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From: "Russ Cox" <rsc@swtch.com>
To: "Fans of the OS Plan 9 from Bell Labs" <9fans@cse.psu.edu>
Subject: Re: [9fans] wait hang
Date: Mon, 18 Dec 2006 11:40:37 -0500	[thread overview]
Message-ID: <ee9e417a0612180840g214943fcwd8212451704f0d03@mail.gmail.com> (raw)
In-Reply-To: <5ff2e8b65c65f83c1d9ac6caefd67b1e@coraid.com>

> the kernel fix does indeed keep
>         ; for(i in `{seq 1 $n}){>/dev/null echo fu&}
>         ; for(i in `{seq 1 $n}){>/dev/null echo fu&}
> from hanging.
>
> however, i think the fix to rc might be in error.  if i do this
>
>         #!/bin/rc
>         cmd1&
>         cmd2&
>         wait
>
> shouldn't that wait for both processes?  for example, on an older
> rc, from this script
>
>         #/bin/rc
>         date
>         sleep 15 &
>         sleep 30 &
>         wait
>         date
>
> i get
>
>         Mon Dec 18 10:57:43 EST 2006
>         Mon Dec 18 10:58:13 EST 2006
>
> whereas with the rc from friday, i get
>
>         ; 8.out
>         broken! date ; sleep 15 & sleep 30 & wait ; date
>         Mon Dec 18 11:00:33 EST 2006
>         Mon Dec 18 11:00:33 EST 2006

You're right.  I forgot about "wait".
I reverted the change to rc.

Note that if you add "wait" to your hanging example
it will not necessarily wait for all of the echos, only
the first 128 or so.

Russ


  reply	other threads:[~2006-12-18 16:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-12-18 16:01 erik quanstrom
2006-12-18 16:40 ` Russ Cox [this message]
2006-12-18 19:05   ` erik quanstrom
2006-12-18 19:23     ` Russ Cox
2006-12-18 20:00 erik quanstrom
     [not found] <db450a2ec40aeb8284b66f00407cb1cb@coraid.com>
2006-12-18 20:06 ` Russ Cox
2006-12-18 20:45 erik quanstrom
2006-12-20  3:55 erik quanstrom

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