#include <iostream>
#include <memory>

struct EmptyDeleter {
    void operator()(int* p) noexcept { delete p; }
};

// 有状态删除器：带数据成员，没法 EBO
struct StatefulDeleter {
    int extra;
    void operator()(int* p) noexcept { delete p; }
};

int main() {
    std::cout << "sizeof(int*):                             " << sizeof(int*) << "\n";
    std::cout << "sizeof(unique_ptr<int>):                  " << sizeof(std::unique_ptr<int>)
              << "\n";
    std::cout << "sizeof(unique_ptr<int, EmptyDeleter>):    "
              << sizeof(std::unique_ptr<int, EmptyDeleter>) << "\n";
    std::cout << "sizeof(unique_ptr<int, void(*)(int*)>):   "
              << sizeof(std::unique_ptr<int, void (*)(int*)>) << "\n";
    std::cout << "sizeof(unique_ptr<int, StatefulDeleter>): "
              << sizeof(std::unique_ptr<int, StatefulDeleter>) << "\n";
}