01-14-2009
POSIX Message Queues
Quote:
Originally Posted by
pludi
ipcs and ipcrm, part of utils-linux(-ng)
yes, ipcs show the system v message queues but not the posix message queues.
if you mount the mqueue to the filesystem, you can see.
mkdir /dev/mqueue
mount -t mqueue none /dev/mqueue
10 More Discussions You Might Find Interesting
1. UNIX for Advanced & Expert Users
Hi,
I am working closly with unix message queues i have encountered the following -
after creating the Q and start working with it (pushing & pulling) i receive the following stange parameters on the q's -
STIME=no_entry
Qnum=0
CBYTES=4140
when this happens, the Q is disabled (meaning i... (3 Replies)
Discussion started by: kel
3 Replies
2. Programming
Hi there:
Thanks first. When I use a message queue amony severl processes, will I have to synchronize the queue? I don't think I would have to because a message queue is implemented in a link listed. Correct me If I am wrong... (0 Replies)
Discussion started by: yanhu
0 Replies
3. Programming
hi all,
I'm working on this problem for 2 days. Can somebody tell me that how to delete all message queues from the system ?
Since "ipcs -q" gives the list of all existing message queue, then there must be a system call and data stucture where from I can fetch the data about all existing... (2 Replies)
Discussion started by: v_rathor
2 Replies
4. Programming
Is there any way one can delete , say , a particular message from a message queue on system V? (2 Replies)
Discussion started by: satansfury
2 Replies
5. IP Networking
I am sending and retriving the message to the queue
the problem is
after retrieving the message can i see what is there in my message queue.
(actually in my application i am encountring some garbage value)
so i want to retieve this garbage value and also want to know its size
how... (0 Replies)
Discussion started by: ramneek
0 Replies
6. Programming
hi all...
ive been trying this program where i spawn 4 threads... and i am trying to use message queue to send msgs from 3 of the threads to the parent thread... but it doent seem to be working... ive almost pulled out my hair tryin to fix the prob :confused:
another wierd thing... (1 Reply)
Discussion started by: strider
1 Replies
7. Programming
Hello,
i need to write a message queue "chat server", that should work only localy.
Can anyone please help me with some ideas and peshaps code. I'm studying the UNIX IPC mechanisms right now. So far, i understand how it works but i still cannot get an idea how to write a chat programm...
... (2 Replies)
Discussion started by: etenv
2 Replies
8. Programming
Hii can anyone pls tell how to limit the max no of message in a posix message queue. I have made changes in proc/sys/fs/mqueue/msg_max
But still whenever i try to read the value of max. message in the queue using attr.mq_curmsgs (where struct mq_attr attr) its giving the default value as 10.... (0 Replies)
Discussion started by: mohit3884
0 Replies
9. Programming
Hi all,
I need help about message queues, i have a server-client program that communicates each other via msg queue, firstly server opens its msg queue and waits for msg then client opens server msg queue and its own msg queue(for receiving msg from server,clients sends msg to server msg... (7 Replies)
Discussion started by: SaTYR
7 Replies
10. Programming
Hello !!!!! I have a simple question but i can't find the answer anywhere hope to meet it here.
Why it is a bad idea to pass pointers through message queues ?
Most structs i see all of their char types are arrays... Is it becase having pointers means we could possibily send wrong bytes ?
For... (2 Replies)
Discussion started by: qlyine
2 Replies
IPCS(1) User Commands IPCS(1)
NAME
ipcs - show information on IPC facilities
SYNOPSIS
ipcs [options]
DESCRIPTION
ipcs shows information on the inter-process communication facilities for which the calling process has read access. By default it shows
information about all three resources: shared memory segments, message queues, and semaphore arrays.
OPTIONS
-i, --id id
Show full details on just the one resource element identified by id. This option needs to be combined with one of the three
resource options: -m, -q or -s.
-h, --help
Display help text and exit.
-V, --version
Display version information and exit.
Resource options
-m, --shmems
Write information about active shared memory segments.
-q, --queues
Write information about active message queues.
-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(2) and msgrcv(2) operations on message queues, the time of the last shmat(2) and shmdt(2) operations on shared mem-
ory, and the time of the last semop(2) 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
ipcmk(1), ipcrm(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 <https://www.kernel.org/pub/linux/utils/util-
linux/>.
util-linux July 2014 IPCS(1)