Assigning local std::vector to reference in C++

Question

I am not sure if my approach is correct. Since I am passing vector v by reference to Function , after it's execution vector's content will change.

What if I can't work directly on vector v and decide to use temporary vector temp . Is assigning to v my temporary through v = temp correct? Won't reference v point at some memory which will be swept after execution of Function ?

void Function(std::vector<bool> &v) {
  std::vector<bool> temp(v.size(), false);

  // some operations on vector temp
  // ...

  v = temp;
}

Answer 1

Won't reference v point at some memory which will be swept after execution of Function ?

No. For v = temp; , v is copy assigned from temp . Then v will contain the same content with temp , but it has nothing to do with temp ; temp ia a local variable which will be destroyed later, but the argument passed in won't be affected.

BTW: Since temp is a local variable which will be destroyed when get out of the function, copying from it will be waste. You could move from it:

v = std::move(temp);

Answer 2

Yes, assigning v = temp is safe. For further information look at eg: https://isocpp.org/wiki/faq/references#overview-refs