On 9/1/21 2:23 PM, Robert Elz via austin-group-l at The Open Group wrote:
> Date: Wed, 1 Sep 2021 19:04:12 +0100
> From: Harald van Dijk <a...@gigawatt.nl>
> Message-ID: <837d3b5b-ac61-98eb-2741-d667a78e2...@gigawatt.nl>
>
> | Is there any statement that overrides the general definition to
> | explicitly make this unspecified? If not, the general definition applies
> | and $? must expand to 0 both times it appears on line 2.
>
> Perhaps as currently written that's correct, but if so, the standard
> probably needs to be updated, as it is fairly clear that shells which
> set $? as each command substitution finishes have always existed (in
> fact, that might have been what the original Bourne shell did, I haven't
> checked) and the standard should allow for that.
Given the following:
(exit 42)
a=$? b=`false` b=$?
echo $? $a $b
Bash prints 1 42 1.
The original (v7) bourne shell and the rest of the research line through v9
prints 1 1 (b is set to the empty string). That implies that it executes
the assignment statements in reverse order, in addition to carrying $?
through the sequence of assignments.
The SVR4.2 shell prints 1 42 1. I imagine the rest of the SVR4 line sh is
the same.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU c...@case.edu http://tiswww.cwru.edu/~chet/
