What? That's one of the primary motivations! "I have created an object and will pass its unique ownership to you." -> std::unique_ptr "This routine needs a fu

What? That's one of the primary motivations! "I have created an object and will pass its unique ownership to you." -> std::unique_ptr "This routine needs a function that takes two ints and returns a float (without putting all my code into headers)." -> std::function<float(int, int)>. Can you elaborate in what circumstance you should not pass std::types across API boundaries?