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: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 6D08D1F462 for ; Mon, 29 Jul 2019 21:08:42 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version:content-type; q=dns; s=default; b=HQTX1 az8bCkqIMyULDGGxaDY25pZ8lbP7HhIXkgWivMNyr4OsbR14ydLL4nFuirwuJhNd uW0hzZd0x6NdqkxktdvjIwUoQW2+X6RA2hHycDoYhJs/XWBMMocb0h1nK+bPxYIx FEsTlPvcibCL4BvF+Ws0WPj7kZOxLdazBjtTx4= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version:content-type; s=default; bh=DvT6/U769cc 7+uzo52VJjexeFDo=; b=sP+XAHjeXz6aOrRQpNK6OOFQS0qvHxGQC1IkZTluzJ2 NI5VSPphTaL+u4QDFPrk/3Jq7d6Vog7cHxO17D3bn9mvk7xkSRagNKpsrVWshL3r MucioRyn8ep6V7uuU7b8+AjhcCWFnC5G3DTiYZZHb6MvpmqezXN86UKatuAUIhuU = Received: (qmail 58870 invoked by alias); 29 Jul 2019 21:08:40 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 58862 invoked by uid 89); 29 Jul 2019 21:08:39 -0000 Authentication-Results: sourceware.org; auth=none X-HELO: relay1.mentorg.com Date: Mon, 29 Jul 2019 21:08:33 +0000 From: Joseph Myers To: Adhemerval Zanella CC: Subject: Re: Accelerating Y2038 glibc fixes In-Reply-To: Message-ID: References: <20190712072103.D3DBC24003A@gemini.denx.de> <874l3mjgi6.fsf@oldenburg2.str.redhat.com> <20190716145216.1C7CE240085@gemini.denx.de> <875zo0911b.fsf@oldenburg2.str.redhat.com> <20190717160021.75EB224003E@gemini.denx.de> <87h87k7ilf.fsf@oldenburg2.str.redhat.com> <20190717181811.5902cd5e@jawa> <43e70b10-c1a1-ca79-b596-60616c8f5ad6@linaro.org> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" On Mon, 29 Jul 2019, Adhemerval Zanella wrote: > I think it would be easier than what you described because we won't need > to actually to add any header redefinition, all symbol affect will just > use the new time_t regardless of the ABI. The compat implementation will > use an internal-only type to use the old one. > > What it would require is to add compat implementations with a different > type, time32_t for instance. Something like: That seems much harder to implement through incremental development, whereas with _TIME_BITS=64 things can readily be implemented incrementally (adding 64-bit functions one-by-one with 32-bit ones as wrappers - already done for various mktime / timezone functions, for example - with only the final addition of _TIME_BITS=64 support in the headers and exporting symbols at public symbol versions needing to be one big monolithic patch). > I don't have a strong opinion if a patch proposal use the _TIME_BITS=32 > as a initial transition to enable time64 support, however I see no point > in make it available either on a release point neither in long term. The point is _TIME_BITS=64 as an API, not _TIME_BITS=32. Since the change to flip the default is small, I don't think it's very significant whether or not there is a release where the default is 64-bit but _TIME_BITS=32 is available as well (whereas having _TIME_BITS=64 available before it becomes the default is a practical matter of both reviewability and allowing users to plan the timing of their own transition to 64-bit times). -- Joseph S. Myers joseph@codesourcery.com