Path: csiph.com!weretis.net!feeder8.news.weretis.net!eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Tim Rentsch Newsgroups: comp.lang.c Subject: Re: Dymamic arrays: memory management and naming Date: Mon, 25 Sep 2023 23:41:35 -0700 Organization: A noiseless patient Spider Lines: 47 Message-ID: <86o7hpiggw.fsf@linuxsc.com> References: <20230909132336.99cdb303ad685bc1e40f92df@gmail.moc> <86ediwmk8b.fsf@linuxsc.com> <20230919011018.d9ed14da6e842291d47b69d7@gmail.moc> <86jzsmkqyu.fsf@linuxsc.com> <20230924003915.51bb21339ab1c551eba59162@gmail.moc> <20230924081911.947@kylheku.com> <20230925155845.139@kylheku.com> <86sf71itgt.fsf@linuxsc.com> <87msx9u09c.fsf@nosuchdomain.example.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: dont-email.me; posting-host="52bf0d5ee5119c0cfc0137a030202cf0"; logging-data="2515389"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19BFEsSaEYfiV99WtKf67+T3R7DxtNaxDM=" User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.4 (gnu/linux) Cancel-Lock: sha1:VGnzui2jBsFzDlYwk1r8GMa0Kxw= sha1:CgTQuJ5eyXP5RrLqqceBvIPIzlw= Xref: csiph.com comp.lang.c:176417 Keith Thompson writes: > Tim Rentsch writes: > >> Kaz Kylheku <864-117-4973@kylheku.com> writes: >> >>> On 2023-09-24, Kaz Kylheku <864-117-4973@kylheku.com> wrote: >>> >>>> h only makes sense if you're passing a signed argument and want >>>> it printed as unsigned. Say we have 16 bit short and 32 bit int. >>>> Then "%u"/(short) -1 will print as 429496725, whereas >>>> "%hu"/(short) -1 will obtain the desired 65535. >>> >>> There is something I had neglected to mention: the use of h for >>> portability >>> >>> If we have "%u" paired with an unsigned short, argument we have a >>> mismatch on a large number of platforms, where unsigned short >>> promotes to int. The %u specifier wants unsigned int. >> >> A %u conversion specification is always okay for an unsigned >> short argument, regardless of whether the argument promotes to >> int or to unsigned int. Reading an integer-typed variadic >> argument with the corresponding type of the other signedness >> is allowed when the argument value is representable in both >> types, which it always will be in this case even if unsigned >> short promotes to int. > > Agreed, but unfortunately the standard doesn't quite say that in > normative text -- until C23, as I discovered while writing this. > [...] My position is that this rule was intended since at least C99 (and perhaps earlier) but was not expressed at unambiguously as one might like. Also I believe there is support for this view if one consults various historical documents done by the ISO C committee. Also I think it is rather pointless to debate whether the C standard does or does not "say that in normative text" when the normative text that is there lends itself to different interpretations. We all agree on what words are used; what the words mean in this case is more a subjective reaction than an objective fact. And is pretty much beside the point since what was intended and what was understood is the same for most of the people who are familiar with the C standard.