From mboxrd@z Thu Jan  1 00:00:00 1970
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
In-reply-to: Your message of "Fri, 04 Sep 2009 00:47:18 PDT."
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From: Bakul Shah <bakul+plan9@bitblocks.com>
Date: Fri,  4 Sep 2009 07:41:09 -0700
Message-Id: <20090904144110.10C345B4B@mail.bitblocks.com>
Subject: Re: [9fans] "Blocks" in C
Topicbox-Message-UUID: 64afa7c0-ead5-11e9-9d60-3106f5b1d025

On Fri, 04 Sep 2009 00:47:18 PDT David Leimbach <leimy2k@gmail.com>  wrote:
> On Fri, Sep 4, 2009 at 12:11 AM, Bakul Shah
> <bakul+plan9@bitblocks.com<bakul%2Bplan9@bitblocks.com>
> > wrote:
>
> > But this has no more to do with parallelism than any other
> > feature of C. If you used __block vars in a block, you'd
> > still need to lock them when the block is called from
> > different threads.
> >
> I just wrote a prime sieve with terrible shutdown synchronization you can
> look at here:
>
> http://paste.lisp.org/display/86549

Not sure how your program invalidates what I said.  Blocks do
provide more syntactic sugar but that "benefit" is independent
of GCD (grand central dispatch) or what have you. Given that
__block vars are shared, I don't see how you can avoid locking
if blocks get used in parallel.