From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS3215 2.6.0.0/16 X-Spam-Status: No, score=-3.8 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by dcvr.yhbt.net (Postfix) with ESMTP id 61D131F403 for ; Tue, 11 Oct 2022 00:11:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230326AbiJKALR (ORCPT ); Mon, 10 Oct 2022 20:11:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230313AbiJKAKG (ORCPT ); Mon, 10 Oct 2022 20:10:06 -0400 Received: from cloud.peff.net (cloud.peff.net [104.130.231.41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F247229369 for ; Mon, 10 Oct 2022 17:09:54 -0700 (PDT) Received: (qmail 29583 invoked by uid 109); 11 Oct 2022 00:09:51 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Tue, 11 Oct 2022 00:09:51 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 14964 invoked by uid 111); 11 Oct 2022 00:09:52 -0000 Received: from coredump.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Mon, 10 Oct 2022 20:09:52 -0400 Authentication-Results: peff.net; auth=none Date: Mon, 10 Oct 2022 20:09:50 -0400 From: Jeff King To: Junio C Hamano Cc: git@vger.kernel.org, =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason Subject: Re: [PATCH v2 5/5] CodingGuidelines: recommend against unportable C99 struct syntax Message-ID: References: <20221010203800.2154698-1-gitster@pobox.com> <20221010203800.2154698-6-gitster@pobox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20221010203800.2154698-6-gitster@pobox.com> Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Mon, Oct 10, 2022 at 01:38:00PM -0700, Junio C Hamano wrote: > diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines > index 9598b45f7e..cbe0377699 100644 > --- a/Documentation/CodingGuidelines > +++ b/Documentation/CodingGuidelines > @@ -242,6 +242,10 @@ For C programs: > printf("%"PRIuMAX, (uintmax_t)v). These days the MSVC version we > rely on supports %z, but the C library used by MinGW does not. > > + . Shorthand like ".a.b = *c" in struct assignments is known to trip > + up an older IBM XLC version, use ".a = { .b = *c }" instead. See > + the 33665d98e6b portability fix from mid-2022. FWIW, the use of the word "assignment" here left me scratching my head. Reading 33665d98e6b, it is about struct initialization. C99 does allow assignment from a compound literal, like: foo = (struct some_struct){ .a = 1, .b = 2 }; but I don't think we have any examples in the current code (and I think we'd consider it a different feature for purposes of testing a weather balloon). -Peff