Re: thread question

[Aurelien]

Le jeudi 27 décembre 2001, à 07:22 PM, Richard Frith-Macdonald a écrit :

> No .... the lock needs to be created beforehand. You could have a 
> single global lock
> created at the start of your program, and do something like this.

Ah !

Pardon me, I don't understand a word of the following code:
> - (void) doSomething
> {
>   static NS(Recursive)Lock *aLock = nil;

You can declare a static variable (that is, a class variable, then ?) 
inside a method ???

>   if (aLock == nil)
>     {
>       [globalLock lock];
>       if (aLock == nil)

Hey ! we already know that aLock is nil !

>         {
>           aLock = [[NS(Recursive)Lock alloc] init];
>         }
>       [globalLock unlock];
>     }

Do you mean, that we must obtain a lock to allocate the lock ? That 
sounds logical to me. Why wouldn't we simply create the lock in the 
object's init method ? Maybe you suggest that this is more "lazy", ie we 
don't necessarily *have* to have an NSLock associated with the *whole* 
object, hence the need for a globalLock ?

>   [aLock lock];
>   // do something
>   [aLock unlock];
> }
>
>
> > Now, what I don't understand is the use in java of the wait(), 
> > notify () and notifyAll() methods.
>
> There is really no direct equivalent ... but NSConditionLock should 
> cover most of this I think.

Right, I forgot that one ! Should be OK.

Thanks Richard,

Aurélien