[boost] singleton_ptr

From: Jason Hise (chaos_at_[hidden])
Date: 2005-07-16 13:21:34

Background:
Since the first version of my singleton library was rejected, I have 
been designing a new singleton library from the ground up.  I feel that 
this is necessary because the first version was not designed with the 
concerns of threading in mind, and such concerns cannot easily be 
addressed efficiently as an afterthought.  The new design should 
hopefully be able to handle threading effectively without introducing 
any overhead for the single threaded model.

Question:
With the new design, I am adding a policy to control exactly what 
happens if creation is attempted while the singleton instance exists.  
The options thus far include throwing an exception, doing nothing, or 
destroying and recreating the singleton, depending on the policy used.  
Does it make sense to have a similar policy for what happens when 
attempting to destroy an already destroyed instance?  I can think of a 
few options that would make sense, such as doing nothing, throwing an 
exception, asserting, or creating the instance so that it can be 
re-destroyed, but I do not know if these would actually be useful enough 
to justify a point of customization.  Thoughts?

-Jason