-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Thursday 09 July 2009, Gottlob Frege wrote:
On Thursday, July 9, 2009, Frank Mori Hess <frank.hess@nist.gov> wrote:
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I wonder if it might be better/possible to have a shared_ptr<T> that didn't assume its corresponding "raw" pointer type was T* but rather T. For example, what is now a shared_ptr<int> would be specified as a shared_ptr<int*>. The motivation would be to allow support for other classes as the "raw" pointer type. For example, I might want to have a shared_ptr<monitor<T*> > where the monitor<T*> has an operator->() which does automatic locking/unlocking of a mutex before/after forwarding the operator->() to the plain T pointer.
I don't think lock/unlock on each -> call is typically a good idea. x = p->x; y = p->y; That's 2 lock unlock sequences instead of one. Inefficient and what if y changes after you read x? It hides the locking too much, potentially leading to abuse and mistakes.
My monitor_ptr also supports scoped locks, so multiple calls can be made into the object with one lock/unlock: http://www.comedi.org/projects/libpoet/boostbook/doc/boostbook/html/poet/mon... e.g: monitor_ptr<X> mp; { monitor_unique_lock<monitor_ptr<int> > lock(mp); //locks mutex lock->f();// calls X::f lock->g(); }// lock destruction unlocks mutex However, I was hoping to discuss a generalization of shared_ptr more, I mainly brought up monitors as a motivating example. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEARECAAYFAkpWOiYACgkQ5vihyNWuA4VUTACg4MtjHL+bPqwLH/1qjp7YzKP1 TgIAn3dm4chUiv2iqgpi+L+gIUlsiMRq =kKfs -----END PGP SIGNATURE-----