RFC: singletons and memory management

[Leo Franchi]

On Sep
> What happens is that if you call "delete Singleton::instance()", then
> the object pointed to by s_instance is freed, but s_instance is never
> reset to zero.  So the next time you call Singleton::instance(), it
> will hand back the memory location where the object used to be, and
> you'll get a segfault.  You need to call a static Singleton::destroy()
> member to set the s_instance pointer to zero after the object is
> deleted, so that the next time Singleton::instance() gets called, it
> will create a new object.  You could also use a "smart" pointer like
> auto_ptr or QPointer that automatically set to zero when they're
> deleted, but I personally prefer the static destroy() method.  At any
> rate, the Singleton classes in Amarok should be a little smarter about
> their memory management.


I was responding to eean's point, not yours :) I agree with you, and i  
think we should have some smarter deletions---imho, using QPointers  
would work well too.

leo

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Leo Franchi				(650) 704 3680
Tufts University 2010

lfranchi at kde.org
leonardo.franchi at tufts.edu