std::get_deleter on std::shared_ptr initialized with std::bind - c++

Question

Let's say I have this code:
class BaseObject
{
public:
virtual void OnDestroy() {}
};
template <typename T>
struct myArrayDeleter
{
void operator()(T *p, std::size_t count)
{
for(std::size_t i = 0; i < count; i++)
{
static_cast<BaseObject*>((void*)(int(p) + sizeof(T) * i))->OnDestroy();
}
delete [] p;
}
};
And let's assume that it works as intended (it's a simplified version, written now without the check but basically you know what this code should do).
With this part I don't have a problem. However, check this out:
class AActor
: public BaseObject
{
public:
virtual void OnDestroy() override
{
// some code here
}
};
template <typename T>
class SimplifiedHolder
{
protected:
std::shared_ptr<T> m_shared;
std::size_t m_size;
public:
// Some not important code here
// WE ASSUME HERE THAT IT ALWAYS HOLDS ARRAY
// sizeOfArray always > 1
template <typename U>
SimplifiedHolder(U *ptr, std::size_t sizeOfArray)
: m_size(sizeOfArray)
{
m_shared = std::shared_ptr<T>(ptr,
std::bind(&myArrayDeleter<U>(), std::placeholders::_1, m_size));
}
// And now as we initialize our shared_ptr with template
// we can check if it is exactly of type "U"
template <typename U>
bool IsExactlyOfType()
{
if(!m_shared)
return false;
return ((void*)std::get_deleter<myArrayDeleter<U>>(m_shared)) != nullptr;
}
};
However, the method IsExactlyOfType isn't working. That's because I initialized shared_ptr with std::bind. std::get_deleter always returns nullptr because the wrong type is specified in the template. I don't know what type to pass. I tried also with non-array code in which myDeleter is a functor with only one argument and it works perfectly with code like this:
template <typename U>
bool IsExactlyOfType()
{
if(!m_shared)
return false;
return ((void*)std::get_deleter<myDeleter<U>>(m_shared) != nullptr;
}
I know I could go with typeid(U) == typeid(*m_shared.get()) but this is not what I want. I have much more complicated code and in that case only this method is good.
Can a more experienced programmer tell me what type to specify to std::get_deleter?

Answer 1

It turned out that compiler wasn't translating decltype correctly. I tried to get deleter immediately after initializing shared_ptr and it worked. However the same decltype in function was generating slightly other type. I checked it in debugger and it generated this results:
In constructor:
std::_Binder<std::_Unforced,grim::impl::TObjectArrayDeleter<APlayer>,std::_Ph<1> const &,unsigned int &> &
In function:
std::_Binder<std::_Unforced,grim::impl::TObjectArrayDeleter<APlayer>,std::_Ph<1> const &,unsigned int const &> *
Take a look at the end - it appended additional const. I needed to change it manually, so now my code looks like this:
using D = std::_Binder<std::_Unforced,grim::impl::TObjectArrayDeleter<U>,
std::_Ph<1> const &,unsigned int &>;
return ((void*)std::get_deleter<D>(m_shared)) != nullptr;