Re: parallel autotest [2/3]: Implement 'testsuite --jobs'.

[Ralf Wildenhues]

Hi Eric,

* Eric Blake wrote on Mon, Oct 06, 2008 at 04:43:45PM CEST:
> Eric Blake <ebb9 <at> byu.net> writes:
> > 
> > > +if test $at_jobs -ne 1 &&
> > > +     rm -f "$at_job_fifo" &&
> > > +     ( mkfifo "$at_job_fifo" ) 2>/dev/null &&
> > > +     exec AT_JOB_FIFO_FD<> "$at_job_fifo"
> > 
> > Is exec n<> portable?  Yes, POSIX specifies it, but I haven't seen it used
> > anywhere else in autoconf.  I guess we commit it now, and if it is not
> > portable, we wrap it inside an eval alongside the mkfifo check as a reason
> > to skip the parallel testing.
> 
> Unfortunately, it is NOT portable.

Thanks for checking; and: sigh.  That will require quite a bit of
retesting, I'm afraid.

Oh well.  Can we work around it for now by detecting the Cygwin failure
easily (thus disabling parallel tests there)?

> As a result, the parallel tests invariably fail:

> +./micro-suite: line 1703: read: read error: 0: Communication error on send

Interesting, it didn't do that when I tested it (quite a while ago).

> Can we work on refactoring this into two fd's both visiting the same FIFO, 
> one 
> for writing tokens, and the other for reading tokens, rather than using <>?

Yes, that's one idea I'd like to work on (or be beaten to ;-)
Unless you plan to cut a release soon, it wouldn't be my very
next thing to do though.

Thanks,
Ralf