Frank Mori Hess wrote:
On Sunday 25 February 2007 12:07 pm, Peter Dimov wrote:
Now that I think about it, it can be implemented both ways. A slot that requires an explicit lock() before operator() would still need the .track. A slot that throws bad_weak_ptr from operator() would not. This brings us back to the problem of autodisconnects only happening on calls. :-/ It doesn't have to be either-or, though.
Yes, I was assuming an explicit lock(), and perhaps exposing the tracked object list read-only for efficiency, which would allow multiple slots to be locked at once without creating a separate container for each slot.
I think I prefer: bool expired() const; R operator()( A... ) const; // throws bad_weak_ptr operator() could do alloca() tricks to avoid dynamic allocations. The portable version could use a local array< shared_ptr, K > to catch the common case when the number of tracked objects is no more than K. Hiding a slot behind a bind() or some other adaptor (std::not1, say) would make it invisible to the expired() query, but it will still track its objects within its operator().