Deque Pointer Memory Leak

Question

I have a struct in which i have used std::deque

class VariantWrapper;
typedef _STL_NAMESPACE_::deque<VariantWrapper> VariantQueue;

struct AttributeValueWrapper
{
AttributeValueWrapper() : bAttributeIsArray(false)
{
    pVariantQueue = new VariantQueue;
    if(!pVariantQueue)
        throw std::bad_alloc();
}
AttributeValueWrapper(const AttributeValueWrapper& a)
{
    pVariantQueue = a.TakeOwner();
    bAttributeIsArray = a.bAttributeIsArray;
}
AttributeValueWrapper& operator=(AttributeValueWrapper& r)
{
    throw std::bad_exception("equal operator not supported in AttributeValueWrapper");
}
VariantQueue* TakeOwner() const
{
    VariantQueue *p = pVariantQueue;
    pVariantQueue = NULL;
    return p;
}
~AttributeValueWrapper()
{
    if (pVariantQueue)
    {
        delete pVariantQueue;
    }

}

bool bAttributeIsArray;
mutable VariantQueue *pVariantQueue;};

Main Method:

int main()
{
 AttributeValueWrapper attrib;
}

I am running this code under Dr Memory (This is just a piece of code , project is quite big) and Dr Memory showing a memory leak at pVariantQueue = new VariantQueue inside the default constructor as:

Error #46: LEAK 8 direct bytes + 324 indirect bytes replace_operator_new d:\\drmemory_package\\common\\alloc_replace.c(2899): std::_Allocate<> ??:0 std::allocator<>::allocate ??:0 std::_Wrap_alloc<>::allocate ??:0 std::_Deque_alloc<>::_Alloc_proxy ??:0 std::_Deque_alloc<>::_Deque_alloc<> ??:0 std::deque<>::deque<> ??:0 AttributeValueWrapper::AttributeValueWrapper

Please share you thoughts on this issue.

I have also tried using std::unique_ptr , but still getting the same memory leak at same line no(same point):

struct AttributeValueWrapper
{
AttributeValueWrapper() : bAttributeIsArray(false)
{
    pVariantQueue = std::make_unique<VariantQueue>(new VariantQueue);
    if(!pVariantQueue)
        throw std::bad_alloc();
}
AttributeValueWrapper(const AttributeValueWrapper& a)
{
    pVariantQueue = a.TakeOwner();
    bAttributeIsArray = a.bAttributeIsArray;
}
AttributeValueWrapper& operator=(AttributeValueWrapper& r)
{
    throw std::bad_exception("equal operator not supported in AttributeValueWrapper");
}
std::unique_ptr<VariantQueue> TakeOwner() const
{
    std::unique_ptr<VariantQueue> p = std::move(pVariantQueue);
    pVariantQueue = NULL;
    return p;
}

~AttributeValueWrapper()
{

}

bool bAttributeIsArray;
mutable std::unique_ptr<VariantQueue> pVariantQueue;

};

Now getting memory leak at

pVariantQueue = std::make_unique<VariantQueue>(new VariantQueue);

Vinay

Answer 1

Your memory leak can most likely be found in the destructor. What happens to the objects in the queue when the queue goes away?