Message Queue - Client Code

MsgQueClient.c

#include<stdio.h>
#include<mqueue.h>
#include<string.h>
#include<fcntl.h>
#include<sys/stat.h>
#include<unistd.h>

#define MESSAGE_PRIO 0

mqd_t MQDes;
int ret;	
char Message[100];	
char MQName[10] = "/MQServer";
ssize_t NoOfBytesRx;
struct mq_attr MQStat;
int quit;
struct sigevent SIGNAL;

static void RxMessage(union sigval sv)
{
	ret = mq_getattr(MQDes, &MQStat);
	if(ret == -1)
	{
		perror("mq_getattr");
		return;
	}
	printf("On Entering MQStat.mq_curmsgs: %ld\n",MQStat.mq_curmsgs);
	NoOfBytesRx = mq_receive(MQDes, Message, (MQStat.mq_msgsize) , MESSAGE_PRIO);
	
	if(NoOfBytesRx == -1)
	{
		perror("mq_receive");
		return;
	}
	
	printf("%s",Message);	
	
		
	if(strcasecmp(Message, "OVER") == 0)
	{
		printf("\n");
		quit = 1;
	}
	else
	{
	ret = mq_getattr(MQDes, &MQStat);
	if(ret == -1)
	{
		perror("mq_getattr");
		return;
	}
		printf("On Exiting MQStat.mq_curmsgs: %ld\n",MQStat.mq_curmsgs);
		ret = mq_notify(MQDes, &SIGNAL);
		if(ret == -1)
		{
			perror("mq_notify");
			return;
		}
	}
	
	return;
}

int main(void)
{		
	MQDes = mq_open(MQName, O_RDONLY);
	if(MQDes == -1)
	{
		perror("mq_open");
		return -1;
	}
	
	ret = mq_getattr(MQDes, &MQStat);
	if(ret == -1)
	{
		perror("mq_getattr");
		return -1;
	}
	printf("MQ_MAXMSG:%ld\n",MQStat.mq_maxmsg);
	printf("MQ_MSGSIZE:%ld\n",MQStat.mq_msgsize);
	
	printf("These are the messages from the server:\n");
	
	SIGNAL.sigev_notify = SIGEV_THREAD;
	SIGNAL.sigev_notify_function = RxMessage;
	SIGNAL.sigev_notify_attributes = NULL;
	
	#ifdef NOTIFY
	ret = mq_notify(MQDes, &SIGNAL);
	if(ret == -1)
	{
		perror("mq_notify");
		return -1;
	}
	#endif
	
	do
	{			
	#ifndef NOTIFY
	NoOfBytesRx = mq_receive(MQDes, Message, (MQStat.mq_msgsize) , MESSAGE_PRIO);
	
	if(NoOfBytesRx == -1)
	{
		perror("mq_receive");
		return -1;
	}
	
	printf("%s",Message);
	
	if(strcasecmp(Message, "OVER") == 0)
	{
		printf("\n");
		quit = 1;
	}
	#endif
	
	}while(quit!=1);
	
	return 0;
}