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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BF844D1038C for ; Wed, 26 Nov 2025 08:22:17 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vOAmZ-00035x-De; Wed, 26 Nov 2025 03:21:47 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vOAmX-0002zC-Qy for qemu-devel@nongnu.org; Wed, 26 Nov 2025 03:21:45 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vOAmV-0005GI-Pa for qemu-devel@nongnu.org; Wed, 26 Nov 2025 03:21:45 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1764145302; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=H+VA6Pg1eEjV5FHvHC64VYelZeiqkfschI+tgUuYGM4=; b=gZNL8kGaa5APuUGkhlv9G4SLn66UWiEf1aIVomwuTCRTpJBZUqKzQtkhPhB5lza0JLxtBP JIchKx6MfMtNorAOOXNj6lqAUubEv4L0Whp46tJA506ZobznBTElU43Nw5D0m9Ev3wDC9d R7U+7ydWktKVKcTS7V+uiPt6e4MLPQM= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-516-cbcF74HwP4WApDfm3z2nSA-1; Wed, 26 Nov 2025 03:21:41 -0500 X-MC-Unique: cbcF74HwP4WApDfm3z2nSA-1 X-Mimecast-MFC-AGG-ID: cbcF74HwP4WApDfm3z2nSA_1764145300 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-42b2c8fb84fso3395059f8f.2 for ; Wed, 26 Nov 2025 00:21:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1764145300; x=1764750100; darn=nongnu.org; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:cc:to:subject:user-agent:mime-version:date :message-id:from:to:cc:subject:date:message-id:reply-to; bh=H+VA6Pg1eEjV5FHvHC64VYelZeiqkfschI+tgUuYGM4=; b=BCJNskefpLk7dhB0p9eTnNL+hl3/9F9r0UcqIAFS/edvBHiAPUuenRkIWZZCkKE6TK Ag9DOoRxFmHE8ESPYhqbGq2nTwGdOH7YDKWiQENw78ua9M0qBAhVr9qla4k2sGofxXAK hCjYeYAVykyPlxqo+z1ygYxy6y0Pa/NEWy+9zvqBXTDvz0uGVwXp6NIyfjvWYv92maU5 ZvNhvhhO45ZxzsdFDmaCSeqzeuaHo6X6uUWJuSKXPkeo69G0kk2X4+NlYEDFDUVFUmkO nXy2vvO5dFaICTJul5ZUxHYDDEH/whcyiwHPAwHQFIE04VYIy9ZX/y+DUN+rm1+iolhk WLEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764145300; x=1764750100; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:cc:to:subject:user-agent:mime-version:date :message-id:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=H+VA6Pg1eEjV5FHvHC64VYelZeiqkfschI+tgUuYGM4=; b=sKj3P0DNzHehnEchvtRLydwGgzkc5ah8c4WdyzIqvANVQCIWdxqvQ/u5jXGhYHW0dJ J5oX+cEXlek7o1jRqVE83q60Ti6w8GQqdpBIdu2lF4CZErs5xvpmjGglwgbzgrpRYfXy 60UtGVuXdWCMY+YtydB3fMeH8NQ6M+nl/lPXK8S/mKQarqN2dT1taH42UIl1aX+nQl4q xCx2U+sLy49GI06NHEAaI4N3ebI0igudXuk2/UNZ6LdENZCjpCimHbwpJg3QTEQKElhm SCSZ4LE16vb66gANX6zisHTFi96qqdXM7X8XWhFbHXrhVhv6i6LC6e3QYSyAiH6avNaJ Ww4g== X-Forwarded-Encrypted: i=1; AJvYcCWl0h2vXxa/qf7HKHkx8S08+CqZd0DoUj8qeNaGn9Q/JdNHq+uiehmgO2f3YXONSrxpmY1qtUcGLuEG@nongnu.org X-Gm-Message-State: AOJu0YxqWoiJlMYzwguGuvAPZTXE0EaeWnU3DihyEQQT6k68K7VtVQ4z qZ5zN/xutd7PTqDDHojcINj2iXOEIq0zXcPJwWNTiwTnTgRHJxKzLZhrGEu2RYHrgrfikbzmNP1 FipqUs/gcG1IgBuPej5jiwS+dgZ86pYDkXv/989bfY6qhbBKFHcd5LZhM X-Gm-Gg: ASbGncvuR7SpGy8RYA7YIHQOPBPwTmB38H7bTktzBW/PtlLaBelLoImeDmeiEmsF139 7wkkxnDlotVtzp5zKk7tYOUUjkG5SJ+lHEKh9CW3JByEVRP6UFNlJe4P9Mj+FSUtBSeKYQnLCso vYEbjN3XypgbZrREK6BgKGIXfAZv7L2GraBTRZEPjkwOKODsDDfhLvQ8Kx5KQ4S3/upImQ5fhkU mPhUYljiB1Qdxkrcd7OuzHH2NQdZp92s4m1huoqDrf2E4f58fDMF4GpfsrDaKGbC0Ss6qzx5N9m sYiTbRc3iz0OWhsLpk4LX/Pt+RAXNDzCWkrkuEmyADUUoluxY4ZChJAUKFrGYMzEmBkML0oIfzz OKhIjUa+bwMXMCn0xZ5wrnsL+u8W/aamZEc130sSsEv1KNCwP X-Received: by 2002:a05:6000:2f85:b0:42b:4247:b077 with SMTP id ffacd0b85a97d-42e0f34fa15mr5961070f8f.41.1764145299635; Wed, 26 Nov 2025 00:21:39 -0800 (PST) X-Google-Smtp-Source: AGHT+IE1Yz0QCUwDsEhB8h2mzBZ7LDhY3jJAmL3rMCF6nqYdT4RsvdEMZAl+KPCaL21fLEeT4Y6g/g== X-Received: by 2002:a05:6000:2f85:b0:42b:4247:b077 with SMTP id ffacd0b85a97d-42e0f34fa15mr5961038f8f.41.1764145299240; Wed, 26 Nov 2025 00:21:39 -0800 (PST) Received: from ?IPV6:2a01:e0a:280:24f0:576b:abc6:6396:ed4a? ([2a01:e0a:280:24f0:576b:abc6:6396:ed4a]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-42cb7f363c0sm39808837f8f.18.2025.11.26.00.21.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 26 Nov 2025 00:21:38 -0800 (PST) Message-ID: Date: Wed, 26 Nov 2025 09:21:38 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Should functions that free memory clear the pointer? To: Markus Armbruster , Peter Xu Cc: =?UTF-8?Q?Marc-Andr=C3=A9_Lureau?= , qemu-devel@nongnu.org, farosas@suse.de, peter.maydell@linaro.org References: <20251125070554.2256181-1-armbru@redhat.com> <875xayxo6t.fsf@pond.sub.org> <87ikeygd83.fsf@pond.sub.org> <87wm3dfhk9.fsf_-_@pond.sub.org> From: =?UTF-8?Q?C=C3=A9dric_Le_Goater?= Content-Language: en-US, fr Autocrypt: addr=clg@redhat.com; keydata= xsFNBFu8o3UBEADP+oJVJaWm5vzZa/iLgpBAuzxSmNYhURZH+guITvSySk30YWfLYGBWQgeo 8NzNXBY3cH7JX3/a0jzmhDc0U61qFxVgrPqs1PQOjp7yRSFuDAnjtRqNvWkvlnRWLFq4+U5t yzYe4SFMjFb6Oc0xkQmaK2flmiJNnnxPttYwKBPd98WfXMmjwAv7QfwW+OL3VlTPADgzkcqj 53bfZ4VblAQrq6Ctbtu7JuUGAxSIL3XqeQlAwwLTfFGrmpY7MroE7n9Rl+hy/kuIrb/TO8n0 ZxYXvvhT7OmRKvbYuc5Jze6o7op/bJHlufY+AquYQ4dPxjPPVUT/DLiUYJ3oVBWFYNbzfOrV RxEwNuRbycttMiZWxgflsQoHF06q/2l4ttS3zsV4TDZudMq0TbCH/uJFPFsbHUN91qwwaN/+ gy1j7o6aWMz+Ib3O9dK2M/j/O/Ube95mdCqN4N/uSnDlca3YDEWrV9jO1mUS/ndOkjxa34ia 70FjwiSQAsyIwqbRO3CGmiOJqDa9qNvd2TJgAaS2WCw/TlBALjVQ7AyoPEoBPj31K74Wc4GS Rm+FSch32ei61yFu6ACdZ12i5Edt+To+hkElzjt6db/UgRUeKfzlMB7PodK7o8NBD8outJGS tsL2GRX24QvvBuusJdMiLGpNz3uqyqwzC5w0Fd34E6G94806fwARAQABzSJDw6lkcmljIExl IEdvYXRlciA8Y2xnQHJlZGhhdC5jb20+wsGRBBMBCAA7FiEEoPZlSPBIlev+awtgUaNDx8/7 7KEFAmTLlVECGwMFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AACgkQUaNDx8/77KG0eg// S0zIzTcxkrwJ/9XgdcvVTnXLVF9V4/tZPfB7sCp8rpDCEseU6O0TkOVFoGWM39sEMiQBSvyY lHrP7p7E/JYQNNLh441MfaX8RJ5Ul3btluLapm8oHp/vbHKV2IhLcpNCfAqaQKdfk8yazYhh EdxTBlzxPcu+78uE5fF4wusmtutK0JG0sAgq0mHFZX7qKG6LIbdLdaQalZ8CCFMKUhLptW71 xe+aNrn7hScBoOj2kTDRgf9CE7svmjGToJzUxgeh9mIkxAxTu7XU+8lmL28j2L5uNuDOq9vl hM30OT+pfHmyPLtLK8+GXfFDxjea5hZLF+2yolE/ATQFt9AmOmXC+YayrcO2ZvdnKExZS1o8 VUKpZgRnkwMUUReaF/mTauRQGLuS4lDcI4DrARPyLGNbvYlpmJWnGRWCDguQ/LBPpbG7djoy k3NlvoeA757c4DgCzggViqLm0Bae320qEc6z9o0X0ePqSU2f7vcuWN49Uhox5kM5L86DzjEQ RHXndoJkeL8LmHx8DM+kx4aZt0zVfCHwmKTkSTQoAQakLpLte7tWXIio9ZKhUGPv/eHxXEoS 0rOOAZ6np1U/xNR82QbF9qr9TrTVI3GtVe7Vxmff+qoSAxJiZQCo5kt0YlWwti2fFI4xvkOi V7lyhOA3+/3oRKpZYQ86Frlo61HU3r6d9wzOwU0EW7yjdQEQALyDNNMw/08/fsyWEWjfqVhW pOOrX2h+z4q0lOHkjxi/FRIRLfXeZjFfNQNLSoL8j1y2rQOs1j1g+NV3K5hrZYYcMs0xhmrZ KXAHjjDx7FW3sG3jcGjFW5Xk4olTrZwFsZVUcP8XZlArLmkAX3UyrrXEWPSBJCXxDIW1hzwp bV/nVbo/K9XBptT/wPd+RPiOTIIRptjypGY+S23HYBDND3mtfTz/uY0Jytaio9GETj+fFis6 TxFjjbZNUxKpwftu/4RimZ7qL+uM1rG1lLWc9SPtFxRQ8uLvLOUFB1AqHixBcx7LIXSKZEFU CSLB2AE4wXQkJbApye48qnZ09zc929df5gU6hjgqV9Gk1rIfHxvTsYltA1jWalySEScmr0iS YBZjw8Nbd7SxeomAxzBv2l1Fk8fPzR7M616dtb3Z3HLjyvwAwxtfGD7VnvINPbzyibbe9c6g LxYCr23c2Ry0UfFXh6UKD83d5ybqnXrEJ5n/t1+TLGCYGzF2erVYGkQrReJe8Mld3iGVldB7 JhuAU1+d88NS3aBpNF6TbGXqlXGF6Yua6n1cOY2Yb4lO/mDKgjXd3aviqlwVlodC8AwI0Sdu jWryzL5/AGEU2sIDQCHuv1QgzmKwhE58d475KdVX/3Vt5I9kTXpvEpfW18TjlFkdHGESM/Jx IqVsqvhAJkalABEBAAHCwV8EGAECAAkFAlu8o3UCGwwACgkQUaNDx8/77KEhwg//WqVopd5k 8hQb9VVdk6RQOCTfo6wHhEqgjbXQGlaxKHoXywEQBi8eULbeMQf5l4+tHJWBxswQ93IHBQjK yKyNr4FXseUI5O20XVNYDJZUrhA4yn0e/Af0IX25d94HXQ5sMTWr1qlSK6Zu79lbH3R57w9j hQm9emQEp785ui3A5U2Lqp6nWYWXz0eUZ0Tad2zC71Gg9VazU9MXyWn749s0nXbVLcLS0yop s302Gf3ZmtgfXTX/W+M25hiVRRKCH88yr6it+OMJBUndQVAA/fE9hYom6t/zqA248j0QAV/p LHH3hSirE1mv+7jpQnhMvatrwUpeXrOiEw1nHzWCqOJUZ4SY+HmGFW0YirWV2mYKoaGO2YBU wYF7O9TI3GEEgRMBIRT98fHa0NPwtlTktVISl73LpgVscdW8yg9Gc82oe8FzU1uHjU8b10lU XOMHpqDDEV9//r4ZhkKZ9C4O+YZcTFu+mvAY3GlqivBNkmYsHYSlFsbxc37E1HpTEaSWsGfA HQoPn9qrDJgsgcbBVc1gkUT6hnxShKPp4PlsZVMNjvPAnr5TEBgHkk54HQRhhwcYv1T2QumQ izDiU6iOrUzBThaMhZO3i927SG2DwWDVzZltKrCMD1aMPvb3NU8FOYRhNmIFR3fcalYr+9gD uVKe8BVz4atMOoktmt0GWTOC8P4= In-Reply-To: <87wm3dfhk9.fsf_-_@pond.sub.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=clg@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.152, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 11/26/25 07:12, Markus Armbruster wrote: > Peter Xu writes: > >> On Tue, Nov 25, 2025 at 07:48:44PM +0100, Markus Armbruster wrote: >>> My main argument remains this one: our deallocating functions don't work >>> that way. For better or worse. >>> >>> I don't want the Error API free differently. >> >> Yes, it's fair. >> >> IMHO, it's a matter of taste, > > Depends on context. > > Modula-2's DISPOSE takes the pointer by reference and clears it. C's > free() takes it by value. Matter of taste when these were designed. > > But when one style has become overwhelmingly prevalent, it's no longer a > matter of taste. This is arguably the case in C. > >> and maybe that's also why I liked >> g_clear_pointer() but not everyone likes it.. said that, when we have >> g_clear_pointer() it also makes the current form more flexible, because we >> can apply g_clear_pointer() on top when we need a reset.. > > I'm no friend of g_clear_pointer(). I find > > g_clear_pointer(&ptr, free_frob); > > a rather roundabout way to say > > free_frob(ptr); > ptr = NULL; > > Any C programmer will immediately understand the latter. For the > former, you need to know one more little thing. Yes, we can all get > used to these little things, but it's one more little thing new people > have to learn and internalize. Even little things add up. > > If an entire project gets into the habit of using it religiously, it may > reduce "forgot to zap the reference" bugs some. Until then, it feels > like a net negative to me. I'm not a big fan of g_clear_pointer() either; I prefer being explicit, even if it means a bit of redundancy. Thanks, C. > >> I'll follow your advise on error reporting for migration. > > Thank you! > >