0

I understand how to use the C++11 delete keyword to create classes that can't be copied or moved, but in Bjarne Stroustrup's The C++ Programming Language 4th edition, in section 3.3.4 Suppressing Operations, it says (emphasis mine):

Using the default copy or move for a class in a hierarchy is typically a disaster: given only a pointer to a base, we simply don't know what members the derived class has, so we can't know how to copy them.

Could anyone please provide a small example of this? Shouldn't the copy/move already be implemented if we are working with a pointer only to a base class?

Edit:

After I read the link provided by Igor Tandetmik, I found this (look at the "treacherous case") which gives a very clear answer to my question, on a different question about Object Slicing.

BobMorane
  • 3,200
  • 1
  • 15
  • 38
  • [Object slicing](https://en.wikipedia.org/wiki/Object_slicing) – Igor Tandetnik Jun 19 '17 at 23:54
  • @IgorTandetnik Good source. If you want to put that into an answer, I am willing to accept it. – BobMorane Jun 20 '17 at 11:24
  • @gsamaras @BaumMitAugen It is not a duplicate at all, even though a part of the above link gives an explanation illustrating where the `delete` keyword can be useful (without ever mentionning it). – BobMorane Jun 21 '17 at 12:04

0 Answers0