS.m_str);
            }

        std::string    m_str;
    
    private:
        virtual StringWrapper* do_clone() const
            {
            return new StringWrapper(*this);
            }
    };

// Function needed for pointer container library object cloning
StringWrapper* new_clone( const StringWrapper&
a )
    {
    return a.clone();
    }

// test code
typedef    boost::ptr_vector<StringWrapper>    StringWrapperVector;
typedef    StringWrapperVector::iterator       StringWrapperVectorIterator;
StringWrapperVector        swv1;

// The following generates a compile error:
StringWrapper    tempString("Copy me!");
swv1.push_back(tempString);        // should call the StringWrapper
clone method

// The following works correctly:
swv1.push_back(new StringWrapper("I'm dynamic 1!"));
swv1.push_back(new StringWrapper("I'm dynamic 2!"));

--snip--

The compiler error is as follows:

Error   : function call
'[boost::ptr_vector<StringWrapper,
boost::heap_clone_allocator, std::allocator<void
*>>].push_back({lval} StringWrapper)' does not match
'boost::ptr_sequence_adapter<StringWrapper, std::vector<void *,
std::allocator<void *>>,
boost::heap_clone_allocator>::push_back(StringWrapper *)'
(non-static)
MiniTest.c line 33622     swv1.push_back(tempString);  // should call
the StringWrapper clone method 

Any suggestions would be appreciated.

Best regards,
--
Allen Cronce