03-11-2009
9 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
how can I lock my keyboard while I'm away from the computer without using lock command. What other commands gives me the option to lock keyboard device?
thanks (7 Replies)
Discussion started by: dianayun
7 Replies
2. HP-UX
Hello,there
here is my code about semphore, when calling it in the program,sometimes result in the deadlock of semphore, but I can not find it, anyone can point some bugs and give some suggestion?
#define BIGCOUNT 888 // initial value of process counter
#define SEM_POST_LIMIT 3 ... (0 Replies)
Discussion started by: Frank2004
0 Replies
3. UNIX for Advanced & Expert Users
Hi all,
I have a directory where some process is keeping incremental/new log files. I need to code a program which will periodically poll this directory and if it founds a new file arrived then copy that new file to some other specific directory.
We are OK with this polling approach. I just... (3 Replies)
Discussion started by: zing_foru
3 Replies
4. Shell Programming and Scripting
Hi,
I have some problem with following command.
$path='pwd'.”/pack”;
When I check the value in the variable path , it give the following output
/tmp/new /pack
The pwd will be /tmp/new
Now the problem is the spaces is added between pwd and the appended path.
I need the output like... (5 Replies)
Discussion started by: kalpeer
5 Replies
5. Solaris
Hello,
this is solaris 10 on SF v440,
I know below errors might go away if I put a new PS or put the original one back in socket but is there any other way to stop these errors from appearing in /var/adm/messages ? I do not want to put the failed PS1 in socket neither do we want to spend on... (5 Replies)
Discussion started by: upengan78
5 Replies
6. Red Hat
Hello all,
If anyone has time, I have a few questions:
How do I do the following in Linux. We are using Red Hat and Oracle Enterprise Linux, which is based on Red Hat too.
1. How to lock the account after a few (like 3) invalid password attempts?
2. How do you lock a screen after 30... (1 Reply)
Discussion started by: nstarz
1 Replies
7. Shell Programming and Scripting
Hi,
I am having multiple echo statements to print output
echo "$VAr"
echo "$lenght"
echo "$sum"
I get the output as
12
24
36
I need the output to be 12 24 36.
How do i arrive at this.
Thanks in advance (4 Replies)
Discussion started by: krashraj
4 Replies
8. UNIX for Advanced & Expert Users
Hi all,
I have to test some user priviliges. The goal is to be sure that an unauthorized user can't restart some modules (ssh, mysql etc...).
I'm trying to automate it with a shell script but in same cases I got the syslog broadcast message.
Is there any way to simply get a return code... (3 Replies)
Discussion started by: Dedalus
3 Replies
9. Shell Programming and Scripting
Hi I have a script which runs the isql command and takes the output in a xls file.
Is there a way to trim the spaces(leading and trailing) from all the values in the column of the xls sheet? (6 Replies)
Discussion started by: Sharma331
6 Replies
LEARN ABOUT OSF1
sem_wait
sem_wait(3) Library Functions Manual sem_wait(3)
NAME
sem_wait, sem_trywait - Performs (or conditionally performs) a semaphore lock (P1003.1b)
LIBRARY
Realtime Library (librt.so, librt.a)
SYNOPSIS
#include <semaphore.h>
int sem_wait (
sem_t *sem);
int sem_trywait (
sem_t *sem);
PARAMETERS
sem Specifies a pointer to the semaphore to be locked.
DESCRIPTION
The sem_wait function locks the semaphore referenced by sem by performing a semaphore lock operation on it. If the semaphore value is zero,
the sem_wait function blocks until it either locks the semaphore or is interrupted by a signal.
The sem_trywait function locks a semaphore only if the semaphore is currently not locked. If the semaphore value is zero, the sem_trywait
function returns without locking the semaphore.
These functions help ensure that the resource associated with the semaphore cannot be accessed by other processes. The semaphore remains
locked until the process unlocks it with a call to the sem_post function.
Use the sem_wait function instead of the sem_trywait function if the process should wait for access to the semaphore.
RETURN VALUES
If the sem_wait or sem_trywait function returns successfully, a value of 0 (zero) is returned and the function executes the semaphore lock
operation.
On an unsuccessful call, a value of -1 is returned and errno is set to indicate that an error occurred. The state of the semaphore remains
unchanged.
ERRORS
The sem_wait and sem_trywait functions fail under the following conditions:
[EAGAIN] The semaphore was already locked and cannot be locked by the sem_trywait operation (sem_trywait only).
[EINTR] A signal interrupted this function.
[EINVAL] The sem argument does not refer to a valid semaphore.
RELATED INFORMATION
Functions: sem_post(3)
Guide to Realtime Programming delim off
sem_wait(3)