From: Ivan Kozik <ivan@ludios.org>
To: cygwin@cygwin.com
Subject: Wrong file position after writing 65537 bytes to block device
Date: Sat, 16 Dec 2017 06:13:00 -0000 [thread overview]
Message-ID: <CAKyntiKrJBZRTSDdAbDTuaS3NNoGLD3OaM8M7V7Fq3EroArXxg@mail.gmail.com> (raw)
Hello,
I have discovered that if you write 65536 + 1 bytes to a block device
in cygwin, the file position can become 65536 + 512.
With /dev/sdc as a throwaway USB block device:
(cygwin_write.c is pasted below)
# gcc -O2 -Wall -o cygwin_write cygwin_write.c
# ./cygwin_write /dev/sdc
66048
I am running 64-bit cygwin 2.9.0 on an updated Windows 8.1. I saw the
same results with an 8TB drive and a 512MB USB stick.
Best regards,
Ivan
cygwin_write.c:
#include <stdio.h>
int main(int argc, char *argv[]) {
FILE *f = fopen(argv[1], "w");
char x[65536 + 1];
fwrite(x, 1, 65536 + 1, f);
printf("%ld", ftell(f));
return 0;
}
--
Problem reports: http://cygwin.com/problems.html
FAQ: http://cygwin.com/faq/
Documentation: http://cygwin.com/docs.html
Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
next reply other threads:[~2017-12-16 2:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-16 6:13 Ivan Kozik [this message]
2017-12-18 16:32 ` Corinna Vinschen
2017-12-19 5:03 ` Steven Penny
2017-12-19 10:20 ` Corinna Vinschen
2017-12-19 16:36 ` Ivan Kozik
2017-12-19 17:43 ` Eric Blake
2017-12-19 18:18 ` Ivan Kozik
2017-12-19 18:36 ` Corinna Vinschen
2017-12-20 5:47 ` Ivan Kozik
2017-12-20 23:59 ` Kaz Kylheku
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAKyntiKrJBZRTSDdAbDTuaS3NNoGLD3OaM8M7V7Fq3EroArXxg@mail.gmail.com \
--to=ivan@ludios.org \
--cc=cygwin@cygwin.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).