From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C779EB64DD for ; Mon, 7 Aug 2023 08:16:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229921AbjHGIQP convert rfc822-to-8bit (ORCPT ); Mon, 7 Aug 2023 04:16:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229776AbjHGIQO (ORCPT ); Mon, 7 Aug 2023 04:16:14 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F9FE1BB for ; Mon, 7 Aug 2023 01:16:12 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-201-6FPU6Xj6Ow-DPKP--BfwjA-1; Mon, 07 Aug 2023 09:16:06 +0100 X-MC-Unique: 6FPU6Xj6Ow-DPKP--BfwjA-1 Received: from AcuMS.Aculab.com (10.202.163.6) by AcuMS.aculab.com (10.202.163.6) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Mon, 7 Aug 2023 09:16:02 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Mon, 7 Aug 2023 09:16:02 +0100 From: David Laight To: 'Zhangjin Wu' , "w@1wt.eu" CC: "arnd@arndb.de" , "linux-kernel@vger.kernel.org" , "linux-kselftest@vger.kernel.org" , "thomas@t-8ch.de" Subject: RE: [PATCH v6 06/15] tools/nolibc: __sysret: support syscalls who return a pointer Thread-Topic: [PATCH v6 06/15] tools/nolibc: __sysret: support syscalls who return a pointer Thread-Index: AQHZyGJM8MfmHZ1C3ES1BFx0kL6bna/eeWXw Date: Mon, 7 Aug 2023 08:16:02 +0000 Message-ID: References: <20230806095846.GB10627@1wt.eu> <20230806123351.35202-1-falcon@tinylab.org> In-Reply-To: <20230806123351.35202-1-falcon@tinylab.org> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org From: Zhangjin Wu > Sent: 06 August 2023 13:34 ... > Based on your macro version, I tried to use the is_signed_type() from kernel, > it seems works. You'll find that (void *)0 isn't 'constant enough' for is_constexpr() - so is_constexpr((type)0) can be used to detect pointer types. Probably requires an 'is_pointer_type()' define. This also rather means that is_signed_type() needs to be wrapped in is_constexpr() - probably generating header file inclusion hell. I'm going to add a comment on v3 of the patch... David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)