Re: NSSound Code Review

[David Chisnall]

On 29 Jul 2009, at 16:56, Wolfgang Lux wrote:

> David Chisnall wrote:
>
> > Note that this is deprecated on Cocoa - Cocoa applications are  
> > always multithreaded because Cocoa uses a few threads internally.   
> > This also eliminates problems where people are spawning threads  
> > using the POSIX or Mach APIs (in their own code or in libraries)  
> > which don't trigger the notification.  On Cocoa, since 10.2 if I  
> > remember correctly, but possibly earlier, isMultithreaded always  
> > returns YES.
>
> Don't know what makes you believe this. I just tested it on Tiger  
> and Leopard and both return NO by default. Most Cocoa applications  
> on my machine run with a single thread. Maybe you have some  
> utilities like Unsanity's application enhancer running on your  
> machine which start those secondary threads.

Hmm, that's interesting.  The documentation appears to have been  
updated to clarify that that it now only reflects whether the use has  
spawned an NSThread, not whether the application is actually  
multithreaded.  Cocoa, internally, still runs in multithreaded mode  
all of the time, however, and does not rely on this notification.   
There are a number of related changes, for example DO proxy objects in  
OpenStep can only be used from one thread unless explicitly set as  
shareable, while Cocoa makes this the default in recent versions.

If you spawn a POSIX (or Mach) thread in OS X and make Cocoa calls  
from this, without ever sending a notification informing the framework  
of this, then things work correctly.  I do not believe that this is  
yet the case in GNUstep, but it ought to be.

David