Creates a QSharedPointer that is null. This is equivalent to the QSharedPointer default constructor.
The deleter parameter d specifies the custom deleter for this 
object. The custom deleter is called, instead of the operator delete(), 
when the strong reference count drops to 0.

#include <iostream>
#include <memory>#include <QtCore/QSharedPointer>int main() {
  std::shared_ptr<int>(nullptr, [](int *i) {
    std::cout << "deleter std::shared_ptr" << std::endl;
  });
  QSharedPointer<int>(nullptr, [](int *i) {
    std::cout << "deleter QSharedPointer" << std::endl;
  });
}

deleter std::shared_ptr