Hi All,

The thread "Re: premature dealloc of the datasource of a NSTableView crashes my application" made me think about this problem again.

This is the question I really wanted to ask:

I have an object X that is alloc/inited on the main thread. This object creates some NSThreads with detachNewThreadSelector:toTarget:withObject, which have object X as their target. At a later point I want to release object X and have it be dealloced on the main thread.

How do I guarantee that object X is dealloced on the main thread?

The problem is this: the NSThread objects retain object X. I have a stop method in object X that sets a 'cancelled' global that the thread objects inspect and they then exit when it turns true. So I send stop and then release on the main thread. The thread objects exit and eventually release object X but the last release, which causes the dealloc, can be on any thread.

I attempted to synchronize the exit of the thread objects' main method using NSConditionLock. The synchronization worked but the dealloc still occurred on a background thread because the release from the NSThread happens after the main method returns.

I also tried to synchronize based on receipt of the NSThreadWillExitNotification. The synchronization succeeded but this also failed because the notification is also sent before the NSThread releases its target.

I couldn't figure out any notification that is sent by the threads that happens after the release of their target or after the die entirely. I couldn't figure out what to wait for.

This question of stopping threads has been mentioned numerous times in the archives but I didn't see this issue addressed.

Any thoughts?


--
Brian Stern
[EMAIL PROTECTED]



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