Re: [bug #37737] Contained subexpressions don't follow POSIX

[Eric Blake]

On 11/14/2012 03:29 PM, Роман Донченко wrote:
> Eric Blake <address@hidden> писал в своём письме Thu, 15 Nov 2012
> 02:11:57 +0400:
> 
>> For reference, on Cygwin (where m4 uses gnulib's regex engine, rather
>> than glibc's) I get correct behavior:
>>
>> $ printf %s 'regexp(abab, \(a\(b\)*\)*\2, \&-\1-\2)' | m4
>> -1
> 
> That's interesting, because I don't:
> 
> $ uname -sr
> CYGWIN_NT-6.1-WOW64 1.7.17(0.262/5/3)
> 
> $ m4 --version
> m4 (GNU M4) 1.4.16
> Packaged by Cygwin (1.4.16-1)
> (etc, etc)
> 
> $ printf %s 'regexp(abab, \(a\(b\)*\)*\2, \&-\1-\2)' | m4
> abab-a-b
> 
> In fact, Cygwin was where I did the test in the OP (although I've
> previously observed the bug on Linux, too).

Arg, chalk that up to a typo on my part: when I was retyping the command
line between the systems, I omitted a comma.  The correct result would
be the empty string, not -1; and I confirm that cygwin has the same
behavior as Linux (probably due to gnulib copying from glibc).

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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