[Toybox] [PATCH] setsid: document -w.

[Rob Landley]

On 1/10/20 6:17 PM, enh via Toybox wrote:
> -w was added recently. The change in behavior so we now always fork
> means that it's needed in more cases too: other implementations of
> setsid(1) only fork if getpgrp() != getpid(). This broke a script, which
> is what made me notice the missing help.

I can change how it works? But I thought the point is it wanted a _new_ session
leader. (You'd have to exec setsid in order to inherit the previous session
leader, is this a common thing to do? Otherwise you get a new pid...)

> This seems to have been an accidental change, and is contrary to what
> the util-linux setsid(1) man page says: "The command calls fork(2) if
> already a process group leader.  Otherwise, it executes a program
> in the current process", but whether we change our behavior or not, we
> should document the new option.

My logic was "you just ran a new command, it has a new pid, that's the common
case". If "exec setsid" is the common case, I can add another test? (Does mksh
setsid() children after fork() by default?)

Sorry, I'm unclear on what "success" looks like here with some of the stranger
inputs.

Rob