function template
<memory>

std::get_deleter

template <class D, class T>
  D* get_deleter (const shared_ptr<T>& sp) noexcept;
Get deleter from shared_ptr
Returns a pointer to the deleter owned by sp.

If sp has no deleter, and thus would use ::delete to delete its managed object, the function returns a null pointer.

The returned value is valid at least as long as there exists a shared_ptr instance that owns that deleter.

Notice that the first template parameter is the return type, and thus cannot be automatically deduced by the compiler.

Parameters

sp
A shared_ptr object.

Return Value

A pointer to the owned deleter, if any. Or a null pointer otherwise.

Example

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// get_deleter example
#include <iostream>
#include <memory>

struct D {    // a verbose array deleter:
  void operator()(int* p) {
    std::cout << "[deleter called]\n";
    delete[] p;
  }
};

int main () {
  std::shared_ptr<int> foo (new int[10],D());

  int * bar = new int[20];

  // use foo's deleter to delete bar (which is unmanaged):
  (*std::get_deleter<D>(foo))(bar);

  return 0;
  // foo's deleter called automatically
}


Output:
[deleter called]
[deleter called]

See also