Path: csiph.com!eternal-september.org!feeder.eternal-september.org!nntp.eternal-september.org!.POSTED!not-for-mail From: Tim Rentsch Newsgroups: comp.lang.c Subject: Re: A thought of C Date: Wed, 22 Apr 2026 20:39:39 -0700 Organization: A noiseless patient Spider Lines: 31 Message-ID: <86v7di4a6c.fsf@linuxsc.com> References: <3a3462bdd72c4ed9d392a78b7d369a7b5ccc3b04.camel@gmail.com> <10rtdpd$2g1i0$1@dont-email.me> <10rth24$2h2ls$1@dont-email.me> <10rtnud$2jfm5$1@dont-email.me> <10s01e1$384ct$1@dont-email.me> <10s06q2$39rhn$1@dont-email.me> <10s2a2u$3t0f5$1@dont-email.me> <10s2fhc$3ug5h$1@dont-email.me> <10s2h5f$3uctl$1@dont-email.me> <10s2oq0$19am$1@dont-email.me> <10s2tfe$2lvm$1@dont-email.me> <10s34f6$542f$1@dont-email.me> <10s3akj$7ajg$1@dont-email.me> <10s3otn$bk6v$1@dont-email.me> <10s5atn$2sck7$1@paganini.bofh.team> <86ik9j63hc.fsf@linuxsc.com> <10sal8n$2967c$2@dont-email.me> <20260422185252.00001a9b@yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Date: Thu, 23 Apr 2026 03:39:42 +0000 (UTC) Injection-Info: dont-email.me; posting-host="096db26766e75ae3d0da9ffd77dfc80c"; logging-data="2902200"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+ZSyoWBEHDlS7SwLo6XqzrboRmpE77nWU=" User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.4 (gnu/linux) Cancel-Lock: sha1:bgmEmwqDB+VY6oP45Udm8xKkaDk= sha1:Ixiqr1l58PrT8Osc8hAijN7dl8E= Xref: csiph.com comp.lang.c:397824 Michael S writes: > On Wed, 22 Apr 2026 15:16:56 +0100 > Bart wrote: > >> On 22/04/2026 05:09, Tim Rentsch wrote: >> >>> antispam@fricas.org (Waldek Hebisch) writes: >>> >>>> You look at trivial example, where AFAICS the best answer is: >>>> "Compiler follows general rules, why should it make exception for >>>> this case?". Note that in this trivial case "interesting" >>>> behaviour could happen on exotic hardware (probably disallowed >>>> by C23 rules, but AFAICS legal for earlier C versions). >>> >>> The kinds of behavior Bart is asking about has been undefined >>> behavior for just over 15 years, since 2011 ISO C. >> >> So what was it between 1972 and 2011? > > My record at guessing exact meaning of Tim's statements is not > particularly good, but I'll try nevertheless. > > Tim seems to suggest that function foo() below had defined behavior > (most likely of returning 1) in C90 and C99, then it became undefined in > C11 and C17 then again became defined in C23. > For years 1972 to 1989 Tim probably thinks that there is no sufficient > data to answer your question. I'm curious to know what you think of my answer now that I have written one. :)