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=-3.1 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL,T_SCC_BODY_TEXT_LINE 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 2DA002B34D for ; Mon, 10 Jun 2024 15:06:36 +0200 (CEST) Received: (qmail 6116 invoked by uid 550); 10 Jun 2024 13:06:32 -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 26391 invoked from network); 10 Jun 2024 11:47:21 -0000 Date: Mon, 10 Jun 2024 14:47:04 +0300 From: Valery Ushakov To: musl@lists.openwall.com Message-ID: References: <4b595a5b-2164-4bf2-af8b-80992eb0a0fe@LBSD.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4b595a5b-2164-4bf2-af8b-80992eb0a0fe@LBSD.net> Subject: [musl] Re: Different results with regex.h between Musl and Libc On Mon, Jun 10, 2024 at 05:38:36 +0000, Nigel Kukard wrote: > Musl output (Alpine 3.20), musl-1.2.5-r1... > > The input '37' matches the pattern '^([0-9]*)?\.?([0-9]*)?$' > Match 0: 37 > Match 1: > Match 2: 37 > > Glibc output (ArchLinux), glibc 2.39+r52+gf8e4623421-1... > > The input '37' matches the pattern '^([0-9]*)?\.?([0-9]*)?$' > Match 0: 37 > Match 1: 37 > Match 2: I'm not sure what POSIX requires here. The closest I can find after skimming through "9. Regular Expressions" is 9.4.6 that ends with: An ERE matching a single character repeated by an '*', '?', or an interval expression shall not match a null expression unless this is the only match for the repetition or it is necessary to satisfy the exact or minimum number of occurrences for the interval expression. https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_04_06 I'm not sure what to read into the absense of the usual "or an ERE enclosed in parentheses" chorus here. > printf("Match %d: %.*s\n", i, matches[i].rm_eo - matches[i].rm_so, input + matches[i].rm_so); Nit-pick: regoff_t may be wider than int (expected by '*'). E.g. your test program prints nothing for all those %.* on NetBSD/macppc (with the appropriate cast it prints 37/37/), as regoff_t is 64-bit (very old posix required regoff_t to be at least as wide as off_t). It will probably crash on a little-endian 32-bit NetBSD system, b/c the zero MSW of a 64-bit regoff_t will be interpreted as the argument for %s. -uwe