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.
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LEARN ABOUT OPENSOLARIS
msgget
msgget(2) System Calls msgget(2)
NAME
msgget - get message queue
SYNOPSIS
#include <sys/msg.h>
int msgget(key_t key, int msgflg);
DESCRIPTION
The msgget() argument returns the message queue identifier associated with key.
A message queue identifier and associated message queue and data structure (see Intro(2)) are created for key if one of the following are
true:
o key is IPC_PRIVATE.
o key does not already have a message queue identifier associated with it, and (msgflg&IPC_CREAT) is true.
On creation, the data structure associated with the new message queue identifier is initialized as follows:
o msg_perm.cuid, msg_perm.uid, msg_perm.cgid, and msg_perm.gid are set to the effective user ID and effective group ID, respec-
tively, of the calling process.
o The low-order 9 bits of msg_perm.mode are set to the low-order 9 bits of msgflg.
o msg_qnum, msg_lspid, msg_lrpid, msg_stime, and msg_rtime are set to 0.
o msg_ctime is set to the current time.
o msg_qbytes is set to the system limit. See NOTES.
RETURN VALUES
Upon successful completion, a non-negative integer representing a message queue identifier is returned. Otherwise, -1 is returned and errno
is set to indicate the error.
ERRORS
The msgget() function will fail if:
EACCES A message queue identifier exists for key, but operation permission (see Intro(2)) as specified by the low-order 9 bits of msgflg
would not be granted.
EEXIST A message queue identifier exists for key but (msgflg&IPC_CREAT) and (msgflg&IPC_EXCL) are both true.
ENOENT A message queue identifier does not exist for key and (msgflg&IPC_CREAT) is false.
ENOSPC A message queue identifier is to be created but the system-imposed limit on the maximum number of allowed message queue identi-
fiers system wide would be exceeded. See NOTES.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO
rctladm(1M), Intro(2), msgctl(2), msgrcv(2), msgsnd(2), setrctl(2), ftok(3C), attributes(5), standards(5)
NOTES
The system-defined limit used to initialize msg_qbytes is the minimum enforced value of the calling process's process.max-msg-qbytes
resource control.
The system-imposed limit on the number of message queue identifiers is maintained on a per-project basis using the project.max-msg-ids
resource control. The zone.max-msg-ids resource control restricts the total amount of message queue identifiers that can be allocated by a
zone.
See rctladm(1M) and setrctl(2) for information about using resource controls.
SunOS 5.11 14 Aug 2006 msgget(2)