5 ms·

Can't copy-on-write achieve the same thing? If you keep a reference count, you can know whether it's safe to mutate the underlying data, or whether you need to

Can't copy-on-write achieve the same thing? If you keep a reference count, you can know whether it's safe to mutate the underlying data, or whether you need to make a copy first.

heavenlyblue 7y ago
Technically copy-on-write is an implementation detail. It may or may not be implemented this way.
- slavik81 7y ago
  I mean that CoW classes like Qt's QStringList do the same data sharing without being immutable.
  - slavik81 7y ago
    Admittedly, it's pretty easy to accidentally make unnecessary non-const accesses in modern C++. An immutable API would certainly avoid a lot of qAsConst casts.