On Friday, August 23, 2013 22:20:21 Timon Gehr wrote: > On 08/23/2013 10:08 PM, Peter Alexander wrote: > > On Friday, 23 August 2013 at 20:04:28 UTC, H. S. Teoh wrote: > >> What's the problem with const again? > > > > I'm thinking mainly of const postblit, and the ramifications of solving > > that. > > What problem does const postblit have that a const constructor does not > have?
A copy constructor creates a new object from scratch, so it doesn't modify anything, and creating it as const is fine. postblit on the other hand does a memcopy of the object first and then modifies select portions of the copy. When constructing a const or immutable object, that would mean that you have to modify a const or immutable object in order to mutate the portions that the postblit is supposed to be mutating. We need a way to construct a copy rather than copy and mutate, so AFAIK, we basically need to add copy constructors to solve this problem. - Jonathan M Davis
