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Re: Semantics of copying mutex/rwlock

In article <>,
Sad Clouds  <> wrote:
>I've seen people state that making a copy of a mutex/rwlock and then
>using that copy will give undefined results. Just trying to understand
>why that happens.
>As far as I know, NetBSD pthreads man pages don't talk about how
>locking primitives are implemented and the result of copying them.
>I mean, maybe it's conventional wisdom that you shouldn't make a copy
>of a mutex, but it seems logical to think that if you have a mutex and
>you know no threads are using it, then 
>memcpy(&new_mutex, &old_mutex, sizeof(pthread_mutex_t))
>and having all threads use new mutex should be OK?

Why do it in the first place? What are you doing with the old mutex?


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