07-30-2003
Hi,
Thanks for your replay.
I'll try to be more clear -
1. i have created the Q as follow:
'o_qid = msgget(IPC_PRIVATE,IPC_CREAT|0777|IPC_EXCL|S_IRUSR|S_IWUSR);'
And worked with the Q as follow:
'msgsnd( qid, (void*)(&eventDataBuffer), MessageSize, 0) '
'qbytesread=msgrcv(qid, (void*)pMessage, max_msgsize, -MSGTYPE_MAX_APP_RANGE, 0)'
2. The Q has functioned OK for about an hour, where data was surely sent & received.
3. On a certain point, i could not send, nor receive from the Q.
The parameters on the Q where:
Qnum=0 (The number of messages currently outstanding on the
associated message queue.)
CBYTES= ~4k (The number of bytes in messages currently outstanding on the associated message queue.)
This is what i do not understand. How come there are no messages, and the Q inform me that the data size is greater than 0?
I hope i made more clear.
Thanks Again.
10 More Discussions You Might Find Interesting
1. 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
2. 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
3. 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
4. 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
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
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
7. 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
8. 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
9. Shell Programming and Scripting
Hi,
I need to move the XML files from the UNIX to the message queue. Please help me out to write the code..
Thanks,
Mohana Krishnan (0 Replies)
Discussion started by: krishnan_6015@y
0 Replies
10. Programming
in a single main() function,so need signal handling. Use Posix Message Queue IPC mechanism , can ignore the priority and other linked list message,to implement the scenario:
client:Knock Knock
server:who's there
client: Eric
Server:Eric,Welcome.
client:exit
all process terminated
... (1 Reply)
Discussion started by: ouou
1 Replies
LEARN ABOUT OPENSOLARIS
msg.h
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 5.11 10 Sep 2004 msg.h(3HEAD)