From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 224772DC76F for ; Tue, 10 Feb 2026 23:38:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770766691; cv=none; b=WdpYLZJsFKe4yHfLsXmlZmLBRyMfK3QQqOidXXLjqGsdBpxj90IqyRGC2a9lathmzSTDtKaTQcqVBts0v6Ipv93ceu8Dew+G8UM4bLDice7EuNnD/X+rC3VbgroopG56H70KIw/8UqCTWXr07KHSv1JG1ahW58r2Uz3BNcMZASc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770766691; c=relaxed/simple; bh=ne8tQwSIpk1ThpFg8zj24docJEqb7kOQ2Lq+64CsQGI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VUEVBdv8XW4fXeka/RIwFcRCYF+Gqzc3J9EtfyVqn2/j8rik1/i2brbLEl9+WOHYrhckV6DiOzekI579zUCzTYWqvVxs/MGG7hXQyvs8kZeG2sbNptieWwpIlB2SpjGmCgiZE//AMM8I0LaRsZovDafsiK8X09DjZRZa2dkbCTo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RzaHpkjs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RzaHpkjs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B802FC116C6; Tue, 10 Feb 2026 23:38:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770766690; bh=ne8tQwSIpk1ThpFg8zj24docJEqb7kOQ2Lq+64CsQGI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RzaHpkjsLVHfyv5xOJM7mF7OEeWpN6AjuICGhiSfvEgG+oa1PzRYMYYbyG/cUqhI6 xdhdkU9WAY0d/zhSr4sjv7Ds83oZzVgwmqpUxxoxIyigZxoxhNIhfjW3lelqmHjYFF w7MLfLhrEUuBMbfTq4TnJAAiq5HPsuqk1uUT2GVrF4cvIrvThpYbI7o/DmVDTXeJ2Y OFKl/PJNmgfsQ8CGh70Q0dV5vdm3IGqPjBeo7OKOI8oknWMqAaH+ygUX7EyfUkQaGj jY2LeknxkUaWyFJBK8d+4939PoM5DjaZqsvZfc87n5+pvgWlKGu4b+T+C4OWHJ6Bmq XMEcsisuP8fWA== Date: Wed, 11 Feb 2026 00:38:07 +0100 From: Alejandro Colomar To: Morten Welinder Cc: Joseph Myers , linux-man@vger.kernel.org, libc-help@sourceware.org Subject: Re: floor/ceil man pages Message-ID: References: Precedence: bulk X-Mailing-List: linux-man@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="yr2smezzdcctorfd" Content-Disposition: inline In-Reply-To: --yr2smezzdcctorfd Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable From: Alejandro Colomar To: Morten Welinder Cc: Joseph Myers , linux-man@vger.kernel.org, libc-help@sourceware.org Subject: Re: floor/ceil man pages Message-ID: References: MIME-Version: 1.0 In-Reply-To: Hi Morten, Joseph, On 2026-01-29T13:08:43-0500, Morten Welinder wrote: > For NaN, it comes down to the ieee spec. Ieee-754-2008 in Section 6.3 > specifies that the only operations delivering a defined sign for NaNs > are: copy, abs, negate, and copysign. "For all other operations, this > standard does not specify the sign bit of a NaN result, even when > there is only one input NaN, or when the NaN is produced from an > invalid operation." >=20 > The glibc people have in the past defended the freedom to return > whatever sign on NaN they feel like. See > https://sourceware.org/bugzilla/show_bug.cgi?id=3D31104 for an example > where float/double/long double versions of various functions disagree > on what sign to return for NaN. >=20 > I don't think the man page should promise more than some standard > requires unless the implementation is specifically offering further > guarantees. Agree. Would you want to send a patch? Have a lovely night! Alex >=20 > M. --=20 --yr2smezzdcctorfd Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEES7Jt9u9GbmlWADAi64mZXMKQwqkFAmmLwV8ACgkQ64mZXMKQ wqmVSQ/9Ejs+DvLRZavijfDdr0Zh6t8q6yUT2FgKmOiJCNTWeKHDQPEEphFPfONm YoG0LrM3xQcDqEnEcmQNoMSZC+h9WcBzJSkdc5uRGJhpI40UsPs1+a7GLSaFhyFr +hK1WkYXxkN+PSM87G9F3/cq9qjvqyQxrMGovksqg0iDbvUFX241KBKkn6SFEhW7 y72a2gp3Pwu3USoCCowvzOQVVYSwkHlFpFbIvQ4bQUQxkPOiBY3GxghBfOtmE/Sv LX35DXOvkbCp1ph+jCNShywsNeCPSo94okn7AFAVZlRyKplP6asUGWDZcHjenA0A HSZbGC0UP7PCg+7sDnVCjXHDH4N4KaHvIeEe42eu/5DMPWxHMws356Cg6LjfrYDh oawrbbYuWWo6pEZxpGptwTo6mqwt6bAxOvjGp8nkr793R5JjK8xsce8MPOYvZICU LNOnlfODHY+rMKCqZTn9VWCqe8olb08QAMj7bcc+4Gz9wUUU7ZKmd58gXu2LRLMP cQj+CLKLHKVZi9QoyUauNjBD9JajHVGGC7OzkMpjUNjzUH1eSM9s7ZCwUQo8Hw2y WgtZBFtc+OWOGKKsY3AuTErfa260VeWCfh9n0AuQjd9ESo53gPNJvgfiO55d0cR9 Y6fPunShY+zvRAfnImhfcWPGVbK8un9cBvBoFrkX3rdUiBmKsPA= =GHLy -----END PGP SIGNATURE----- --yr2smezzdcctorfd--