Sponsored Content
Top Forums UNIX for Advanced & Expert Users Problem while writing to a file...? Post 302290031 by Corona688 on Saturday 21st of February 2009 11:52:18 AM
Old 02-21-2009
Like jim says, read your system documentation on fcntl(). You can do advisory locking, in which you:
  • Open the file
  • Call ioctl(fileno, F_GETLK, &lockdata) where lockdata is a properly filled 'struct flock' structure, details on which are in the fcntl documentation.
  • If the lock succeeds, you have the file. If you don't, you don't.
  • If you locked the file, call ioctl again with F_SETLK to release your lock.
 

10 More Discussions You Might Find Interesting

1. HP-UX

Problem in HP-Unix while writing into socket

Our system is having a server and multiple clients. We are monitoring the client FDs using select() system call in HP-UX. After establishing connection-using socket with the remote client, before start sending the data we are checking the status of socket using select( ) call. For first 16... (0 Replies)
Discussion started by: AshokG
0 Replies

2. UNIX for Dummies Questions & Answers

Problem with writing a program

Hi guys I'm having trouble with trying to create a script which calculates the grade of a student and the marks out of 300. The grades are: 0-49% fail 50-59% pass 60-69% credit pass 70-79% distinction 80-100% high distinction less than 0 or greater than 100 displays error message. My... (1 Reply)
Discussion started by: CompNoob
1 Replies

3. Programming

very bizzare file writing problem

I'm trying to write a function which opens a file pointer and writes one of the function parameters into the file, however for some reason Im getting a core dump error. The code is as below void WriteToFile(char *file_name, char *data) { FILE *fptr; /*disk_name_size is a... (10 Replies)
Discussion started by: JamesGoh
10 Replies

4. UNIX for Dummies Questions & Answers

Problem writing file path to txt file

if test -z "$1" then echo "you must give a filename or filepath" else path=`dirname $1` f_name =`basename $1` if path="." then path=`pwd` fi fi cat $f_name $path >> index.txt The only problem I am encountering with this is writing $path to index.txt Keeps going gaga: cat:... (1 Reply)
Discussion started by: Vintage_hegoog
1 Replies

5. Shell Programming and Scripting

Script writing problem

Self professed idot looking for help LOL Hi all, I am new to Unix and I have to write a shell script that will check to see if a file exist and then create it if it does not. The file I need to search for is titled "A1. dat" and here is my feeble attempt at creating the script: #!/bin/bash... (2 Replies)
Discussion started by: Tinablue
2 Replies

6. Shell Programming and Scripting

Problem in writing the data to a file in one row

Hi All I am reading data from the database and writing to temporary file in the below format. 1=XP|external_component|com.adp.meetingalertemail.processing.MeetingAlertEmail|EMAILALERTPUSH|32|4#XP |classpath|/usr/home/dfusr/lib/xalan.jar: /usr/home/dfusr/lib/xerces.jar: ... (2 Replies)
Discussion started by: rajeshorpu
2 Replies

7. Shell Programming and Scripting

Problem writing to different files

Hello: I have the following code: ---------------------------------- open (OUTPUT_FILE, ">>/usr/users/rovolis/PREPAID/CC/TCG/PP.$cyear$cmonth$cday.txt")||die "$!"; 82 open (OUTPUT_FILE2, ">>/usr/users/rovolis/PREPAID/CC/TCG/PR.$cyear$cmonth$cday.txt")||die "$!"; 83 # ... (0 Replies)
Discussion started by: chriss_58
0 Replies

8. Shell Programming and Scripting

Problem with writing into a file through shell script

Hi all, I have a shell script which I use to login to the server from the client and then from the server I run a bunch of other scripts to complete my task. I am having problems with the script below- #!/bin/bash while read line do connections=`echo $line | cut -d " " -f 1` period=`echo... (3 Replies)
Discussion started by: joydeep4u
3 Replies

9. Shell Programming and Scripting

Problem writing a search script

I trying to write a script in bash that take a list of users in “fileA” and searches another list user in “fileB” if the user does not exist in “file B” write the user to another file “file C”. Please note “fileA” and “fileB” contains over 1000 users Basically “fileA” “fileB” ... (2 Replies)
Discussion started by: hassan1
2 Replies

10. Shell Programming and Scripting

Problem with writing to output - awk, echo

Hello all, I wrote this command line for some calculation on my given input files based on another input file which is a txt file. while read BAM REGION; do samtools view $BAM $REGION | awk '{if ($2==0) print $0}' | wc -l >>log.txt; echo "$REGION"; done >> log.txt <regions.txt It takes... (4 Replies)
Discussion started by: @man
4 Replies
VOP_ADVLOCK(9)						   BSD Kernel Developer's Manual					    VOP_ADVLOCK(9)

NAME
VOP_ADVLOCK -- advisory record locking SYNOPSIS
#include <sys/param.h> #include <sys/vnode.h> #include <sys/fcntl.h> #include <sys/lockf.h> int VOP_ADVLOCK(struct vnode *vp, caddr_t id, int op, struct flock *fl, int flags); DESCRIPTION
The arguments are: vp The vnode being manipulated. id The id token which is changing the lock. op The operation to perform (see fcntl(2)). fl Description of the lock. flags One of more of the following: F_RDLCK Shared or read lock. F_UNLCK Unlock. F_WRLCK Exclusive or write lock. F_WAIT Wait until lock is granted. F_FLOCK Use flock(2) semantics for lock. F_POSIX Use POSIX semantics for lock. This entry point manipulates advisory record locks on the file. Most file systems delegate the work for this call to lf_advlock(). RETURN VALUES
Zero is returned on success, otherwise an error is returned. SEE ALSO
fcntl(2), flock(2), vnode(9) AUTHORS
This manual page was written by Doug Rabson. BSD
June 30, 1999 BSD
All times are GMT -4. The time now is 01:07 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy