-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Monday 28 July 2008 10:29 am, Daniel Frey wrote:
On Mon, 2008-07-28 at 08:52 -0400, Frank Mori Hess wrote:
I don't think the zero-argument call to make_shared resolves to the variadic template, see the make_shared.hpp file.
I've seen that, but:
a) I don't understand what the "new T()" vs. "new T" issue is - and there seems to be nothing in the code which explains that. It does use new T(), which should also work for new T( Args... ) if Args is a zero-sized parameter pack, shouldn't it?
b) Looking at N2352 and N2691, there should be only one make_shared. Boost vs. GCC already shows that looking at a concrete implementation is not enough. Question is, what is/should be guaranteed by the standard. If nothing like this is guaranteed (probably because it's simply too late?), I would end up with non-portable code. Even then I would be interested in whether or not you, Peter, etc. think if something like that should be at least targeted for TR2...
I'm just saying the friend declaration might need to be simply template< typename A > friend std::shared_ptr< A > std::make_shared(); due to the overload for zero arguments in make_shared.hpp. I should mention I didn't notice before that you were actually using std:: instead of boost:: and I'm not actually familiar with the gcc 4.3 implementations.
d) Besides the use case above, what do you think about using this pattern to allow shared_from_this to be called in the ctor? Is this possible? Would it be useful?
Do you mean something like a more generic version of deconstruct_ptr: http://www.comedi.org/projects/thread_safe_signals/libs/thread_safe_signals/... except it would have the benefits provided by make_shared, and allow a class to force its use via private constructor/friendship? It seems like it could be useful. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFIjhLN5vihyNWuA4URApSzAKDEuIXm4wgkjzN+U/gzyY+mTSOhEACgoiLw szeR3hdmp+4URvtK6v5mZ28= =j4Vs -----END PGP SIGNATURE-----