What's the most reliable way to prohibit a copy constructor in C++?

Question

Sometimes it\'s necessary to prohibit a copy constructor in a C++ class so that class becomes \"non-copyable\". Of course, operator= should be prohibited at the

Answer 1

As other answers suggest something else, and doesn't really attempt to answer the question, so here is my attempt:

So which approach is better? It depends on how you define prohibit copy?

If you want to prevent others (only non-friend classes and functions) from copying while allowing friends and member-functions to copy, then second approach is the way to go.

If you want to prevent everyone (friends, non-friends, member-functions) from copying, then first approach is the only correct solution.

Note that the second approach does not prevent friends and member-functions from copying (that is, from calling the copy-functions). ¹

^{1. If you don't properly define them in the second case, then copy wouldn't work, as expected, but that is a different thing altogether. But the point is that second case doesn't prevent from calling the copy-functions. The compiler wouldn't generate any error message.}