X-Recipient: archive-cygwin AT delorie DOT com
DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:subject:to:references:from:message-id:date
	:mime-version:in-reply-to:content-type; q=dns; s=default; b=IMi/
	OWxB6u1VzG3rtZgX6DKTapcChdHNjACQLPYLLmkv4kzO8C9d3cgCizYRwLOmEcoD
	ve8HpsyW0LkxTlHFhjF/rQG9u721bdflk3uu6a6tTGR/ffzGWyQuWLLe5NXSF480
	MuIthpG13AfkUWZGveUT8KXUJkeAvC37/6naptc=
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:subject:to:references:from:message-id:date
	:mime-version:in-reply-to:content-type; s=default; bh=F6gAYz316x
	SgQDzxGJNb+WXUyaM=; b=LAE5t/6XGlcDpzQtnt2sknvsq+uxvNBV/Lj42s/MW5
	/Tjag8AqGQzlKlK5hBu7ChmI3hnVc908HeHGuoMi7QJzc51fY96oG7IkGauFP5se
	WwRwqiNIXSgBGDYBPa7SP/ZfwaeeXNX8GylYrA8ypucKs+8C7++Uf7M7XJudKnBp
	c=
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id: <cygwin.cygwin.com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
Authentication-Results: sourceware.org; auth=none
X-Spam-SWARE-Status: No, score=-0.9 required=5.0 tests=BAYES_00,KAM_LAZY_DOMAIN_SECURITY,SPF_HELO_PASS autolearn=no version=3.3.2 spammy=expanding, Principal
X-HELO: mx1.redhat.com
Subject: Re: manpage searches "^\s+keyword\s" vs. ???
To: cygwin AT cygwin DOT com
References: <5C4E5F0F DOT 2090403 AT tlinx DOT org> <1210066491 DOT 20190130214043 AT yandex DOT ru>
From: Eric Blake <eblake AT redhat DOT com>
Openpgp: preference=signencrypt
Message-ID: <c8f36794-db4a-8148-0547-eaad351c7795@redhat.com>
Date: Wed, 30 Jan 2019 13:09:21 -0600
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0
MIME-Version: 1.0
In-Reply-To: <1210066491.20190130214043@yandex.ru>
Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Dv2TJVVB2yxAC0lbXsef0NjfjzitZYa4K"
X-IsSubscribed: yes

--Dv2TJVVB2yxAC0lbXsef0NjfjzitZYa4K
Content-Type: multipart/mixed; boundary="16zvbKxp63xDMFHiZU0ucpzpnwx66nX10";
 protected-headers="v1"
From: Eric Blake <eblake AT redhat DOT com>
To: cygwin AT cygwin DOT com
Message-ID: <c8f36794-db4a-8148-0547-eaad351c7795 AT redhat DOT com>
Subject: Re: manpage searches "^\s+keyword\s" vs. ???
References: <5C4E5F0F DOT 2090403 AT tlinx DOT org> <1210066491 DOT 20190130214043 AT yandex DOT ru>
In-Reply-To: <1210066491 DOT 20190130214043 AT yandex DOT ru>


--16zvbKxp63xDMFHiZU0ucpzpnwx66nX10
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: quoted-printable

On 1/30/19 12:40 PM, Andrey Repin wrote:

>=20
> I've been puzzled by this since=E2=80=A6 forever, it seems.
> This is something in less, but all the `man less` says is "regular expres=
sion
> library provided by your system".

\s is a non-standard regex extension - glibc provides it, Cygwin has not
(at least, historically).  POSIX provides [[:space:]] as a portable
alternative (although not all libc have implemented all of POSIX yet),
but is annoyingly long to type.

Similarly, BSD regex (which is where Cygwin derives its regex from)
supports the non-standard regex extension [[:<:]] as a word boundary,
while glibc has the same feature but spelled \<.  I also seem to recall
a patch in the past to teach Cygwin to respect \< by expanding it to
[[:<:]] before calling into the BSD-derived code (although I couldn't
actually find one in a quick search); a similar patch to expand \s into
[[:space:]] would be a reasonable idea.

> I guess this is down to compilation options at this point.

Not so much compilation options of man and less, but rather the code
used in Cygwin itself for handling regex.

--=20
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


--16zvbKxp63xDMFHiZU0ucpzpnwx66nX10--

--Dv2TJVVB2yxAC0lbXsef0NjfjzitZYa4K
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: OpenPGP digital signature
Content-Disposition: attachment; filename="signature.asc"

-----BEGIN PGP SIGNATURE-----

iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAlxR9mEACgkQp6FrSiUn
Q2pjJwf9Ghae+VFlz5fRVG3nK2TF/cUp/JMF1L1HUlfEonVatBasodh8nFRZ/QxF
kfJ8ek6b3nGcuLeVdhPI+vty5c7ijy9+960kPFOp4myWplnXHsCA5XHo8lNk5iuw
e9rOMEj6fQL9kRqacWRerVuCO5aO3N7TFXWM/ifTrh9DUumWENfZttyjv/TQM1+7
slFzbt94Wk/TYau6SpA42yDxiYlucMKBCcrQwOdj4G4tYtJgkiX8LvXi0IJzI+RJ
63Z33uRGlEYFm5DlDAm3skVNS0wuDKtYvdA7Aus5asi/pOcLBwLEZTKweZ+ydSRd
y+crr51j2eWYTw2U0NXnBmQp1iuuHw==
=S7++
-----END PGP SIGNATURE-----

--Dv2TJVVB2yxAC0lbXsef0NjfjzitZYa4K--