Sponsored Content
Full Discussion: Message queues
Top Forums Programming Message queues Post 71635 by blowtorch on Friday 13th of May 2005 12:27:48 AM
Old 05-13-2005
You would be best off having two programs, but not in the same way that you have created. Have one program that is the "server". This will create the message queue when it starts up, and destroy the queue when it shuts down. The second program will be the client program that will just connect to the message queue (no IPC_CREAT).

The client program will put messages with a type flag set to some unique value ( using the program's pid would be a good idea ); while msgrcv will be done with type set to the the unique value, but with the flag set to MSG_EXCEPT - this will pick up messages with any type that is not the value set as msgtyp in the msgrcv call.

A single program will probably complicate things unnecessarily.
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

message queues

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)
Discussion started by: sukaam
2 Replies

2. Solaris

rogue message queues solaris 9

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)
Discussion started by: MizzGail
2 Replies

3. Linux

maximun number of message queues

how to check the maximun number of message queues in current linux enviornment? is there any command ? (4 Replies)
Discussion started by: princelinux
4 Replies

4. Programming

shared memory and message queues

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)
Discussion started by: rvan
2 Replies

5. UNIX for Advanced & Expert Users

UNIX Message Queues vs. Sockets

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)
Discussion started by: zen29sky
2 Replies

6. UNIX for Advanced & Expert Users

message queues

#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)
Discussion started by: tolkki
1 Replies

7. UNIX for Dummies Questions & Answers

message queues

can any body provide a tutorial that explains the concept of message queues in UNIX in great detail (1 Reply)
Discussion started by: asalman.qazi
1 Replies

8. Programming

Persisting message queues to disk

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

9. Shell Programming and Scripting

Cleaning Message Queues

i have an application installed on AIX 5.3 and i have made a script that shutdown a proccesses that exceeded 10000kb of memory usage but i have a problem with cleaning the message queues of these proccesses after shutting them down. Is there any way to clean the message queues for this particular... (8 Replies)
Discussion started by: Portabello
8 Replies

10. UNIX for Advanced & Expert Users

Performance calculation for Message Queues

i have a program(C++ Code) that sends/receives information through queue's (Uses MQ) Is there any UNIX/LINUX tool that calculates the load and performance time for the same. If not how do i design the program that calculates the performance time. i know that time.h can be used but it gives... (2 Replies)
Discussion started by: vkca
2 Replies
msg.h(3HEAD)							      Headers							      msg.h(3HEAD)

NAME
msg.h, msg - message queue structures SYNOPSIS
#include <sys/msg.h> DESCRIPTION
The <sys/msg.h> header defines the following data types through typedef: msgqnum_t used for the number of messages in the message queue msglen_t used for the number of bytes allowed in the message queue These types are unsigned integer types that are able to store values at least as large as a type unsigned short. The <sys/msg.h> header defines the following constant as a message operation flag: MSG_NOERROR no error if big message The msqid_ds structure contains the following members: struct ipc_perm msg_perm Operation permission structure. msgqnum_t msg_qnum Number of messages currently on queue. msglen_t msg_qbytes Maximum number of bytes allowed on queue. pid_t msg_lspid Process ID of last msgsnd(2). pid_t msg_lrpid Process ID of last msgrcv(2). time_t msg_stime Time of last msgsnd(). time_t msg_rtime Time of last msgrcv(). time_t msg_ctime Time of last change. The pid_t, time_t, key_t, size_t, and ssize_t types are defined as described in <sys/types.h>. See types(3HEAD). ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ SEE ALSO
msgctl(2), msgget(2), msgrcv(2), msgsnd(2), ipc.h(3HEAD), types.h(3HEAD), attributes(5), standards(5) SunOS 5.10 10 Sep 2004 msg.h(3HEAD)
All times are GMT -4. The time now is 11:41 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy