Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Keith Thompson Newsgroups: comp.lang.c Subject: Re: Unexpected error on x[0] != y[0] Date: Mon, 12 Jun 2017 09:23:46 -0700 Organization: None to speak of Lines: 24 Message-ID: References: <8ac725fb-f9d8-4332-b7d5-b29e13a1e0f3@googlegroups.com> <2175c337-f0e7-43f8-8e1c-67e1f17ef8cb@googlegroups.com> <70f7fb10-9ea8-1ea8-c5f2-299a4aad447f@verizon.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: mx02.eternal-september.org; posting-host="defc4e5ae30e31482245c2bebee97ffa"; logging-data="11657"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+k9XBVT0r5EtF4ZrFkAWSm" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) Cancel-Lock: sha1:zO67BY1P2JDoJ1g0QeOLPIZo7FM= sha1:+hen8Ca7q66XnQDiT4D+a4QQsws= Xref: csiph.com comp.lang.c:112050 "James R. Kuyper" writes: [...] > He's probably getting confused about 6.5.6p7, which describes the binary > + and - operators: "For the purposes of these operators, a pointer to an > object that is not an element of an array behaves the same as a pointer > to the first element of an array of length one with the type of the > object as its element type." > > So, he's off by one level of indirection. It's quite true that a pointer > to x is treated (for the purposes of those operators) as a pointer to an > array consisting of a single 'char'. A pointer to the initial element of such an array, not a pointer to the array itself. > However, x itself is not such an > array, and because it isn't such an array, does not automatically > convert into a pointer to the first element of that array. -- Keith Thompson (The_Other_Keith) kst-u@mib.org Working, but not speaking, for JetHead Development, Inc. "We must do something. This is something. Therefore, we must do this." -- Antony Jay and Jonathan Lynn, "Yes Minister"