Re: dup(0) fails on Ubuntu 20.04 and macOS 10.15 with 13.0

Mario Emmenlauer <mario(at)emmenlauer(dot)de> writes:
> The idea to switch to dup(2) sounds very good to me. Also, while at it,
> maybe the error message could be improved? The kids nowadays don't learn
> so much about system I/O any more, and if someone does not know `dup()`,
> then the error message is not very telling. It took me a while to under-
> stand what the code was supposed to do. So it may be helpful to add to
> the error message something like "possible the stderr stream is closed,
> this is not supported". What do you think?

Meh ... it's been like that for ~20 years and you're the first one
to complain, so I'm not inclined to make our translators spend effort
on a HINT message. However, we could reword it to the extent of, say,

elog(WARNING, "duplicating stderr failed after %d successes: %m", used);

which at least reduces the jargon level to something that Unix users
should have heard of.

regards, tom lane