Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail
From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.lang.c
Subject: Re: Buffer contents well-defined after fgets() reaches EOF ?
Date: Mon, 10 Feb 2025 07:21:11 -0000 (UTC)
Organization: A noiseless patient Spider
Lines: 19
Message-ID: <voc9d7$13pam$2@dont-email.me>
References: <vo9g74$fu8u$1@dont-email.me> <vo9hlo$g0to$1@dont-email.me>
	<vo9khf$ggd4$1@dont-email.me> <vobf3h$sefh$2@dont-email.me>
	<vobjdt$t5ka$1@dont-email.me> <vobro1$u9fa$1@dont-email.me>
	<vobu9b$12bi8$1@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Injection-Date: Mon, 10 Feb 2025 08:21:11 +0100 (CET)
Injection-Info: dont-email.me; posting-host="8d964e1be02ec4fc321f0a3e4e27d15a";
	logging-data="1172822"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX18dgb9TJxbQ5UGlaVNTUc0f"
User-Agent: Pan/0.161 (Chasiv Yar; )
Cancel-Lock: sha1:/tAcw5KZUzScv1QNPNt7IYt7f3Q=
Bytes: 1926

On Sun, 9 Feb 2025 20:11:22 -0800, Andrey Tarasevich wrote:

> This manpage, for one example, is in full agreement with the standard
> 
> https://www.man7.org/linux/man-pages/man3/fgets.3p.html

Notice these two sentences would seem to contradict one another:

    A null byte shall be written immediately after the last byte read
    into the array. If the end-of-file condition is encountered before
    any bytes are read, the contents of the array pointed to by s
    shall not be changed.

> A practical experiment demonstrates that [supposedly] POSIX-obeying
> implementations do not write '\0' into the buffer in "immediate
> end-of-file" situations:
> https://coliru.stacked-crooked.com/a/3e672e6718dd388b

My test program does the same. I would say that settles it.