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Re: Intriguing error with arithmetic evaluation
From: |
Stephane Chazelas |
Subject: |
Re: Intriguing error with arithmetic evaluation |
Date: |
Tue, 23 Aug 2016 17:15:25 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
2016-08-12 14:22:32 -0400, Chet Ramey:
[...]
> The relevant change was probably the change in the set of commands to which
> `set -e' applies. The (( command (among others) was added to that list
> in bash-4.1. The change was the result of Posix changing the semantics
> of the errexit option and expanding its scope from simple commands to
> all commands.
>
> The (( command returns 1 if the expression evaluates to 0. When `level' is
> 0, level++ returns a 0 value, and (( returns a status of 1.
[...]
POSIX doesn't specify ((...)) (explicitely leaves it
unspecified), so is out of POSIX scope anyway.
It was introduced by ksh88.
There and in ksh93 (but not pdksh nor zsh)
ksh -c '((0)); echo X'
outputs X
For:
ksh -ec '[[ -z . ]]; echo X'
I see a difference between ksh88 (Solaris /usr/bin/ksh) which
displays the X (like bash<4.1) and ksh93 (u+) which doesn't any more.
In any case, I'd go with Greg's advice to avoid "set -e".
--
Stephane
- Re: Intriguing error with arithmetic evaluation, (continued)
- Re: Intriguing error with arithmetic evaluation, Chet Ramey, 2016/08/12
- Re: Intriguing error with arithmetic evaluation, L. A. Walsh, 2016/08/15
- Re: Intriguing error with arithmetic evaluation, Greg Wooledge, 2016/08/15
- Re: Intriguing error with arithmetic evaluation, L. A. Walsh, 2016/08/21
- Re: Intriguing error with arithmetic evaluation, Chet Ramey, 2016/08/21
- Re: Intriguing error with arithmetic evaluation, L. A. Walsh, 2016/08/21
- Re: Intriguing error with arithmetic evaluation, Chet Ramey, 2016/08/16
- Re: Intriguing error with arithmetic evaluation, L. A. Walsh, 2016/08/16
- Re: Intriguing error with arithmetic evaluation, Greg Wooledge, 2016/08/16
- Re: Intriguing error with arithmetic evaluation, Chet Ramey, 2016/08/16
- Re: Intriguing error with arithmetic evaluation,
Stephane Chazelas <=