Why was auto_ptr removed?

Since the assignment-semantics was most-disliked feature, they wanted that feature to go away, but since there is code written that uses that semantics, (which standards-committee can not change), they had to let go of auto_ptr, instead of modifying it.

Why is auto_ptr deprecated?

Why is auto_ptr deprecated? It takes ownership of the pointer in a way that no two pointers should contain the same object. Assignment transfers ownership and resets the rvalue auto pointer to a null pointer. Thus, they can’t be used within STL containers due to the aforementioned inability to be copied.

Why is auto_ptr bad?

This is because auto_ptr has semantics of strict ownership and is thus solely responsible for an object during the object’s life cycle. Since objects within an STL container must be copy-constructible and assignable, a compile time error is provided if an auto_ptr is used within a container.

When was auto_ptr removed?

auto_ptr was fully removed in C++17. For shared ownership, the shared_ptr template class can be used. shared_ptr was defined in C++11 and is also available in the Boost library for use with previous C++ versions.

What is std :: Auto_ptr?

std::auto_ptr auto_ptr is a smart pointer that manages an object obtained via new expression and deletes that object when auto_ptr itself is destroyed.

How do I use sharedPTR?

You can pass a shared_ptr to another function in the following ways:

1. Pass the shared_ptr by value.
2. Pass the shared_ptr by reference or const reference.
3. Pass the underlying pointer or a reference to the underlying object.

How are shared pointers implemented?

It is a reference counting ownership model i.e. it maintains the reference count of its contained pointer in cooperation with all copies of the std::shared_ptr. So, the counter is incremented each time a new pointer points to the resource and decremented when destructor of the object is called.

What happened when a pointer is deleted twice?

I know that a “deleting the same memory twice” error can happen when two pointers address the same dynamically allocated object. If delete is applied to one of the pointers, then the object’s memory is returned to the free store. If we subsequently delete the second pointer, then the free store may be corrupted.

What is Make_shared in C++?

std::make_shared Allocates and constructs an object of type T passing args to its constructor, and returns an object of type shared_ptr that owns and stores a pointer to it (with a use count of 1). This function uses ::new to allocate storage for the object.

Why use make shared?

Using make_shared makes a difference because it could prolong the life-time of the memory allocated for the managed object. When the shared_ptr count hits 0, the destructor for the managed object gets called regardless of make_shared , but freeing its memory can only be done if make_shared was not used.

Can shared pointer be null?

A shared_ptr that points to no object is called a null shared_ptr and shall not be dereferenced.