is it better to use shared_ptr.reset or operator =?

Question

I\'m trying to wrap my head around the new idioms for C++11.

It seems that with shared_ptr at least, there is a substantive difference between using new T()

Answer 1

Correct, reset(new T...) suffers all the issues of shared_ptr(new T...); it will result in double allocation and also is non-exception-safe (there's not much chance of a leak, unless bad_alloc happens within reset).

reset is documented as equivalent to shared_ptr(ptr).swap(*this), so you could also write:

make_shared(args...).swap(mysharedptr);

Assignment from make_shared is almost equivalent, the only difference being the relative order of the deletion of the old T and the destruction of the temporary shared_ptr, which is not observable.