Is there a recommended way to test if a smart pointer is null?

Question

I'm trying to check if a std::shared_ptr is null. Is there a difference between doing

std::shared_ptr<int> p;
if (!p) { // method 1 }
if (p == nullptr) { // method 2 }

Answer 1

Is there a difference between doing

 std::shared_ptr<int> p;
 if (!p) { // method 1 }
 if (p == nullptr) { // method 2 }

No, there's no difference. Either of that operations has a properly defined overload.

Another equivalent would be

 if(p.get() == nullptr)

Answer 2

shared_ptr provides a specific operator for bool conversion std::shared_ptr::operator bool.

Test if not set:

if (!p)

Test if set:

if (p)

You can be very explicit about your intent with:

if (static_cast<bool>(p))