11-22-2005
You want: each new line as it appears in the file, the full line, correct?
When a C program calls fwrite() or even write, the data is stored in the kernel, not the file. The device I/O happens whenever the kernel decides to do it or is asked to do it.
The kernel also writes data is chunks, not in lines. The chunk wirtten is usually in the size of a disk block or one of some parameters (seen in stdio.h) like BUFSIZ or _DBUFSIZ. This is called a delayed write. It occurs when the kernel needs to reuse the buffer(s).
This is probably a bad suggestion... but... sync() queues a kernel dump of everything to disk that it has in cache - for all processes. It may have negative performance
implications, except in Linux where sync() is called by fflush() and fdatasync() as well.
Also I do not know if sync() exists for every flavor of unix. I do know that sync is the function called by the update daemon on systems I do know something about.
It sounds to me more like you have a management problem than a coding one. Get your manager to make the other coder add fflush() calls to his file I/O routine(s).
This means that the process doing the writing MUST cooperate to the extent that it calls fflush() on the stream after every fwrite / fputs call.
9 More Discussions You Might Find Interesting
1. Programming
Hi
I search an exemple of scheduling Feedback algorithm, or help about how to create one.
Thanks (0 Replies)
Discussion started by: messier79
0 Replies
2. Programming
Looking for an algorithm to compute the number of days between two given dates I came across a professor's C program located here: http://cr.yp.to/2001-275/struct1.c
I was wondering if anyone could tell me where the value 678882 in the line
int d = dateday - 678882;
comes from and also the... (1 Reply)
Discussion started by: williamf
1 Replies
3. Programming
what algorithm a FTP application uses i mean whn implemented in socket programming..if you could give a little decription (1 Reply)
Discussion started by: toughguy2handle
1 Replies
4. Shell Programming and Scripting
PID USERNAME SIZE RSS STATE PRI NICE TIME CPU PROCESS/NLWP
21444 tomusr 213M 61M sleep 29 10 1:20:46 0.1% java/43
21249 root 93M 44M sleep 29 10 1:07:19 0.2% java/56
is there anyway i can use a command to get the total of the SIZE? 306M (Derive from... (5 Replies)
Discussion started by: filthymonk
5 Replies
5. Programming
Hi guys , in my study book from which I re-learn C is task to generate all possible characters combination from numbers entered by the user. I know this algorithm must use combinatorics to calculate all permutations. Problem is how to implement algortihm.
// This program reads the four numbers... (0 Replies)
Discussion started by: solaris_user
0 Replies
6. Programming
Can you help to adjust the void dijkstra(int s) function to find a path from source to every node so that the minimum cost on that path is maximum.
Ex:
From 1 to 2 we have 1 - 3 - 4 - 2 , costs(2+3+4+5)
From 1 to 2 we have 1 - 5 - 6 - 2 , costs(3+3+4+5)
I need the algorithm to choose path 1... (4 Replies)
Discussion started by: ali2011
4 Replies
7. Shell Programming and Scripting
I have 250 files that have 16 columns each - all numbered as follows stat.1000, stat.1001, stat.1002, stat.1003....stat.1250.
I would like to join all 250 of them together tail by tail as follows. For example
stat.1000
a b c
d e f
stat.1001
g h i
j k l
So that my output... (2 Replies)
Discussion started by: kayak
2 Replies
8. Shell Programming and Scripting
I have a requirement of masking few specific fields in the UNIX file. The details are as following-
File is fixed length file with each record of 250 charater length.
2 fields needs to be masked – the positions are 21:30 and 110:120
The character by character making needs to be done which... (5 Replies)
Discussion started by: n78298
5 Replies
9. Shell Programming and Scripting
Redirecting the tail output fails when log rotation happens even though i have used -F. But when i tail and see the output on terminal this does not happen. Note i have also used & to execute this statement in background.
Suppose if i want to tail a file /opt/SAMPLE.txt and redirect its output... (1 Reply)
Discussion started by: CN1
1 Replies
TAIL(1) BSD General Commands Manual TAIL(1)
NAME
tail -- display the last part of a file
SYNOPSIS
tail [-F | -f | -r] [-q] [-b number | -c number | -n number] [file ...]
DESCRIPTION
The tail utility displays the contents of file or, by default, its standard input, to the standard output.
The display begins at a byte, line or 512-byte block location in the input. Numbers having a leading plus ('+') sign are relative to the
beginning of the input, for example, ``-c +2'' starts the display at the second byte of the input. Numbers having a leading minus ('-') sign
or no explicit sign are relative to the end of the input, for example, ``-n 2'' displays the last two lines of the input. The default start-
ing location is ``-n 10'', or the last 10 lines of the input.
The options are as follows:
-b number
The location is number 512-byte blocks.
-c number
The location is number bytes.
-f The -f option causes tail to not stop when end of file is reached, but rather to wait for additional data to be appended to the
input. The -f option is ignored if the standard input is a pipe, but not if it is a FIFO.
-F The -F option implies the -f option, but tail will also check to see if the file being followed has been renamed or rotated. The
file is closed and reopened when tail detects that the filename being read from has a new inode number. The -F option is ignored if
reading from standard input rather than a file.
-n number
The location is number lines.
-q Suppresses printing of headers when multiple files are being examined.
-r The -r option causes the input to be displayed in reverse order, by line. Additionally, this option changes the meaning of the -b,
-c and -n options. When the -r option is specified, these options specify the number of bytes, lines or 512-byte blocks to display,
instead of the bytes, lines or blocks from the beginning or end of the input from which to begin the display. The default for the -r
option is to display all of the input.
If more than a single file is specified, each file is preceded by a header consisting of the string ``==> XXX <=='' where XXX is the name of
the file unless -q flag is specified.
EXIT STATUS
The tail utility exits 0 on success, and >0 if an error occurs.
SEE ALSO
cat(1), head(1), sed(1)
STANDARDS
The tail utility is expected to be a superset of the IEEE Std 1003.2-1992 (``POSIX.2'') specification. In particular, the -F, -b and -r
options are extensions to that standard.
The historic command line syntax of tail is supported by this implementation. The only difference between this implementation and historic
versions of tail, once the command line syntax translation has been done, is that the -b, -c and -n options modify the -r option, i.e., ``-r
-c 4'' displays the last 4 characters of the last line of the input, while the historic tail (using the historic syntax ``-4cr'') would
ignore the -c option and display the last 4 lines of the input.
HISTORY
A tail command appeared in PWB UNIX.
BSD
June 29, 2006 BSD