simple UNIX_FD pass test?

[Lawrence D'Oliveiro]

On Mon, 12 Nov 2018 10:18:52 -0500, Felipe Gasper wrote:

> Is there maybe a built-in (or systemd) method call that always returns
> unix FDs or some such?

Open a file <https://linux.die.net/man/2/open>?

Open a pipe <https://linux.die.net/man/2/pipe>?

Duplicate a file descriptor <https://linux.die.net/man/2/dup>,
<https://linux.die.net/man/2/dup2>, <https://linux.die.net/man/2/dup3>?

Random other things <https://linux.die.net/man/2/socket>,
<https://linux.die.net/man/2/inotify_init>,
<https://linux.die.net/man/2/epoll_create>?

Very likely other things here <https://linux.die.net/man/2/> that I’ve
missed.