From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 5675FA0A02; Wed, 24 Mar 2021 22:55:50 +0100 (CET) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id D530240684; Wed, 24 Mar 2021 22:55:49 +0100 (CET) Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by mails.dpdk.org (Postfix) with ESMTP id C692C4067B for ; Wed, 24 Mar 2021 22:55:48 +0100 (CET) Received: by linux.microsoft.com (Postfix, from userid 1086) id 1183920B5680; Wed, 24 Mar 2021 14:55:48 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 1183920B5680 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1616622948; bh=l7OFOcaJAsEqQ3MuuhRMYGBVNfQBa/jac9HCfUt/uBM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Cg6icJ289SyhpXxDqhSpWXxlm2fvXkUWSY6VamtYuAvVEcBWmIuo/QhPEdgFoy5Rl JIp3Qv53AIm8JJUjMYj5dgqNJJclJsfLnmqoHKH71DSuuLqQN5UDS93cXoDZyFdkTu QT9fbhEyUcUsj/17KO5sWv9VanOtATq16JGIjjNY= Date: Wed, 24 Mar 2021 14:55:48 -0700 From: Tyler Retzlaff To: Thomas Monjalon Cc: dev@dpdk.org, david.marchand@redhat.com, bruce.richardson@intel.com, stephen@networkplumber.org, drc@linux.vnet.ibm.com Message-ID: <20210324215548.GA2272@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> References: <1616560011-31647-1-git-send-email-roretzla@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> <6578330.zVv2phWGOd@thomas> <20210324172841.GC14991@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> <11634428.8dEGKDZn2b@thomas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <11634428.8dEGKDZn2b@thomas> User-Agent: Mutt/1.5.21 (2010-09-15) Subject: Re: [dpdk-dev] [PATCH] eal: standard c++ forbids defining the keyword asm as a macro X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Wed, Mar 24, 2021 at 06:52:40PM +0100, Thomas Monjalon wrote: > 24/03/2021 18:28, Tyler Retzlaff: > > > > so to qualify. you mean maybe it is breaking compilation of c++ in a > > compiler that explicitly violates c++ standard when compiling c++? that > > would mean it is not a c++ compiler. > > The asm keyword is part of all C++ standards? > It seems asm is non-standard in C, > that's why we use __asm__. the keyword is standard the meaning of the keyword is implementation defined for both C and C++. though the C11 standard describes a "common implementation is via statement of the form ..." [J.5.10] > > in general i don't think it is a good practice to have dpdk introduce > > names into the application namespace unqualified, but the point you make > > is valid it can break c++ compilation if something was using this macro > > as a convenience to the compiler specific extension __asm__. there will > > be further issues with varying syntaxes that __asm__-style extensions > > take from compiler to compiler as well. > > Yes we need to make sure there is no specific extension involved. > Is C++ asm the same as the C __asm__? i don't think I can answer that as it depends on the compiler. there may be no implementation at all or different implementations for asm or __asm__. so basically neither form is portable (for an arch). though for __asm__ probably there is de-facto standardization around what gcc does and clang mimics. > > would you prefer that i change the preprocessor protection to include only > > windows? since i'm certain that this will break for any c++ compiler on > > windows the moment any stl header is included. > > No, C++ is probably the right scope. > > I don't know yet. I would like to understand the global picture, > and have it properly documented in this commit log. yep, no problem. i suspect we are probably the only ones using c++ and dpdk (though others can speak up if they do too) which may be why this has gone unnoticed until now.