From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755019AbaIDR6s (ORCPT ); Thu, 4 Sep 2014 13:58:48 -0400 Received: from mail-ie0-f180.google.com ([209.85.223.180]:38465 "EHLO mail-ie0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754987AbaIDR6q (ORCPT ); Thu, 4 Sep 2014 13:58:46 -0400 Message-ID: <5408A84C.1090806@gmail.com> Date: Thu, 04 Sep 2014 13:58:36 -0400 From: Austin S Hemmelgarn User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Alexander Holler , Peter Zijlstra CC: Borislav Petkov , =?ISO-8859-15?Q?M=E5ns_Rullg=E5rd?= , Steven Rostedt , Christopher Barry , linux-kernel@vger.kernel.org Subject: Re: OT: Open letter to the Linux World References: <20140812153812.2923046a@monolith.infinux.org> <20140812202129.GA20344@home.goodmis.org> <20140813082756.GB2923@twins.programming.kicks-ass.net> <20140813090013.GA20581@pd.tnic> <53F242D1.4050506@ahsoftware.de> <20140904075453.GK3190@worktop.ger.corp.intel.com> <54083C0F.1040807@ahsoftware.de> <540878D4.7080501@gmail.com> <5408A175.3090400@ahsoftware.de> In-Reply-To: <5408A175.3090400@ahsoftware.de> Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary="------------ms080904080504010903050304" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a cryptographically signed message in MIME format. --------------ms080904080504010903050304 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable On 2014-09-04 13:29, Alexander Holler wrote: > Am 04.09.2014 16:36, schrieb Austin S Hemmelgarn: >> On 2014-09-04 06:16, Alexander Holler wrote: >>> >>> It's a myth that C++ ends up in bigger code than C. At least in my >>> experience. Especially when the latest additions to C++ are in effect= >>> (like the move-semantics in C++11 I like quiet a lot and which you ge= t >>> almost for free (by changing nothing) when you use the STL). Thread >>> support is now also standardized (in C++11), quiet nice to use. >=20 >> Assuming you are writing in a standalone environment (no standard >> libraries), then yes, your code will usually be about the same size >> (unless you go way overboard with the object-oriented stuff); but the >> runtime is larger in almost all non-standalone environments, and there= >> are some cases that code does end up larger in C++. A lot of 'Clean C= ' >> (stuff written so that it compiles correctly as C, C++ and Objective C= ) >> that I have seen seems to end up larger (by about 4-6%) when built as >> C++ (although it usually does much worse as Objective C). >=20 > There are always corner cases and I never would use some "Clean C" code= > to compare sizes of C and C++. There is a whole lot of stuff you just > can't, shouldn't or wouldn't do when using C instead of C++. >=20 > And just throwing in some numbers without any explanation about feature= s > (like exceptions), optimizations and so on you've enabled for the tests= > you used to get those numbers, doesn't work. ;) >=20 > I can't really comment on what you mean with "standalone environment" o= r > "non-standalone environment", as I don't know what you mean with that. > But if several programms share e.g. the stuff which is in libstdc++. > you'll get a lot of size back when compared with C-only programms where= > everyone invents the wheel again and again. By standalone environment, I mean no libraries, no libc[++], no external dependencies, and in the case of a lot of kernel programming, no built-ins. A OS kernel HAS to be written like that, and it's easier to do that in C than C++. I doubt that you have ever looked at any source code for Windows drivers, but Windows is written in C++, and they still are just as mind-numbingly insane as some of the poorly maintained, vendor originated Linux drivers. Not all C is like the Linux kernel, and in fact, if you use Linux, probably more than half of your user-space programs were written in C. 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