Which smart pointer should be used when you want a reference counted pointer?
What Pointer Should I Use, and When? As a general rule of thumb, I recommend using std::unique_ptr as your default smart pointer. If you find that you need to share data or utilize reference counting, you should use a std::shared_ptr .
Should smart pointers be passed by reference?
It’s ok to pass a smart pointer by reference, except if it’s to a constructor. In a constructor, it’s possible to store a reference to the original object, which violates the contract of the smart pointers. You would likely get memory corruption if you did that.
How do I pass a shared pointer by reference?
You can pass a shared_ptr to another function in the following ways:
- Pass the shared_ptr by value.
- Pass the shared_ptr by reference or const reference.
- Pass the underlying pointer or a reference to the underlying object.
What smart pointers are and why one should use them?
Smart pointers try to prevent memory leaks by making the resource deallocation automatic: when the pointer to an object (or the last in a series of pointers) is destroyed, for example because it goes out of scope, the pointed object is destroyed too.
What happens to reference count when external pointer is freed?
Even if external pointers are freed, the internal pointers will still count, and the reference count will not reach 0. That is, at least, with the most naïve implementation. The easiest solution to the cycle problem is mixing shared_ptr (reference counted pointers) with weak pointers that do not share the ownership of the object.
How does reference counting smart pointers reference counting work?
The class that implements RC basically keeps count of number of references (from other objects of the class, including its own) to the memory address that it is managing. The memory is freed only when the reference count to the memory address is zero.
What happens to reference count when weak pointer is used?
When you use weak pointers, the reference count is doubled: there is a shared pointer reference count and a weak pointer reference count. The resource is released whenever the shared pointer count reaches 0, but the reference_count information is left alive until the last weak pointer is released.
How are smart pointers designed to free memory?
Smart Pointers are designed to free the memory they’re managing when they die. In the case of SharedPtr, it ensures that there are no other references to the memory being managed before freeing the memory. All of these happen in the object’s Destructor.