[oezi]

Sure, but auto_ptr is different in that copying transfers ownership, while unique_ptr prohibits copying.

[kennu]

But if I understand it right, auto_ptr assignment didn't actually copy the pointer, but instead moved it to a new variable and quietly made the original variable null? And unique_ptr made this operation require an explicit move() call, because the assignment-only style caused too many null pointer bugs.

I'm just curious about this for historical interest.

[oezi]

Yes, it was a design decision of the auto_ptr to have this move semantics and it worked very nicely for us because we used for instance to pass progress monitors down the stack.