Creating and returning a big object from a function [duplicate]

Answer 1

I don't know why nobody pointed out the obvious solution yet. Just pass the output object by reference:

void f(Object& result) {
  result.do_something();
  result.fill_with_values(/* */);
};

This way:

• you avoid the copy for sure.

• you avoid using the heap.

• you avoid leaving the calling code with the responsibility of freeing the dynamically-allocated object (although shared_ptr or unique_ptr would do that too).

Another alternative is to make the function a member of Object, but that might not be appropriate, depending on what f()'s contract is.