boost.threads [was RE: [boost] Re: sockets /network programming Requirement

From: williamkempf_at_[hidden]
Date: 2001-08-07 14:57:04

--- In boost_at_y..., duncan_at_s... wrote:
> williamkempf_at_h... () wrote:
> 
> > A singleton is a design pattern for a type with controlled
> > construction semantics, typically used to insure only
> > one instance may be created
> 
> So what's the atypical usage? I always thought it was a design 
pattern 
> to ensure a type only has one instance and to provide a point of 
access 
> to that one instance.

From GoF, under Consequences, item 4:  Permits a variable number of 
instances.  The pattern makes it easy to change your mind and allow 
more than one instance of the Singleton class.  Moreover, you can use 
the same approach to control the number of instances that the 
application uses.  Only the operation that grants access to the 
Singleton instance needs to change.

So, that's the atypical usage.

Bill Kempf