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[216.205.24.124]) by mx.google.com with ESMTPS id n4si5153075edd.117.2021.09.03.04.57.12 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 03 Sep 2021 04:57:13 -0700 (PDT) Received-SPF: pass (google.com: domain of berrange@redhat.com designates 216.205.24.124 as permitted sender) client-ip=216.205.24.124; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b="cYHl/+9s"; spf=pass (google.com: domain of berrange@redhat.com designates 216.205.24.124 as permitted sender) smtp.mailfrom=berrange@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1630670232; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=qx7q+ynwNlUdf5xhudsXgJ7h+396EMUM6+GIc2Uds/E=; b=cYHl/+9sn0ubfntAel4ahtyV7xyc65fFH1yEOoPYgv3V7uYdO81YPrEdKsrdeVOKPYXiZx jOvoGI2SgLscCllC9nvTzELbxN7xqXxRyPhSgMIjsPEG/ACR8yDJ83r66pGq9iSe6gT+d8 TqIJfahtInq8f/vuR6+QyybkxL7zjg4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-433-FBl6eYJ5Nui1zOv_iC-6fw-1; Fri, 03 Sep 2021 07:56:54 -0400 X-MC-Unique: FBl6eYJ5Nui1zOv_iC-6fw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6370684A5E0; Fri, 3 Sep 2021 11:56:51 +0000 (UTC) Received: from redhat.com (unknown [10.39.193.241]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F080E5D9F0; Fri, 3 Sep 2021 11:56:24 +0000 (UTC) Date: Fri, 3 Sep 2021 12:56:22 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Vladimir Sementsov-Ogievskiy Cc: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , qemu-devel@nongnu.org, Fam Zheng , Peter Maydell , Li Zhijian , "Michael S. Tsirkin" , Jason Wang , Christian Schoenebeck , Yuval Shaia , Peter Xu , Gerd Hoffmann , Alexandre Iooss , Eric Blake , qemu-block@nongnu.org, Zhang Chen , Alex =?utf-8?Q?Benn=C3=A9e?= , Helge Deller , David Hildenbrand , Markus Armbruster , "Gonglei (Arei)" , Stefan Weil , Laurent Vivier , Thomas Huth , Eduardo Habkost , Michael Roth , Richard Henderson , Greg Kurz , Alex Williamson , qemu-arm@nongnu.org, Paolo Bonzini , John Snow , David Gibson , Kevin Wolf , Laurent Vivier , Shannon Zhao , Hanna Reitz , qemu-ppc@nongnu.org, Igor Mammedov , Mahmoud Mandour Subject: Re: [PATCH 02/28] glib-compat: Introduce g_memdup2() wrapper Message-ID: Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: <20210903110702.588291-1-philmd@redhat.com> <20210903110702.588291-3-philmd@redhat.com> <04ba0442-08ca-bf88-3f04-0be00c11bd1b@virtuozzo.com> MIME-Version: 1.0 In-Reply-To: <04ba0442-08ca-bf88-3f04-0be00c11bd1b@virtuozzo.com> User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-TUID: rSJb7zZ7x1pw On Fri, Sep 03, 2021 at 02:51:21PM +0300, Vladimir Sementsov-Ogievskiy wrote: > That was most probably already discussed, so sorry my question: > > Why we can't just do > > #if ! GLIB_CHECK_VERSION(2, 68, 0) > static inline gpointer g_memdup2(gconstpointer mem, gsize byte_size) > { > gpointer new_mem; > > if (mem && byte_size != 0) { > new_mem = g_malloc(byte_size); > memcpy(new_mem, mem, byte_size); > } else { > new_mem = NULL; > } > > return new_mem; > } > #endif > > ? This doesn't play with GLIB_VERSION_MAX_ALLOWED - any use of g_memdup2 will trigger compile warnings since we're using an API that only exists in a glib version newer than our declared baseline. The inline wrapper + macro is a trick that lets us backport new features, while avoiding the compile warnings. This is documented in the include/glib-compat.h file that Philippe is modifying. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| 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 X-Spam-Level: X-Spam-Status: No, score=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73C88C433EF for ; Fri, 3 Sep 2021 12:04:35 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 37922610A1 for ; Fri, 3 Sep 2021 12:04:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 37922610A1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:56114 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mM7vu-0005ev-CP for qemu-devel@archiver.kernel.org; Fri, 03 Sep 2021 08:04:34 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54836) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mM7ol-0000dt-3Y for qemu-devel@nongnu.org; Fri, 03 Sep 2021 07:57:11 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:35480) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mM7oi-0001yK-Hv for qemu-devel@nongnu.org; Fri, 03 Sep 2021 07:57:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1630670227; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=qx7q+ynwNlUdf5xhudsXgJ7h+396EMUM6+GIc2Uds/E=; b=YLbScsZLrxTimrXI5lPerLyOLWAbNRw7/E5366+T4qxp0fKETpreuJDL7iGRuCn81W6c5K yniRQ40h31fuTERYOLL//oMaBFFAxCbOxHWXv6JbUe/xTdmlNF/D2HntN8bOlyROBAm9ez 6NLOpfSkXTaqf1oqmirEb8R7Ri1TH50= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-433-FBl6eYJ5Nui1zOv_iC-6fw-1; Fri, 03 Sep 2021 07:56:54 -0400 X-MC-Unique: FBl6eYJ5Nui1zOv_iC-6fw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6370684A5E0; Fri, 3 Sep 2021 11:56:51 +0000 (UTC) Received: from redhat.com (unknown [10.39.193.241]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F080E5D9F0; Fri, 3 Sep 2021 11:56:24 +0000 (UTC) Date: Fri, 3 Sep 2021 12:56:22 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH 02/28] glib-compat: Introduce g_memdup2() wrapper Message-ID: References: <20210903110702.588291-1-philmd@redhat.com> <20210903110702.588291-3-philmd@redhat.com> <04ba0442-08ca-bf88-3f04-0be00c11bd1b@virtuozzo.com> MIME-Version: 1.0 In-Reply-To: <04ba0442-08ca-bf88-3f04-0be00c11bd1b@virtuozzo.com> User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -12 X-Spam_score: -1.3 X-Spam_bar: - X-Spam_report: (-1.3 / 5.0 requ) DKIMWL_WL_HIGH=-0.392, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Fam Zheng , Peter Maydell , Li Zhijian , "Michael S. Tsirkin" , Jason Wang , Christian Schoenebeck , qemu-devel@nongnu.org, Peter Xu , Gerd Hoffmann , Alexandre Iooss , Eric Blake , qemu-block@nongnu.org, Shannon Zhao , John Snow , Helge Deller , David Hildenbrand , Markus Armbruster , "Gonglei \(Arei\)" , Michael Roth , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Laurent Vivier , Thomas Huth , Eduardo Habkost , Stefan Weil , Richard Henderson , Greg Kurz , Yuval Shaia , Alex Williamson , qemu-arm@nongnu.org, Igor Mammedov , Alex =?utf-8?Q?Benn=C3=A9e?= , David Gibson , Kevin Wolf , Laurent Vivier , Zhang Chen , Hanna Reitz , qemu-ppc@nongnu.org, Paolo Bonzini , Mahmoud Mandour Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Sep 03, 2021 at 02:51:21PM +0300, Vladimir Sementsov-Ogievskiy wrote: > That was most probably already discussed, so sorry my question: > > Why we can't just do > > #if ! GLIB_CHECK_VERSION(2, 68, 0) > static inline gpointer g_memdup2(gconstpointer mem, gsize byte_size) > { > gpointer new_mem; > > if (mem && byte_size != 0) { > new_mem = g_malloc(byte_size); > memcpy(new_mem, mem, byte_size); > } else { > new_mem = NULL; > } > > return new_mem; > } > #endif > > ? This doesn't play with GLIB_VERSION_MAX_ALLOWED - any use of g_memdup2 will trigger compile warnings since we're using an API that only exists in a glib version newer than our declared baseline. The inline wrapper + macro is a trick that lets us backport new features, while avoiding the compile warnings. This is documented in the include/glib-compat.h file that Philippe is modifying. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|