Re: [boost] Rationale for shared_ptr/array including both ptr to control and ptr to data in class

Olaf van der Spek wrote:

Ah. BTW, why doesn't shared_array provide size()? IMO it'd be quite useful to have.

The obvious answer, that it doesn't have this information, has already been given, but it's not enough; you could legitimately ask why shared_array doesn't have it, that is, why its constructor doesn't take a size in addition to the pointer. The answer is, well, historical reasons. While the current shared_ptr allows you to easily implement a sized shared_array by storing the size in a deleter, when shared_array was first designed, this was not the case. shared_array was kept a simple reference-counted wrapper over new T[]. shared_ptr then evolved considerably, and shared_array has failed to keep up. So here we are. :-)