CODEWITHSUNDEEP
c++unique-ptr
Paco G
Paco G

Reputation: 421

C++ unique_ptr acts like it's copying the value

In this code:

using namespace std;

int main() {
    int x = 11;
    int* rawPointer = &x;
    unique_ptr<int> integerPointer = make_unique<int>(x);
    cout << *rawPointer << std::endl;
    x++;
    cout << *rawPointer << std::endl;

    return 0;
}

when we ask for the value of rawPointer, the output is :

11
12

which is correct. But when we ask for the value of integerPointer, which happens to be a unique pointer, we get the output :

11
11

I would have thought that it would behave just like rawPointer. Why is that? Is that really the way unique pointers work?

Thanks

Upvotes: 0

Views: 75

Answers (1)

Marco Pantaleoni
Marco Pantaleoni

Reputation: 2539

From the std::unique_ptr reference docs:

Constructs an object of type T and wraps it in a std::unique_ptr.

So you're constructing a new copy, managed by the unique_ptr by passing x, and not managing x by address.

Upvotes: 1

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