Re: Why does "mapfile -d delim" (delim != '\n') use unbuffered read?

[Chet Ramey]

On 5/4/21 10:06 AM, Koichi Murase wrote:

> > Let's take a step back. I think we can make the code simpler and still
> > handle all the cases we need to. I don't think tape devices are worth
> > worrying about.
> >
> > The issue with the BSDs and terminal devices is that the current code
> > only checks for -1/ESPIPE, but they return a different value for errno
> > (EINVAL? I forget.) I believe AIX returns something else. Rather than
> > check for specific errno values, we can just decide not to buffer input
> > if lseek fails for any reason.
>
> OK.  I agree with this direction.  The attached file is my current
> patch for (2) and (3) with the above strategy (no check for ESPIPE).

I used a combination of the simpler approach and the fstat/S_ISREG
strategy you suggested in your previous email.


> By the way, I'm sorry but there was a typo in my previous mail:
>
> > (3) Suggestion: change the order of `run_callback' and `zsyncfd'?
> >
> > I noticed that `zsyncfd' is called before `run_callback':
>
> This is a typo of "`zsyncfd' is called **after** `run_callback'".

I don't think this will make much of a difference -- it never has,
and the state of the file during the callback's execution isn't
defined -- but I made this change. Changing entrenched behavior is
always a tricky business. We'll see how it goes.


--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/