DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org CC74C3848340
To: "newlib@sourceware.org" <newlib@sourceware.org>
CC: Corinna Vinschen <vinschen@redhat.com>,
        "cygwin@cygwin.com"
 <cygwin@cygwin.com>
Subject: RE: [EXTERNAL] Re: rand is not ISO C compliant in Cygwin
Thread-Topic: [EXTERNAL] Re: rand is not ISO C compliant in Cygwin
Thread-Index: AQHaFjxgZVRaEdkyvUyAIpZTVu4rWrB4TfMAgAADugCAAByjAIAAAVog
Date: Mon, 13 Nov 2023 16:44:08 +0000
Deferred-Delivery: Mon, 13 Nov 2023 16:44:07 +0000
Message-ID: <DM8PR09MB7095FD4287584FC53200831CA5B3A@DM8PR09MB7095.namprd09.prod.outlook.com>
References: <9938355.c9vzh5UkMf@nimes> <ZVIv3oq8UU6GTa0n@calimero.vinschen.de>
 <4746602.Hd9D3QOfv1@nimes> <ZVI06HnJE+r1CwFB@calimero.vinschen.de>
 <ZVJM7g9smHGMN7QH@calimero.vinschen.de>
In-Reply-To: <ZVJM7g9smHGMN7QH@calimero.vinschen.de>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?us-ascii?Q?ouR1+tgaDGpTmqEB/YuFofsAlXBLOs4ryxKD9f7P2D/FDejDT1Wqplf91L5F?=
 =?us-ascii?Q?MGnsgnUDr3pavje/lrxBDyMdedr3HUdG0zJ8dz2MqpI5MGduAuSFVWR2low7?=
 =?us-ascii?Q?nRrvztfppRTFJq9nmIjvzAdlurb66lt5ISKGRM8DVKKqkQ15ll0L9+S/PIhQ?=
 =?us-ascii?Q?z8uL77VxnBKY49TBSyRVbDzSevFs9XTXsetIEYdRe5+wzqRFP9FF99HwBhnz?=
 =?us-ascii?Q?/Eco8uFtZ/eK27Ixid1xfoykzrlBYCyFUez1O3jLphX+JkgfldBhP0soKbnP?=
 =?us-ascii?Q?ee+8ZxN9wirvJxO4c5KyVS0xWTtQiNhWald/Z94/UnTDLCN1VPPlo4zJHB+V?=
 =?us-ascii?Q?KFckAFvDmZMMB8vW9CySlkO/ULpW9skxlbTuZZztAj0cUMvkZLN+xrnlw6Cx?=
 =?us-ascii?Q?c0ggXkRkI93ouvFfet/2eXBD9o9YXGDaZgWV8oI1UBEjOkjsfEaU7mN6yAFU?=
 =?us-ascii?Q?Lx5mDirOmy0jF2KVJ8sNc5DVDNuMAR3eA1bL/agTBr3zieXgINwI6/ADTqbY?=
 =?us-ascii?Q?wqbTcRMVwFLdfyPHzihnGNMpAmL4203+eB3RVOlMSttk/xCTVnwz+IJPvhsx?=
 =?us-ascii?Q?P1QmeoCChgikJIWwNLqLLsJ1IHo7ej1lBjPWU4RkEb5CHoMy8CLLkQZkj6rv?=
 =?us-ascii?Q?zBtRbbQJxs1y3jPk+53BmauWDbnX8qrAqlLzBF2o86EtOjFinBuw6C5Ryy2z?=
 =?us-ascii?Q?Xn/dfGWO04LofsBHxN4QmieEcfRQmvb84FeS5WBc3JmTrLPS8ybOWE8BeuLe?=
 =?us-ascii?Q?z4DXP18HYM6Q1RYz0z0vsVx+Mo0NGAKzp7JchUNapPMr6XQPevm3nyGcRVCp?=
 =?us-ascii?Q?wtQu0UrWwKZob3H5xCvyjR6K6Tm/0DXB/j/4SY+eRRv1nwRBxmA661SKCr0H?=
 =?us-ascii?Q?aIxLb118IorE868S3yEkiPplTCMhPqzf3+5cGh/H+h05cv3nM+Wzo0d/MOyd?=
 =?us-ascii?Q?dn+mARzXL3vX7jNOPsI07Rkonr/YaE9sWlpyxLSh2sc7nEu+0DX00O54SXK/?=
 =?us-ascii?Q?UlZwPGz5TCkU8HjoPuhOmO56bQxOh4+8U52w4wm/TN/GwfH53ANpNZFUvpX/?=
 =?us-ascii?Q?S0Tpaf63xihDk7gMb/+Oyw1nhtIi2G5AmPoTL0Z/JFv/v0V0e90TPwNVYiQb?=
 =?us-ascii?Q?wKbSSJwP0BD6+IA1YviCOwyD0QFrbP2oxlbdm1xQae+8uP9maAbMN5yz1vqB?=
 =?us-ascii?Q?Z6xZR2gQXxqwfEM4H6mW+hMkAtvdbJPn2+RD2mNFMGWw6iA50jy6s36CQLn2?=
 =?us-ascii?Q?BRSuey1TaAZ1SpoPRj8zyvERKTNwvwo6q4eCT/i8C8AuuA7I8Km2ZeTPIOGB?=
 =?us-ascii?Q?hY7zGmmzuVXQPdJT/Y3YBaW50UCnNmJMZQtLJlOviFxWEqlxsA32rQtbQcZW?=
 =?us-ascii?Q?TPHV3RRTYwh7tbcHCRv9ADOMFnonbQ8vgt6/g4HDiRvBZAjsT5RKUtftm4EV?=
 =?us-ascii?Q?Uis1MentzNKCzE7CDinl3oPIjQLX7MSMe4UX4QEt+zWQFUV2SenSdRfTA4dy?=
 =?us-ascii?Q?N/7IIwmYKcLjAdFQxJ27BAJzVmibhzm6IfprqJvmqhGK2OGnT/vnEQr58nT6?=
 =?us-ascii?Q?C21cFT6+ykXKMQoduVQ=3D?=
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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
X-OriginatorOrg: ncbi.nlm.nih.gov
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: DM8PR09MB7095.namprd09.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 709331a8-ca29-4c29-adcc-08dbe467cf8a
X-MS-Exchange-CrossTenant-originalarrivaltime: 13 Nov 2023 16:44:31.7672 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 14b77578-9773-42d5-8507-251ca2dc2b06
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR09MB10624
X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00, DKIM_SIGNED,
 DKIM_VALID, DKIM_VALID_EF, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE,
 T_SPF_HELO_PERMERROR autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
 server2.sourceware.org
X-BeenThere: cygwin@cygwin.com
X-Mailman-Version: 2.1.30
List-Id: General Cygwin discussions and problem reports <cygwin.cygwin.com>
List-Archive: <https://cygwin.com/pipermail/cygwin/>
List-Post: <mailto:cygwin@cygwin.com>
List-Help: <mailto:cygwin-request@cygwin.com?subject=help>
List-Subscribe: <https://cygwin.com/mailman/listinfo/cygwin>,
 <mailto:cygwin-request@cygwin.com?subject=subscribe>
From: "Lavrentiev, Anton \(NIH/NLM/NCBI\) \[C\] via Cygwin" <cygwin@cygwin.com>
Reply-To: "Lavrentiev, Anton \(NIH/NLM/NCBI\) \[C\]" <lavr@ncbi.nlm.nih.gov>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Sender: "Cygwin" <cygwin-bounces+archive-cygwin=delorie.com@cygwin.com>

IMHO:

>   2. A different sequence

The word "different" in this context is ambiguous: is it "unrelated" as a generator, or is it "not the same" sequence of the actual numbers?

> I read this as the newlib technique being one way of correctly implementing rand/srand, no?

If the first, then yes; but if the second, then no.

The problem with the first approach is, however, is the inability to adequately randomize your code (e.g. for testing).

You call srand() in the main() thread, and then spawn threads thinking they will inherit the randomization; but in fact, they all start off the same number sequence, regardless.

Anton Lavrentiev
Contractor NIH/NLM/NCBI


-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple