Re: Process-Shared Mutex (futex) - What is it good for ?

From: Vladimir Zidar (
Date: Tue Jun 11 2002 - 12:18:39 EST

On Tue, 2002-06-11 at 15:19, Peter Wächtler wrote:

> A-prog: B-prog:
> gets write lock
> write some data
> block on read lock
> write some data
> crashes
> wants an error indication to repair data magically

 B-Prog unblocks, but gets -1, with errno=EPIPE.

> So a crashing A-prog is OK for you, but B should get an indication.
> Could catch a signal (SIGLOST?) returning -1 with errno=LOCKBROKEN
> That would be possible with futex.

 Nice if that *would* be possible. But that IS how nutexes are working

> That is a case for writing data to a file - what about linked lists
> in memory?

 Exactly the same. Nutexes are not related to files in any way (other
than /dev/nutex descriptor, but that's completly different thing).


and have a very nice day !

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