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

Answer 1

The compiler will optimize it.

Except in some situations, such as:

std::string f(bool cond = false)
{
  std::string first("first");
  std::string second("second");
  // the function may return one of two named objects
  // depending on its argument. RVO might not be applied
  if(cond)
    return first;
  else
    return second;
}

Of course there can be some old compilers, which can call copy constructor. But you shouldn't worry about it with modern compilers.