From mboxrd@z Thu Jan  1 00:00:00 1970
From: doug@cs.dartmouth.edu (Doug McIlroy)
Date: Thu, 10 Jul 2014 08:04:43 -0400
Subject: [TUHS] Excise process from a pipe
In-Reply-To: <20140710045223.GA19076@www.oztivo.net>
References: <201407100249.s6A2nMh3017869@coolidge.cs.dartmouth.edu>
 <20140710045223.GA19076@www.oztivo.net>
Message-ID: <201407101204.s6AC4hKQ026601@coolidge.cs.dartmouth.edu>

In the suggested answer, the code changes but the process survives.

I suspect the answer to my original question is no, but I know only a tiny
fraction of the cumulative API of the extended Unix family.

Doug

>> Was there ever a
>> flavor of Unix in which a process could excise itself
>> from a pipeline without breaking the pipeline?
>
> If in the middle of a pipeline, all I can think of is:
>
>       close fd 0 and fd 1
>       dup() read end of pipe 1 to be stdin (fd 0)
>       dup() write end of pipe 2 to be stdout (fd 1)
>       exec("/bin/cat")