make_shared x new

Using new, counters are allocated separatelly, them the object and memory is dealocated with de last shared

#include <memory>

using namespace std;

struct X
{
	int b[1000];
};

int main()
{
	{
		weak_ptr<X> wp; //lives longer than shared_ptr
		{
			shared_ptr<X> sp(new X());
			wp = sp;
		}
	}	
}

makeThe object destructor is called with the last shared

From the standard:

Remarks: Implementations are encouraged, but not required, to perform no more than one memory
allocation.  Note: this provides efficiency equivalent to an intrusive smart pointer. end note 

#include <memory>

using namespace std;

struct X
{
	int b[1000];
};

int main()
{
	{
		weak_ptr<X> wp; //lives longer than shared_ptr
		{
			shared_ptr<X> sp = make_shared<X>();
			wp = sp;
		}
	}	
}