Re: [9fans] thread confusion

[Russ Cox <rsc@swtch.com>]

> if I first close one randomly chosen end of the pipe,
> and then do a zero-length write at the other end and
> then close that end, it works.

By it works I assume you mean you get a zero-length
read out the other end.  But that's because you did a
zero-length write, not because the pipe is signaling EOF.

> It also works if I first close one end of the pipe,
> and then do the zero-length write and close at the
> other end.

Pipes are symmetric so this is good.

> is this a correct procedure, or would another be preferred?

What doesn't work?  Can you post a small test program
that doesn't make a blocked read fail when the other
end of the pipe is closed?  Again, it sounds like you're
not closing all the references to one end of the pipe.
If multiple programs have references to a pipe end,
they *all* need to close them.  Make sure that the
proc running tlsClient doesn't have a reference too.

> the question is how to start and reset the timer.

It depends how granular this timer is.  If we're talking
about something large like seconds, then it is reasonable
to have the timer proc just poll the channel with nbrecvp
for new work or cancellations after it ticks off each second.

Your alternate approach, with a tick stream, is also reasonable.

No matter which you use, the return channels that the timer
proc writes to should be buffered so that the timer proc never
blocks writing to them.

Russ