From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [iproute PATCH RFC] libnetlink: introduce DECLARE_NLREQ Date: Sun, 29 Nov 2015 12:07:52 -0800 Message-ID: <20151129120752.73834f50@xeon-e3> References: <1448544365-23153-1-git-send-email-phil@nwl.cc> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Cc: To: Phil Sutter Return-path: Received: from mx0a-000f0801.pphosted.com ([67.231.144.122]:38959 "EHLO mx0a-000f0801.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752126AbbK2UHs (ORCPT ); Sun, 29 Nov 2015 15:07:48 -0500 In-Reply-To: <1448544365-23153-1-git-send-email-phil@nwl.cc> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 26 Nov 2015 14:26:05 +0100 Phil Sutter wrote: > This macro aims to simplify most netlink users' pattern to prepare a > request, which is to create an unnamed struct and initialize it: > > | struct { > | struct nlmsghdr n; > | struct whatever foo; > | char buf[arbitrary number]; > | } req; > | > | memset(&req, 0, sizeof(req)); > | req.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct whatever)); > | req.n.nlmsg_flags = NLM_F_REQUEST; > > Having this patch applied, the above can be replaced by a static > initializer like so: > > | DECLARE_NLREQ(req, n, struct whatever foo, arbitrary number); > > There is an added benefit, as well: Due to explicit alignment, the > requested tailroom is really as big as requested no matter what size > struct whatever really is. > > Signed-off-by: Phil Sutter > --- > This patch is RFC because I want to wait for peer review and upstream > acceptance before sending in the big refactoring patch itself. > --- > include/libnetlink.h | 11 +++++++++++ > 1 file changed, 11 insertions(+) I am not a fan of complex macros. But netlink seems to get lots of them. You need to add more parens round arguments (like name). Really longterm would rather iproute2 switched to a cleaner library like libmnl