From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 601CD3321A1 for ; Mon, 15 Jun 2026 21:06:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781557609; cv=none; b=Ts38gq4M8UNOtgMyMzR/unERTZdjbqOukAkr0sFaUg5yJyj6rOPC9pdU0TW6414AFcbcN/6Xul5xxpSmC+2gZEiy3XuDwNa5+VhkAeFYUhKgBXKW1dWvpqPF5IuE30Cdm1USnzzeaJreErS2XYUKF48zLa+4u+kGt4Fe5ha24Jo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781557609; c=relaxed/simple; bh=1CDOZHva8L/5eUg6BmOoxwpQSB+uAnFlwUdPvKoCA9A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=FRw2geo8BApiEsG3TqaIquvoBzOEwEZRjgDVVyO34qSitwyhHOC3y7imglvHjX3zUNW0wORIGzwz9O/9xRFq4wO+xqXwYFkqObsWRX8qEG1XhmwsI3lUPuot0JUmUXz9AqgKRdVcdCJa11hLAKiDjaVqfHVTiBS0gSa11o6sicQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OgRv7law; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OgRv7law" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 048361F000E9; Mon, 15 Jun 2026 21:06:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781557608; bh=ef2pKlU2Bwk8Do/QQWBtgJkbrq4supmztdBfFaaAUFU=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=OgRv7lawTsP5KddM+aiIZ0/fG1lamK5W4fU6KbcmcGCmg74pwqOPYlnABF0/4hGYN bjGqhhNezN1ZOfwzBPYfutPBpOzovNRKgU/DH6RAKRcFTpBNK5vIc2ArsOGf6veV33 TinAGLe8iC4Q1SQ/NcaqmNcbSw0qweEIvCOG0lcHqAp8emj2pj0Yy7v+p4V7XpgkUH CARrMo8lwhFJ65SAi2p051GhuQeQ6mjAK7vABlvpUWnEWSSurN5Aj91ZXb2LmnXBou ro/A51zUpMFwOq42G/bdygFkl/EDnDOEAN6ENMVdJ2JJsBE5rZcCnOVH8K7vH5661G 2boSgIteAgfBQ== Date: Mon, 15 Jun 2026 23:06:44 +0200 From: Alejandro Colomar To: Joseph Myers Cc: libc-alpha@sourceware.org, gcc@gcc.gnu.org, linux-man@vger.kernel.org Subject: Re: _ISOCxx_SOURCE 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="434t6xcoxsssvxwe" Content-Disposition: inline In-Reply-To: --434t6xcoxsssvxwe Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable From: Alejandro Colomar To: Joseph Myers Cc: libc-alpha@sourceware.org, gcc@gcc.gnu.org, linux-man@vger.kernel.org Subject: Re: _ISOCxx_SOURCE Message-ID: References: MIME-Version: 1.0 In-Reply-To: Hi Joseph, On 2026-06-15T17:20:17+0000, Joseph Myers wrote: > On Sat, 13 Jun 2026, Alejandro Colomar via Gcc wrote: >=20 > > I was reviewing the feature_test_macros(7) page, and found the > > documentation of the _ISOC{99,11,23,...}_SOURCE macros to be incorrect. > > And thinking about fixing that led me to think that the design of those > > macros is less than ideal. >=20 > Users should normally use -std=3D options with the compiler to get matchi= ng=20 > language and library features. These feature test macros are mainly for= =20 > niche cases with old compilers. So I don't think any new user-facing=20 > design for them should be added (the C23 and later ones already use the= =20 > newer __GLIBC_USE style of conditionals in the header implementation). Makes sense. Should I document that users should avoid setting them directly (and that they should use the corresponding compiler flag)? Have a lovely night! Alex --=20 --434t6xcoxsssvxwe Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEES7Jt9u9GbmlWADAi64mZXMKQwqkFAmowaV0ACgkQ64mZXMKQ wqn1Hw/+Ia9QB5ReK1aGVi8AZD10RqVsik9G5M2RX/lX/rsBh2I2O+qPjTT9MAKA uJESJeWKGS1+CLZIRCuWUgmwf/IfFsaAJxDvB8u8A3yPcn1ra1GcZyu+f2NHu3S9 rGZOdwc+h6/uRgK2KsVl52AtKISbD7uAxOIdx5ECLQAkBFGaGsSdQj/CbrEOfYjm 9Y5NsOCmCKyjFy4PZKXyQvsVC42LL8GzW3MI5NvpQhQUXzDdrHmmRtAHhCOiU7oS FaALVFlY3Iki3FrIclbHepN4VmslbLh0kW2tKYDIM/bcwrjGzF23V+HM7cGln2v5 I/4nBgMysG1qsIvcSDsgNqJ72tz/X2UEJZSdBjhyhBN37mn/36yi+KVI54eLH8RY mH8vQQNhtX0jEkGwv/r9xnAGmzgdBar7sX4nFIZduH9riWQypOBb0fTVsa8jb8RV Y+nIChuDKxzLwjYsOS/IJJD3GU2SjTqU3eexXPGNL8qhYzpHTZv2VT9nD+/YUi0/ KdZGwCaGIgo1/qU1hkXTl8O57r0fQJyzPvtZBrXX2b9dOIx1clzRDcqMgM5+M8aR OWs8AWS8uxkIPM3vWrjKdbg9Eu3/uDu9QnGgZKF9PqNlTpX+ONIGIaIMvU09skFA PkQrhag0ndSnSNi0yjTGFhvJNoyvjN7cYDhHWRiekxSblmbAUTs= =ERG9 -----END PGP SIGNATURE----- --434t6xcoxsssvxwe--