Re: NSThread Comparisons

[Richard Frith-Macdonald]

On 4 Jan 2008, at 00:11, Justin Kendrick wrote:

> I'm writing a class which needs to determine the current thread

[NSThread currentThread]

> and get an object tied to that thread.

id threadSpecificObject = [[[NSThread currentThread] threadDictionary]  
objectForKey: @"KeyForMyObject"];

>  I'd like to use an NSDictionary keyed by an NSThread object, but  
> NSThread instances not copyable (and I can't find any good  
> documentation on how NSDictionary matches non-NSString keys  
> anyway).  Beyond that, I thought that I might use an NSValue created  
> with valueWithUnretainedObject:, but that feels really hackish.

Not sure why you want to use a dictionary keyed on a thread ... the  
above line of code gives you an object stored in the thread dictionary.
Each thread has a dictionary to store thread-local objects, which  
seems to be exactly what you need.

> For that matter, is there a one-to-one mapping between NSThread  
> instances and Posix threads -- that is, can I compare two NSThread  
> pointers and conclude that the NSThread instances do or do not  
> represent the same thread?

Yes you can compare thread pointers ... each NSThread instance  
represents a different thread.