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Date: Tue, 9 Jul 1996 10:22:24 +0900 (JST)
From: Michael Hancock <michaelh@cet.co.jp>
To: "Ron G. Minnich" <rminnich@Sarnoff.COM>
cc: hackers@freebsd.org
Subject: Re: filemalloc etc. for shared memory between processes
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On Mon, 8 Jul 1996, Ron G. Minnich wrote:

> > 	I wonder how one should properly implement locking of memory
> > 	regions in this case. Will appropriate fcntl(2) be
> > 	enough?
> 
> no, you use the fastlock() i posted earlier. fcntl is probably the worst 
> way there is to lock shared regions. You want memory-value-based locking 
> so you can use compare-and-swap (or equivalent).

I read in the New Frontiers book about 4.4bsd semaphores; something like
mset and mclear, but I didn't see any mention of this in the 4.4 deamon
book.

Does the pthreads lib have facilities for locking data structures in
shared memory?

-mike