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Re: bash-4.0 regression: negative return values


From: Jon Seymour
Subject: Re: bash-4.0 regression: negative return values
Date: Mon, 23 Feb 2009 16:25:57 +1100

On Mon, Feb 23, 2009 at 4:03 PM, Mike Frysinger <address@hidden> wrote:
> previous versions of bash would happily accept negative values ( treated as a
> signed integer and masked with like 0xff), but it seems some changes related
> to option parsing has broken that
>
> $ f(){ return -1; }; f
> -bash: return: -1: invalid option
> return: usage: return [n]
>
> POSIX states that the return value is an "unsigned decimal integer":
> http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_24_01
>
> but bash does not say that in the bash(1) man page ...
> -mike
>

For the record, GNU bash, version 3.2.39(20)-release (i686-pc-cygwin)
behaves this way:

> f() { return -1; }; f; echo $?
255

Which, burnt me the other day. I think I prefer the way bash 4.0
behaves because I would prefer to know that negative values are
illegal than to have them silently co-erced to the corresponding
unsigned integers . The bash 3.0 behaviour played havoc with a binary
search algorithm that I wrote until I realised that -1 had been
coerced to 255.

jon.




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