Alain D D Williams wrote in <20221229173548.gw16...@phcomp.co.uk>: |On Thu, Dec 29, 2022 at 06:23:09PM +0100, Steffen Nurpmeso wrote: |> Hello. |> |> Name: bash |> Path: /usr/ports/core |> Version: 5.2.15 |> Release: 1 |> |> $ i=10 j=20;echo $(( i += j += i += j ));echo $i,$j |> 60 |> 60,50 |> $ i=10 j=20;echo $(( i += j += i += i ));echo $i,$j |> 50 |> 50,40 | |You are modifying something that is used elsewhere in an expression. \ |I am not |surprised that you do not get what you expect; others might expect \ |something |different. | |At most there should be a note in the documentation that this sort of thing |leads to undefined behaviour -- that is what happens in other languages. | |This is very much not a bug in bash.
I very much disagree. My mailer's $(()) evaluator also does this right. (And busybox's one, if it gets accepted.) |C does it differently. I would not be surprised to see different C \ |compilers |produce different results or different results with different levels of |optimisation. Come on. Be a brave man. --steffen | |Der Kragenbaer, The moon bear, |der holt sich munter he cheerfully and one by one |einen nach dem anderen runter wa.ks himself off |(By Robert Gernhardt)
