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bug#11631: closed (Re: bug#11631: Head command does not position file po
From: |
Jim Meyering |
Subject: |
bug#11631: closed (Re: bug#11631: Head command does not position file pointer correctly for negative line count) |
Date: |
Wed, 06 Jun 2012 10:02:18 +0200 |
Anoop Sharma wrote:
> 1. The comment in code - "Don't bother testing for failure for such a
> small amount. Any failure will be detected upon close." may be
> re-looked too, since we are now lseeking after it.
>
> What if we change plain fwrite to:
> if (fwrite (buffer, 1, n + 1, stdout) < (n + 1))
> error (EXIT_FAILURE, errno, _("write error"));
>
> 2. Maybe using lseek with SEEK_CUR in place of SEEK_SET would reflect
> logic better.
Regarding #1, thanks for the suggestion. You're right.
I've written a complete patch in your name, below, adding a commit
log and removing the unnecessary parentheses around "n + 1".
In general, I much prefer a patch to a suggestion like that.
The advantage to you is that if you describe precisely enough
(usually requires a patch), then you're listed as the author
of the commit. If you also take the time to write a commit
log entry like I did below, then that's even better.
See the file, HACKING, for instructions on how to do that
as well as general contribution guidelines.
Regarding #2, please be precise and write/post a patch.
>From 7fcfa754f1ff92d4fed1495a05574b8e47c3b4fb Mon Sep 17 00:00:00 2001
From: Anoop Sharma <address@hidden>
Date: Wed, 6 Jun 2012 09:42:09 +0200
Subject: [PATCH] head: diagnose write failure immediately, given new lseek
use
Inserting the lseek call (commit v8.17-13-g295ee52) rendered
inaccurate the comment/code that refrained from diagnosing the
failure of the just-preceding fwrite.
* src/head.c (elide_tail_lines_seekable): Remove now-erroneous
comment, and diagnose fwrite failure.
---
src/head.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/src/head.c b/src/head.c
index c13c064..ffe7c74 100644
--- a/src/head.c
+++ b/src/head.c
@@ -663,10 +663,9 @@ elide_tail_lines_seekable (const char *pretty_filename,
int fd,
}
/* Output the initial portion of the buffer
- in which we found the desired newline byte.
- Don't bother testing for failure for such a small amount.
- Any failure will be detected upon close. */
- fwrite (buffer, 1, n + 1, stdout);
+ in which we found the desired newline byte. */
+ if (fwrite (buffer, 1, n + 1, stdout) < n + 1)
+ error (EXIT_FAILURE, errno, _("write error"));
/* Set file pointer to the byte after what we've output. */
if (lseek (fd, pos + n + 1, SEEK_SET) < 0)
--
1.7.11.rc1
- bug#11631: Head command does not position file pointer correctly for negative line count, (continued)
- bug#11631: Head command does not position file pointer correctly for negative line count, Voelker, Bernhard, 2012/06/05
- bug#11631: Head command does not position file pointer correctly for negative line count, Jim Meyering, 2012/06/05
- Message not available
- bug#11631: Head command does not position file pointer correctly for negative line count, Jim Meyering, 2012/06/05
- bug#11631: Head command does not position file pointer correctly for negative line count, Jim Meyering, 2012/06/05
- bug#11631: Head command does not position file pointer correctly for negative line count, Pádraig Brady, 2012/06/05
- bug#11631: Head command does not position file pointer correctly for negative line count, Jim Meyering, 2012/06/05
- bug#11631: Head command does not position file pointer correctly for negative line count, Jim Meyering, 2012/06/05
Message not available
- bug#11631: closed (Re: bug#11631: Head command does not position file pointer correctly for negative line count), Anoop Sharma, 2012/06/06
- bug#11631: closed (Re: bug#11631: Head command does not position file pointer correctly for negative line count),
Jim Meyering <=
- bug#11631: closed (Re: bug#11631: Head command does not position file pointer correctly for negative line count), Eric Blake, 2012/06/06
- bug#11631: closed (Re: bug#11631: Head command does not position file pointer correctly for negative line count), Jim Meyering, 2012/06/06
- bug#11631: closed (Re: bug#11631: Head command does not position file pointer correctly for negative line count), Anoop Sharma, 2012/06/07
- bug#11631: closed (Re: bug#11631: Head command does not position file pointer correctly for negative line count), Jim Meyering, 2012/06/07
- bug#11631: closed (Re: bug#11631: Head command does not position file pointer correctly for negative line count), Anoop Sharma, 2012/06/08
- bug#11631: closed (Re: bug#11631: Head command does not position file pointer correctly for negative line count), Eric Blake, 2012/06/07
- bug#11631: closed (Re: bug#11631: Head command does not position file pointer correctly for negative line count), Anoop Sharma, 2012/06/08
bug#11631: closed (Re: bug#11631: Head command does not position file pointer correctly for negative line count), Jim Meyering, 2012/06/06