What happens when using make_shared

Question

I\'m interested if these two lines of code are the same:

shared_ptr sp(new int(1)); // double allocation?
shared_ptr sp(make_shared<         


        

Answer 1

There is also a potential subtle bug: in sp(new int) you fist allocate an int (whose pointer is given to sp), than sp itself has to allocate a control block (will contain the counters and the deleter).

Now, if doing this last allocation sp fails (low memory) you are left with a heap allocated int whose pointer is not held by anyone, and thus impossible to delete. (memory leak).