examples/PIPS/opencmessagequeuelibraryex/engine/src/msgqsend.c

#include <errno.h>
#include <sys/msg.h>
#include <sys/sem.h>
#include <string.h>
#include "MsgQInternal.h"


/*******************************************************************************
* MsgQSend (qName, msg, nBytes, priority, timeout, err)
* Description:  Function for sending a message with internal copy
*********************************************************************************/

EXPORT_C int MsgQSend(ULONG qName, char* msg, ULONG nBytes, ULONG priority, int timeout, int* err)
{
        MSGQ_INFO* pMsgQInfo = NULL;

        struct {
                long mtype;
                char mtext[MAX_MSG_LEN];
        } message;

        /* structure used for semaphore post operation */
        struct sembuf op;
        
        /* init the  semop () structure which is used for wait and signal operations */
        op.sem_num = 0;
        op.sem_op = -1;
        op.sem_flg = SEM_UNDO;

        /* check parameters */
        if ((priority == MSG_PRI_NORMAL) || (priority == MSG_PRI_URGENT)) {
                if((pMsgQInfo = MsgQTableLookup(qName)) != NULL) {
                        if (pMsgQInfo->sendState == MSG_Q_READY) {
                                op.sem_flg = op.sem_flg | timeout;
                                if((semop(pMsgQInfo->semId, &op, 1)) == OK) {
                                        pMsgQInfo->numMsgs++;
                                        if(pMsgQInfo->maxNumMsgs < pMsgQInfo->numMsgs)          
                                        pMsgQInfo->maxNumMsgs = pMsgQInfo->numMsgs;

                                        message.mtype = 1;
                                        bcopy(msg, message.mtext, nBytes);
                                        message.mtext[nBytes] = '\0';

                                        if(msgsnd (pMsgQInfo->qId, &message, (size_t)nBytes+4, timeout) == OK) {
                                                *err = OK;
                                                /* After successfull send, unlock the message queue by using post operation on semaphore.*/
                                                op.sem_op = 1;
                                                semop(pMsgQInfo->semId, &op, 1);
                                                return (OK);
                                        }
                                        else {
                                                *err = errno;
                                                pMsgQInfo->numMsgs--;
                                                op.sem_op = 1;
                                                semop(pMsgQInfo->semId, &op, 1);
                                        }
                                }
                                else
                                        *err = errno;
                        }
                        else
                                *err = KMsgQLibQFlushErr;
                }
                else
                        *err = KMsgQLibQIdErr;
        }
        else
                *err = KMsgQLibParamErr;

        return(ERROR);
}

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