From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4 Received: from second.openwall.net (second.openwall.net [193.110.157.125]) by inbox.vuxu.org (Postfix) with SMTP id 88D7D21502 for ; Mon, 25 Mar 2024 19:02:03 +0100 (CET) Received: (qmail 20287 invoked by uid 550); 25 Mar 2024 17:57:17 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 20255 invoked from network); 25 Mar 2024 17:57:16 -0000 Date: Mon, 25 Mar 2024 14:02:08 -0400 From: Rich Felker To: Alexander Weps Cc: musl@lists.openwall.com Message-ID: <20240325180208.GF4163@brightrain.aerifal.cx> References: <20240324192258.GY4163@brightrain.aerifal.cx> <-svm5EdX4OFN9hKzgS2FP6N1lgUGjT7edQONkAfCywgsRitwT6Vw22W3sUUGY_pnKGIXBKlujMZhPCDkJAMCYbBA5uF-IYgzhj8WB0wBE-A=@pm.me> <4YlR0YRqzZlDIOVv6SP8UDoop89n8u7BvQl_7eXNTvDZnogXMxG1z-TLGIBf-O4edUphddXGfADbk_d7Uzb37g5JoH7vOIvvNRMFDxPWZok=@pm.me> <20240325122113.GB4163@brightrain.aerifal.cx> <20240325131318.GD4163@brightrain.aerifal.cx> <20240325134252.GE4163@brightrain.aerifal.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240325134252.GE4163@brightrain.aerifal.cx> User-Agent: Mutt/1.5.21 (2010-09-15) Subject: Re: [musl] Broken mktime calculations when crossing DST boundary On Mon, Mar 25, 2024 at 09:42:53AM -0400, Rich Felker wrote: > On Mon, Mar 25, 2024 at 01:24:57PM +0000, Alexander Weps wrote: > > See below. > > > > AW > > > > > > On Monday, March 25th, 2024 at 14:13, Rich Felker wrote: > > > > > On Mon, Mar 25, 2024 at 12:55:28PM +0000, Alexander Weps wrote: > > > > > > > > If you take your test program and switch it to initialize with > > > > > tm_mday=31, then do -=1 instead of +=1, you'll find that it gives > > > > > 2011-12-29 01:00:00 -10 as well, only now it seems like the correct, > > > > > expected thing to happen. Any change to "fix" the case you're > > > > > complaining about would necessarily break this case. > > > > > > > > So (- day, +day): > > > > > > > > Musl: > > > > 2011-12-31 01:00:00 +14 > > > > 2011-12-29 01:00:00 -10 > > > > 2011-12-29 01:00:00 -10 > > > > > > > > Glibc: > > > > 2012-01-01 01:00:00 +14 > > > > 2011-12-31 01:00:00 +14 > > > > 2012-01-01 01:00:00 +14 > > > > > > > > Seems like musl doesn't even interpret the initial struct tm > > > > correctly in that case. It is off by day. > > > > > > > > Because December only had 30 days, 31s day after normalization is > > > > January 1st. > > > > > > > > > This is nonsense. December has a day 31, which you can clearly see > > > from the glibc output. For this particular year in this zone, with the > > > zone rule change, there are "only 30 days" in December, but they are > > > numbered 1-29 and 31, not 1-30. > > > > You confuse day of month which is represented in tm_mday with > > calendar day that is interpreted by strftime. > > > > You said to set tm_mday = 31, which would be January 1st after normalization. > > December 31s is 30th day of month represented as tm_mday = 30. > > OK, I meant tm_mday=31-1. Um, no, where did you get that idea? I just assumed you were right because I always forget which tm_* are off-by-1, but tm_mday is one-based not zero-based: int tm_mday; // day of the month -- [1, 31] (per the standard). So how did you end up getting the wrong thing? Are you even running the code you say you are? Rich