Date: Sat, 17 Jan 2015 11:43:08 -0800 From: John-Mark Gurney <jmg@funkthat.com> To: less xss <less.xss@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: ctrl-d appends characters to output Message-ID: <20150117194308.GH1949@funkthat.com> In-Reply-To: <CAGcjGpP0t3%2BcJLRHS5Ggfjao9Vcy0xosAg2KqBWgVA_NtKoNgA@mail.gmail.com> References: <CAGcjGpP0t3%2BcJLRHS5Ggfjao9Vcy0xosAg2KqBWgVA_NtKoNgA@mail.gmail.com>
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less xss wrote this message on Sat, Jan 17, 2015 at 12:59 -0500:
> I've searched around quite a bit with no luck on this matter. I currently
> have an issue where I send EOF (ctrl-d) to some simple K&R2 exercises and
> the terminal returns the D character appended to my data when EOF is sent.
> I wish to prevent any and all extra characters from being appended and I
> would also like to understand why it's happening. The following code
> is an example exercise from K&R2 that yield said problem.
>
> #include <stdio.h>
>
> int main() {
> double nc;
>
> for (nc = 0; getchar() != EOF; ++nc) {
> ; /* syntactic null statement */
> }
>
> printf("%.0f\n", nc);
> }
>
> $ ./a.out
> 0D
> $
This problem exists on pretty much any Unix based platform and is not
FreeBSD specific...
The D is not getting appended to your output... If you changed your
printf to include a space or two before the new line, you wouldn't
see the D... the D is left after the kernel echoed ^D in response to your
ctrl-D. If you redirect the output to a file and examined the output,
there would be no D in your output... Or if you provided input from
another source that didn't require an EOF to trigger it, such as:
$echo | ./t
1
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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