//This example demostrate the gist of why higher order function can be more save
//1. Higher order functions are the functions that take a function as param or return a function
//2. Higher order functions take care of the safty by automatically doing some safe check before
//   invoking some user-defined function, thus avoid undefined behaviors.
//3. Similar functionality can be applied to automatically check if pointer is valid before using
//   a unique pointer.

#include <mutex>

template <typename T>
class Lock
{
    T* m_data;
    std::mutex m_mutex;

public:
    template <typename F>
    decltype(auto) access(F&& func)
    {
        std::lock_guard lock_guard(m_mutex);
      // make sure the mutex is locked before manipulating the resource
        return std::forward<decltype(func)>(func)(m_data);
    }
};



int main()
{
    Lock<int> resource_manager;
    resource_manager.access([](int* data){data = new int;});
}