i think i am going to use it, but do you have any idea how to use that to clean the message queues for a particular processes ?
generally speaking, not in my case only
Only if you know the uid of the process you want to kill...as it is easy to identify the message queues associated with a userid and command is...
Hi all,
I've been trying for hours to figure out how to turn my 2-program (one to send and one to receive) "chat system" using message queues, into a single program where each concurrent component (entity) will both send and receive messages. PLEASE give me a hand with this, I'm starting to... (9 Replies)
let 3 processes a, b and c are sharing msgs using msg queues.process 'a' sending msg to 'c' and in turn 'c' send sthat msg to 'b'.if something happens to c how can 'a' and 'b' know that 'c' is not available?????? (2 Replies)
We have message queues created from our ERP system to our tax system via an application api written by the ERP software vendor.
Occasionally when a user does not gracefully exit the ERP application, the message queue hangs. After a few months, this becomes a problem as the queues are all used... (2 Replies)
Hi,
According to my understanding..
When message queues are used, when a process post a message in the queue and if another process reads it from the queue then the queue will be empty unlike shared memory where n number of processess can access the shared memory and still the contents remain... (2 Replies)
If I use sockets for IPC, and can easily distribute my applications.
UNIX Message Queues are local to the processor.
As I understand it, Message Queues still incur system call overhead, just like socket calls.
What advantage does a UNIX Message Queue provide versus a TCP or UDP Socket,... (2 Replies)
Hi,
Am supposed to use message queues to send and receive messages between the processes. when i was working on that i realised that the message qid and the message queue related data should be maintained in a shared memory so that it can be accessed by all the processes. Could anybody refer... (10 Replies)
#include <sys/ipc.h>
#include <sys/msg.h>
int main()
{
int qid;
int t;
struct msgbuf mesg;
qid=msgget(IPC_PRIVATE,IPC_CREAT);
mesg.mtype=1L;
mesg.mtext=1;
t=msgsnd(qid,&mesg,1,0);
printf("%d",t);
}
the program prints -1 as the result of msgsnd ,which means that msgsnd doesn't... (1 Reply)
Hi,
I have searched the forums and could not find a relavant thread discussing my use case, hence the new post.
Basically am trying to pass on work to dummy worker instances from controller which will pass on work to workers (client)
To make use of host capacity, am planning to serialize... (2 Replies)
Discussion started by: matrixmadhan
2 Replies
LEARN ABOUT OSX
ipcs
IPCS(1) BSD General Commands Manual IPCS(1)NAME
ipcs -- report System V interprocess communication facilities status
SYNOPSIS
ipcs [-abcMmopQqSsTt]
DESCRIPTION
The ipcs utility provides information on System V interprocess communication (IPC) facilities on the system.
The options are as follows:
-a Show the maximum amount of information possible when displaying active semaphores, message queues, and shared memory segments. (This
is shorthand for specifying the -b, -c, -o, -p, and -t options.)
-b Show the maximum allowed sizes for active semaphores, message queues, and shared memory segments. The ``maximum allowed size'' is
the maximum number of bytes in a message on a message queue, the size of a shared memory segment, or the number of semaphores in a
set of semaphores.
-c Show the creator's name and group for active semaphores, message queues, and shared memory segments.
-M Display system information about shared memory.
-m Display information about active shared memory segments.
-o Show outstanding usage for active message queues, and shared memory segments. The ``outstanding usage'' is the number of messages in
a message queue, or the number of processes attached to a shared memory segment.
-p Show the process ID information for active semaphores, message queues, and shared memory segments. The ``process ID information'' is
the last process to send a message to or receive a message from a message queue, the process that created a semaphore, or the last
process to attach or detach a shared memory segment.
-Q Display system information about messages queues.
-q Display information about active message queues.
-S Display system information about semaphores.
-s Display information about active semaphores.
-T Display system information about shared memory, message queues and semaphores.
-t Show access times for active semaphores, message queues, and shared memory segments. The access times is the time of the last con-
trol operation on an IPC object, the last send or receive of a message, the last attach or detach of a shared memory segment, or the
last operation on a semaphore.
If none of the -M, -m, -Q, -q, -S, or -s options are specified, information about all active IPC facilities is listed.
RESTRICTIONS
System data structures may change while ipcs is running; the output of ipcs is not guaranteed to be consistent.
BUGS
This manual page is woefully incomplete, because it does not at all attempt to explain the information printed by ipcs.
SEE ALSO ipcrm(1)AUTHORS
Thorsten Lockert <tholo@sigmasoft.com>
BSD June 18, 1994 BSD