Re: expr ... and `expr ...` return different results on QNX 4.2.5

[Pavel Roskin]

Hello!

> > expr a : '\(a\)'
> > echo $?
> > b=`expr a : '\(a\)'`
> > echo $b,$?
> >
> > Gives:
> >
> > a
> > 1
> > a,0

David, could you please test this:

b=`false` || echo Ok

It should print "Ok". If it doesn't, we are in trouble.

> Sorry, I was already inefficient I guess.  It's the same bug as ASh's
> one reported by Pavel.

It's a different bug. With ash, you shouldn't rely on $? after assignments
_unless_ backticks are used. In this case, you cannot rely on $? _if_
backticks are used.

Unfortunately, the later is hard to eliminate. There are many constructs
of this kind in config.status, e.g.

  ac_file_inputs=`IFS=:
    for f in $ac_file_in; do
...
      esac
    done` || { false; exit; }

I'm afraid that Autoconf will have to reject QNX's shell. It's hard to
work around this kind of shell braindamage :-(

Regards,
Pavel Roskin