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Date: Mon, 11 Nov 1996 09:15:02 -0500 (EST)
From: "Ron G. Minnich" <rminnich@Sarnoff.COM>
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To: "Marc G. Fournier" <scrappy@ki.net>
cc: Tim Pierce <twpierce@bio-3.bsd.uchicago.edu>, hackers@freebsd.org
Subject: Re: semaphores/shared memory
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On Mon, 11 Nov 1996, Marc G. Fournier wrote:
> On Sun, 10 Nov 1996, Tim Pierce wrote:
> > No, sorry, even this shouldn't be necessary.  Have the server
> > create the semaphore and increment its value to 1.  Then have each
> > client wait until the semaphore becomes 0.  When the data has been
> > written to shared memory, have the server decrement the semaphore
> > to zero, which will unblock all of the clients.
> 	Okay, now bearing in mind that I'm looking at the examples as
> presented in "Unix Network Programming" by W. Richard Stevens...how
> do n clients signal back to the server that its finished with the data
> and can send up the next set of data?

have the lock lock a bitmask. Then use fdsets to set/clear bits. Client 
'n' does and FDSET(n, ready_mask). I've done this -- works fine. server 
should initially zero the mask.

ron