From owner-freebsd-hackers@FreeBSD.ORG Tue Mar 4 15:56:15 2008 Return-Path: Delivered-To: hackers@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 6926F1065670; Tue, 4 Mar 2008 15:56:15 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from harmony.bsdimp.com (bsdimp.com [199.45.160.85]) by mx1.freebsd.org (Postfix) with ESMTP id 0CAFB8FC2A; Tue, 4 Mar 2008 15:56:14 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from localhost (localhost [127.0.0.1]) by harmony.bsdimp.com (8.14.2/8.14.1) with ESMTP id m24FqHj2071621; Tue, 4 Mar 2008 08:52:17 -0700 (MST) (envelope-from imp@bsdimp.com) Date: Tue, 04 Mar 2008 08:52:45 -0700 (MST) Message-Id: <20080304.085245.2040341894.imp@bsdimp.com> To: keramida@ceid.upatras.gr From: "M. Warner Losh" In-Reply-To: <20080304154542.GC61036@kobe.laptop> References: <20080304.083350.1661915009.imp@bsdimp.com> <20080304153651.I41184@fledge.watson.org> <20080304154542.GC61036@kobe.laptop> X-Mailer: Mew version 5.2 on Emacs 21.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: hackers@FreeBSD.org, rwatson@FreeBSD.org Subject: Re: Comments on pmake diffs for building on Linux X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 04 Mar 2008 15:56:15 -0000 In message: <20080304154542.GC61036@kobe.laptop> Giorgos Keramidas writes: : On 2008-03-04 15:38, Robert Watson wrote: : > On Tue, 4 Mar 2008, M. Warner Losh wrote: : > : >> : In most ports of FreeBSD parts to Linux that I've seen, the preferred solution : >> : has to been to bring the entire FreeBSD queue.h with you rather than relying : >> : on the native Linux queue.h. This is what we do for OpenBSM, for example; : >> : this also helps out when you get to Mac OS X, Solaris, etc, where all the : >> : queue.h's continue to vary in subtle ways. This depends a fair amount on a : >> : lack of header pollution in the OS's own include files, of course... : >> : >> I was rather hoping for something that could be used without any of that : >> nonsense... : > : > Sadly, nonsense seems to be the name of the game in software portability. : > Here's the broken autoconf garbage I use to pick out adequate queue.h's : > from inadequate ones: : > : > # sys/queue.h exists on most systems, but its capabilities vary a great deal. : > # test for LIST_FIRST and TAILQ_FOREACH_SAFE, which appears to not exist in : > # all of them, and are necessary for OpenBSM. : > AC_TRY_LINK([ : > #include : > ], [ : > : > #ifndef LIST_FIRST : > #error LIST_FIRST missing : > #endif : > #ifndef TAILQ_FOREACH_SAFE : > #error TAILQ_FOREACH_SAFE : > #endif : > ], [ : > AC_DEFINE(HAVE_FULL_QUEUE_H,, Define if queue.h includes LIST_FIRST) : > ]) : > : > Note that there are at least a couple of mostly stylistic bugs there (could : > use compile rather than link, definition description is poor, errors are : > inconsistent). :-) I found that on both Linux and Mac OS X, the queue.h's : > didn't have everything I wanted. : : Nice! Thank you Robert. Can I copy parts of this and add them to the : autoconf glue I'm adding now? : : To test just cpp(1) stuff, autoconf supports AC_PREPROC_IFELSE() too, : which I used when I tried writing a check for __FBSDID(): : : AC_PREPROC_IFELSE( : [AC_LANG_PROGRAM([[#include : #ifndef __FBSDID : #error No __FBSDID definition. : #endif]])], : [AC_DEFINE([HAVE_FBSDID_MACRO], [1], : [Define to 1 if you have the __FBSDID macro.])]) : : I can probably improve a bit the queue.h check using what you wrote : above and AC_PREPROC_IFELSE(). The alternative to uglifying the make sources with #ifdefs would be to just always use the compat includes when building... No autoconf needed, and minimal changes to the base make, if any. Warner