10 More Discussions You Might Find Interesting
1. 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
2. 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
3. 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
4. Programming
Hi!!
This code works if I don't remove the message queue.
In A.c I create 3 processes that send a message in a message queue.
in B.c other 3 processes receive 1 message for each (the messages sent from A), change the value of "dato" and put again the message in the queue.
The processes in A.c... (0 Replies)
Discussion started by: Sentinella
0 Replies
5. 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
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
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
8. 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
9. UNIX for Dummies Questions & Answers
I have a problem with running jobs out of cron on Solaris 8.
Initially when one of the users on the box (other than root) attempted to save the crontab after modification by using "crontab -e", the message "Crontab: cannot open the crontab file in the crontab directory" was given.
I then... (7 Replies)
Discussion started by: mattd
7 Replies
10. 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
mq_close(3) Library Functions Manual mq_close(3)
NAME
mq_close - Closes a message queue (P1003.1b)
LIBRARY
Realtime Library (librt.so, librt.a)
SYNOPSIS
#include <mqueue.h>
int mq_close (
mqd_t mqdes);
PARAMETERS
mqdes Specifies a message queue descriptor.
DESCRIPTION
The mq_close function closes a message queue. This function removes the association between the message queue descriptor, mqdes, and its
open message queue description. When all message queue descriptors associated with an open message queue description have been closed, the
associated open message queue description is removed. The message associated with the message queue will then be deleted if mq_unlink was
already called, or is called after all processes have closed the queue.
RETURN VALUES
On successful completion, the function returns the value 0 (zero); otherwise, the function returns the value -1 and sets errno to indicate
the error.
ERRORS
The mq_close function fails under the following conditions:
[EBADF] The mqdes argument is an invalid message queue descriptor.
[EFAULT] An internal virtual memory error occurred.
RELATED INFORMATION
Functions: mq_open(3), mq_unlink(3)
Guide to Realtime Programming delim off
mq_close(3)