Re: [PATCH v3 2/2] Use O_IGNORE_CTTY where appropriate

[Paul Eggert]

On 6/10/23 12:13, Sergey Bugaev wrote:

> O_IGNORE_CTTY is not about
> acquiring a ctty if you don't yet have one (that never happens
> implicitly on the Hurd), but about (re)opening your current ctty.

OK, I'm starting to see the distinction now.



> I don't know whether any programs actually care about this ctty
> feature. Presumably users care? -- as I understand it, this is
> intended to be used with job control in the shell

If so, it's a well-kept secret, as Bash doesn't use O_IGNORE_CTTY.

The only program I know of that uses O_IGNORE_CTTY is Emacs, and it's 
for what appears to be relatively minor optimization when it is opening 
a file that is a tty. On non-Hurd platforms Emacs instead uses setsid to 
remove the controlling tty entirely (since the notion of controlling 
terminal doesn't mix well with how Emacs operates).