From: "Russ Cox" <rsc@swtch.com>
To: "Fans of the OS Plan 9 from Bell Labs" <9fans@cse.psu.edu>
Subject: Re: [9fans] Semaphores
Date: Sun, 22 Oct 2006 19:21:37 -0400 [thread overview]
Message-ID: <ee9e417a0610221621h2a35a87bha7ff9c33f2d1c3b7@mail.gmail.com> (raw)
In-Reply-To: <7871fcf50610221605y124a0b9dnccd7e3e420a0ad03@mail.gmail.com>
You can't use signals for wakeup on Plan 9.
There is no sigprocmask to turn off note delivery
(so no atomic sections) and no sigsuspend
(so no atomic check a condition and go to sleep).
Instead you need to use rendezvous(2).
For a good example of using rendezvous to
do sleep and wakeup, read the implementation
of qlock, in /sys/src/libc/9sys/qlock.c. Everywhere
it says (*_rendezvousp) just pretend it says
rendezvous. (The thread library replaces the
rendezvous that qlock uses, but that detail is
not relevant here.)
Russ
next prev parent reply other threads:[~2006-10-22 23:21 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-22 23:05 Joel Salomon
2006-10-22 23:21 ` Russ Cox [this message]
2006-10-22 23:29 ` Steve Simon
-- strict thread matches above, loose matches on Subject: below --
2002-01-25 14:53 [9fans] semaphores Russ Cox
2002-01-16 7:48 nigel
[not found] <rsc@plan9.bell-labs.com>
2002-01-16 3:44 ` Russ Cox
2002-01-16 3:54 ` Scott Schwartz
2002-01-16 11:14 ` Boyd Roberts
2002-01-16 15:47 ` Ronald G Minnich
2002-01-25 10:30 ` Ralph Corderoy
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