On Wed, Mar 02, 2005 at 04:08:38AM +0000, hv@[...].org wrote:
>  Hmm, locking a 'refcount--' doesn't make much sense to me: if two threads
>  both do this at the same time, they'll still then both try to free the
>  structure. But I see that op_free() does essentially the same thing,
>  which confuses me. Can anyone explain how that makes sense?

I haven't been following this thread closely (I don't even know what a
trie is), but I'll chip in anyway.

In the op_free() case, an op tree may be shared by CVs from differnt threads.
The head of the tree contains an OP refcnt, so OP_REFCNT_LOCK is used to
lock it before decrementing it.

On the other hand, using OP_REFCNT_LOCK to lock an SV doesn't seem to make
much sense (but as I said, I havn't been paying close attention).

Dave.

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