Re: Singleton as a common area?

FROM : James Hober
DATE : Wed Feb 20 22:03:28 2008

On Feb 20, 2008, at 12:04 PM, Jerry LeVan wrote:

> It seems to me that a singleton object could be used
> to hold lots of global state info and it would be
> easy to instantiate the singleton in each of the
> source files to access the stashed info...
>
> Is this a reasonable way to share info?


Sometimes you just create a single instance of a class.

Other times you enforce that only zero instances or one instance can 
ever be created.  To do this second thing,

http://developer.apple.com/documentation/Cocoa/Conceptual/
CocoaFundamentals/CocoaObjects/chapter_3_section_10.html

Then you can use your singleton,

#import "Foo.h"

[Foo sharedFoo];

which is nice because now you don't have to keep track of instances 
of Foo.  You just get THE instance right from the class method.

The documentation above explains when this is a good way to do things.

James