message sending failed : Error[22 ] invalid argument .....but each and every argument is correct.using posix standard system commands...

Way too terse. What are you doing (post exact commands) and in what environment?

PROBLEM : It is in PostToConfigMsgQueue()
Environment : Fedora core 4

------------------------------------------Following is the code snippet----------------------

/* Message Queue User defined data structure */
typedef struct _MsgQData
{
ModuleId eModuleId; /**************Enum **************/
CommandId eCommandId;/**************Enum **************/
void *pMsg;
} MsgQData;



/***************************This is invoked by main module*********************/
int32 ConfigInit()
{
int32 iRetVal = SUCCESS;
int32 iMsgflg = IPC_CREAT|0666;
key_t key2;
int8 *pchConfig = "Config Thread is called";
LogTraceMsg(CFG, "Entered into ConfigInit() function\n");
LogDebugMsg(CFG,"Initializing Config Module \n");
/********************* Creating Config Message queue ************************/
iMsgId2 = msgget(key2 , iMsgflg);
if(-1 == iMsgId2)
{
LogErrorMsg (CFG,"Message queue creation of Config module failed\n");
iRetVal = FAILURE;
LogTraceMsg(CFG, "Exiting from ConfigInit() function\n");
return iRetVal;
}
/*****************************Creating thread for Config module**********************/
iRetVal= pthread_create(&tid2 , NULL , ConfigThread , (void*)pchConfig );
if(0 != iRetVal)
{
LogErrorMsg (CFG,"thread creation of Config module failed\n");
iRetVal = FAILURE;
LogTraceMsg(CFG, "Exiting from ConfigInit() function\n");
return iRetVal;
}
LogTraceMsg(CFG, "Exiting from ConfigInit() function\n");
return SUCCESS;
}/* End of ConfigInit() */

/******************************************************************************
* Function Name : ConfigThread()
* Return Values : NULL
* Global variables : sCfgQData,iMsgId2
* Description : This function posts INIT_SUCCESS message to PSM
* and also wait for messages at its own Msg Queue.
******************************************************************************/

void* ConfigThread(void *ptr)
{
MsgQData sCfgQData;
int8 *pchMsg;
pchMsg = (int8 *)ptr;
LogTraceMsg(CFG, "Entered into ConfigThread() function\n");
printf(" %s \n\n",pchMsg);
/*****************This posting works***********************************/
PostToPsmMsgQueue(CFG,INIT_SUCCESS,NULL);
while(1)
{
msgrcv(iMsgId2,(void *)&sCfgQData,sizeof(MsgQData),0,MSG_NOERROR);
if(UNINIT == sCfgQData.eCommandId)
{
LogDebugMsg(CFG," UNINIT received in the Config \n");
break;
}

}/* End of while(1) */
LogTraceMsg(CFG, "Exiting from ConfigThread() function\n");
ConfigUnInit();
return NULL;
}/* End of void* ConfigThread(void *ptr) */

/******************************************************************************
* Function Name : PostToConfigMsgQueue()
* Return Values : iRetVal
* Global variables : sCfgMsgQData,iMsgId2
* Description : This function is Posting messages to CFG message queue.
******************************************************************************/
/******************************This is invoked by other module files******************/
int32 PostToConfigMsgQueue(IN ModuleId eSndModuleId,
IN CommandId eSndCommandId,
void* pSndMsg)
{
int32 iRetVal = SUCCESS;
MsgQData sCfgMsgQData;
sCfgMsgQData.eModuleId = eSndModuleId;
sCfgMsgQData.eCommandId = eSndCommandId;
//sCfgMsgQData.pMsg = pSndMsg;
sCfgMsgQData.pMsg = NULL;

LogTraceMsg(CFG, "Entered into PostToConfigMsgQueue() function\n");
/***********************Here this system call fails with saying invalid argument Error[22] ********************************************************************************************/
iRetVal = msgsnd(iMsgId2,(void *)&sCfgMsgQData,sizeof(MsgQData),MSG_NOERROR);
if (-1 == iRetVal)
{
fprintf(stderr, "msgsnd failed in config with error:[%d],[%s]\n",errno,sys_errlist[errno]);
exit(0);
}
iRetVal = SUCCESS;
LogTraceMsg(CFG, "Exiting from PostToConfigMsgQueue() function\n");
return iRetVal;
}/* End of PostToConfigMsgQueue() */

/******************************************************************************
* Function Name : ConfigUnInit()
* Return Values : None
* Global variables : iMsgId2
* Description : This function un-initializes Config module.
******************************************************************************/

void ConfigUnInit(void)
{
struct msqid_ds *pBuf;
LogTraceMsg(CFG, "Entered into ConfigUnInit() function\n");
msgctl(iMsgId2,IPC_RMID,pBuf);
LogTraceMsg(CFG, "Exiting from ConfigUnInit() function\n");
pthread_exit(NULL);
return;
}/* End of ConfigUnInit() */