-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Tuesday 29 April 2008 02:18 am, Daniel Frey wrote:
I think there are cases not caught by the current assert condition:
struct A : boost::enable_shared_from_this<A> {};
int main() { boost::shared_ptr<A> pa; { A a; pa = a.shared_from_this(); boost::shared_ptr<A> pa2( &a ); // here, first 'pa2' and then 'a' goes out of scope! } // now 'pa' still exists and points to a deleted object }
You've already created undefined behavior just by passing ownership of a stack object to a shared_ptr with the default deleter, which is in no way specific to enable_shared_from_this.
What do you think of the following condition:
BOOST_ASSERT( _weak_count.use_count() == 0 || _shared_count.use_count() == 1 );
There is no shared_ptr requirement that a user is forbidden to create dangling shared_ptr if they choose to. I don't think owning an enable_shared_from_this derived object should impose any additional constraints on shared_ptr usage. Adding additional checks to enforce shared_ptr best practices seems like an independent concern from esft. It could be done in an independent class, and might make decent example for sp_accept_owner usage. - -- Frank -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFIFyXs5vihyNWuA4URAn3RAKCT385xl5617h1uE+OmqrsItL6TdgCdGPW1 Tg6I9VXEsRVxQrLVFYQuCIM= =7whB -----END PGP SIGNATURE-----