No, the code causes a memory leak. release is used to release ownership of the managed object without deleting it:
auto v = make_unique<int>(12); // manages the object
int * raw = v.release(); // pointer to no-longer-managed object
delete raw; // needs manual deletion
Don’t do this unless you have a good reason to juggle raw memory without a safety net.
To delete the object, use reset.
auto v = make_unique<int>(12); // manages the object
v.reset(); // delete the object, leaving v empty