Thorsten Ottosen wrote:
Kazutoshi Satoda skrev:
Do you think passing a temporary auto_ptr should be allowed to allow passing a returned auto_ptr?
Oh yes. Generic libraries in particular needs to be useable rather than over-encapsulated.
(Sorry for this late response.) I understood dropping pass-by-value version will decrease the usability in the case where returning auto_ptr from a function and passing another argument as rvalue. But I think it can be justified for the exception-safety as more important aspect, as the FAQ currently says for raw-pointer versions. On the other hand, I don't see what the problem is about the term "over-encapsulated". Could you please explain more about the concrete problem with it?
If there is a real need for operations with the strong guarantee, I think we should add them with the following signature:
strong_push_back( std::auto_ptr<U>&, ... );
albeit they can be implemeted by a user because you have access to the underlying container with .base():
std::auto_ptr<U> ptr( ... ); cont.base().push_back( ptr.get() ); ptr.release();
I didn't know about the base() function. My original motivation can be satisfied with the latter workaround. Thank you. However, I still think providing the strong guaranteed version as the default is better in general. For function calls passing a single argument like push_back(), calling like push_back(returning_auto_ptr(...).release()) seems no-less usable and more expressive about what is happening. -- k_satoda