On Monday 17 March 2008 01:42, Frank Mori Hess wrote:
On Monday 17 March 2008 01:36, Frank Mori Hess wrote:
The implementation I've got in mind (haven't actually tried it yet) would work as follows. I'd add two shared_ptrs to enable_shared_from_this, call them "internal_shared" and "external_shared". external_shared would be assigned the external shared_ptr which first takes ownership of *this. internal_shared would be initialized with the "this" pointer, and a custom deleter which would reset external_shared. internal_shared would be reset right after external_shared is initialized (when an external shared_ptr
Sorry for the repeated replies to myself (I probably shouldn't be posting past 2 AM), but I think the answer is to swap internal_shared with the external shared_ptr taking ownership before resetting internal_shared. Then everything is a copy of the original internal_shared, and external_shared preserves the user's deleter.
takes ownership of *this). Any calls to shared_from_this() that occur prior to an external shared_ptr taking ownership of *this (such as in the constructor) would get a copy of internal_shared.
Hmm, actually nevermind. This scheme isn't good enough yet, as I'd also want a weak_ptr copy of internal_shared to recognize the case where the object is still being kept alive by a copy of external_shared.
-- Frank