c++ - Correct usage(s) of const_cast<>

Question

As a common rule, it is very often considered a bad practice to use const_cast<>() in C++ code as it reveals (most of the time) a flaw in the design.

While I totally agree with this, I however wonder what are the cases were using const_cast<>() is ok and the only solution.

Could you guys please give me some examples you know/you encountered ?

Thank you very much.

Answer 1

it is pretty much designed to be only used with legacy APIs that are not const correct i.e. with a function you can't change that has non const interface but doesn't actually mutate anything on the interface