09-14-2008
10 More Discussions You Might Find Interesting
1. Programming
Dear Reader,
I'm in a multiprocess environment working with shared mem and semaphores as mutex.. The problem is -- If one of the process hooked up with the semaphore and accessing the shared mem, terminates abruptly ( or got killed ), other process which are in want of the semaphore are... (1 Reply)
Discussion started by: joseph_shibu
1 Replies
2. UNIX for Dummies Questions & Answers
Hi all,
I am using HP 10.20 on A 9000/785. My question is:
If I am the only person logged in as root at the moment, how many "semaphore proccesses" should I have?? Is it only one, or it is relevant to other system proccesses?
Here is what I get listing the current semaphores
# ipcs -sp... (1 Reply)
Discussion started by: guest100
1 Replies
3. Programming
Hi there,
Could someone please confirm which POSIX semaphore routines should be used for a multiprocess (and not multithreaded) environment?
sys/sem.h definitely works. but the routines, semget, semctl, semop are pretty unwieldy. So, I am looking for an easier way out.
From the man pages... (2 Replies)
Discussion started by: qntmteleporter
2 Replies
4. Shell Programming and Scripting
Hi Friends,
If i execute this command it comes back with 300 lines:
ipcs|grep cerebrus >>> i would like to clear the semaphores but ipcrm can remove one id at a time. is there a quicker way of removing semaphores maybe using awk?
Regards, (1 Reply)
Discussion started by: kekanap
1 Replies
5. Programming
been searching around on how to use an up and down function with semaphores but i can't find an example. i looked into using: "semop" but i have no idea how to use it. I have been able to declared the semaphores using semget and initializing them using semctl. (7 Replies)
Discussion started by: ddx08
7 Replies
6. UNIX for Advanced & Expert Users
Hello, first of all I apologize if this thread is not in the correct section of this forum, but this one just seemed the most appropriate.
The question I have does not concern Unix specifically, it applies to virtually any OS, however it is in Unix where I learned about this problem.
So, the... (8 Replies)
Discussion started by: Watto86
8 Replies
7. UNIX for Dummies Questions & Answers
I am having problem with semaphores. I am trying to protect line where process prints so that every process with print in proper order.This is the code..
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/types.h>
union... (3 Replies)
Discussion started by: joker40
3 Replies
8. Programming
Hello Everybody,
I am building a server. this server contains some data. Clients may modify this data or read this data.
If a client is reading the data and at the same time another client is modifying the data then at this case the reading client may read some false data (some old mixed with... (1 Reply)
Discussion started by: Omar_Mokhtar
1 Replies
9. Solaris
Hi,
Can somebody please explain me what semaphores are? there purpose? and there effects?
Thanks in advance:) (0 Replies)
Discussion started by: Laxxi
0 Replies
10. Programming
hallo!
if there are many processes running and I initialize the semaphore like this:
my_sem = sem_open(SEM_NAME, O_CREAT | O_RDWR,
S_IRUSR | S_IWUSR, 10);
(the last argument is 10)
and then i use
sem_wait(my_sem);
sleep(5);
sem_post;
Will 10 processes be able to access the... (0 Replies)
Discussion started by: whatevernever
0 Replies
IPCS(1) User Commands IPCS(1)
NAME
ipcs - provide information on IPC facilities
SYNOPSIS
ipcs [resource-option] [output-format]
ipcs [resource-option] -i id
DESCRIPTION
ipcs provides information on the inter-process communication facilities for which the calling process has read access.
OPTIONS
-i, --id id
Print details only on the resource identified by id.
-h, --help
Display a help text and exit.
-V, --version
Display version information and exit.
Resource options
-q, --queues
Write information about active message queues.
-m, --shmems
Write information about active shared memory segments.
-s, --semaphores
Write information about active semaphore sets.
-a, --all
Write information about all three resources (default).
Output formats
Of these options only one takes effect: the last one specified.
-c, --creator
Show creator and owner.
-l, --limits
Show resource limits.
-p, --pid
Show PIDs of creator and last operator.
-t, --time
Write time information. The time of the last control operation that changed the access permissions for all facilities, the time of
the last msgsnd() and msgrcv() operations on message queues, the time of the last shmat() and shmdt() operations on shared memory,
and the time of the last semop() operation on semaphores.
-u, --summary
Show status summary.
Representation
These affect only the -l (--limits) option.
-b, --bytes
Print sizes in bytes.
--human
Print sizes in human-readable format.
SEE ALSO
ipcrm(1), ipcmk(1), msgrcv(2), msgsnd(2), semget(2), semop(2), shmat(2), shmdt(2), shmget(2)
CONFORMING TO
The Linux ipcs utility is not fully compatible to the POSIX ipcs utility. The Linux version does not support the POSIX -a, -b and -o
options, but does support the -l and -u options not defined by POSIX. A portable application shall not use the -a, -b, -o, -l, and -u
options.
AUTHOR
Krishna Balasubramanian <balasub@cis.ohio-state.edu>
AVAILABILITY
The ipcs command is part of the util-linux package and is available from Linux Kernel Archive <ftp://ftp.kernel.org/pub/linux/utils/util-
linux/>.
util-linux January 2013 IPCS(1)