Re: precmd: write error: interrupted

[Yuri D'Elia <wavexx@users.sourceforge.net>]

On 04/25/2013 08:16 PM, Bart Schaefer wrote:
> On Apr 25,  6:47pm, Yuri D'Elia wrote:
> }
> } I still have the error, as I didn't find any way to silence it (braces
> } around print do not work?!).
>
> That's curious, but try using parentheses to force a fork and redirect
> the stderr of the subshell.

This, of course, works. But I wouldn't want to fork here just to ignore 
the error message.

> } I have no idea which write is actually failing in that function (I
> } suppose it's some "fputs" in bin_print).
>
> strace should be able to show you what bytes are being written, which
> would narrow it down.

not really, apart from the "write error:" which I already knew. But 
there are only two possible points in bin_print, and I'm using the 
"unformatted" case.

> } 2) Why "precmd() { { print "HELLO" }>&- 2>&-; } doesn't suppress the
> } error in this case?
>
> It's not the same error.  Try 2>/dev/null instead of 2>&- ... with the
> stderr closed, you're actually getting a second error from outside the
> braces, about not being able to write the first error from inside!

You are right. I pasted one of my numerous trials in an attempt to 
exploit the EBADF errno.

But anyway:

precmd() { { print x } 2>/dev/null }

still doesn't suppress the error.

By looking at bin_print, zwarnnam is used.

In the "normal output case" (Src/builtin.c:6310) there's an explicit 
test for >&- redirection of stdout, and that's it. I see nothing in 
zwarnnam except for the noerrs global that would allow error redirection 
to work in lists.

Maybe there's a builtin to force "noerrs" instead?