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Full Discussion: Unix message Queue
Top Forums UNIX for Advanced & Expert Users Unix message Queue Post 38919 by Perderabo on Wednesday 30th of July 2003 11:12:50 AM
Old 07-30-2003
Hmmm....you do have a point. I was getting CBYTES mixed up with QBYTES.

I agree, for the most part, QNUM = 0 and CBYTES != 0 is not consistent. But I can think of one exception where it might make sense. When you do your msgsnd, you are setting msgflg to zero. That means that IPC_NOWAIT is turned off. The msgsnd system call checks to see if this message would exceed some limits. This includes a check of the message queue you are using as well as some system wide limits. If a msgsnd would exceed a limit and it did not set IPC_NOWAIT, the msgsnd system call will suspend until it is safe to send the message. I don't know what state the message queue is in during this suspension. It could well be that CBYTES has been increased but QNUM has not yet been incremented.

This would explain why it works for a few hours and then locks up. Reproduce the error and then run "ipcs -qa" and compare the total messages queue resources in use against your kernel parameters. If this is the problem, you will need to increase the kernel parameters. Or you may have a message queue leak somewhere.

That is my only idea. If it's not that, I would next suspect a broken kernel. You might check for any appropiate patches.
 

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LEARN ABOUT OPENSOLARIS

sip_add_branchid_to_via

sip_add_branchid_to_via(3SIP)			   Session Initiation Protocol Library Functions		     sip_add_branchid_to_via(3SIP)

NAME

       sip_add_branchid_to_via - add a branch parameter to the topmost VIA header in the SIP message

SYNOPSIS

       cc [ flag ... ] file ... -lsip [ library ... ]
       #include <sip.h>

       int sip_add_branchid_to_via(sip_msg_t sip_msg, char *branchid);

DESCRIPTION

       The  sip_add_branchid_to_via() function adds a branch param to the topmost VIA header in the SIP message sip_msg. Note that a new header is
       created as a result of adding the branch parameter and the old header is marked deleted. Applications with multiple threads working on  the
       same VIA header need to take note of this.

RETURN VALUES

       These functions return 0 on success and the appropriate error value on failure.

ERRORS

       On failure, functions that return an error value may return one of the following:

       EINVAL	 Mandatory parameters are not provided or are NULL.

		 For sip_add_branchid_to_via(), the topmost VIA header already has a branch param or the SIP message does not have a VIA header.

       EPERM	 The message cannot be modified.

       ENOMEM	 There is an error allocating memory for creating headers/parameters.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       libsip(3LIB)

SunOS 5.11							    25 Jan 2007 				     sip_add_branchid_to_via(3SIP)
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