shrdmemcon.c

word count information using message queues

#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<unistd.h>
#include<sys/shm.h>
#include<sys/sem.h>
#include<sys/ipc.h>
#include<string.h>

#define SIZE 1000

union semun 
	{
	int val;
	struct semid_ds *buf;
	ushort *array;
	};
int main()
{
printf("sa\n");

char *msg,*data;
key_t uniqkey;
uniqkey=ftok(".",'J');
int shmid,semid;
shmid=shmget(uniqkey,SIZE,IPC_CREAT|0644);
if(shmid==-1)
	{
	printf("error in creating shared memory \n");
	}
msg=shmat(shmid,(void *)0,0);

semid=semget(uniqkey,2,0);
if(semid==-1)
	{
	printf("error in making semaphore \n");
	}
struct sembuf acquire={0,-1,SEM_UNDO};
struct sembuf release={0, 1,SEM_UNDO};



int ch=0;

while(ch<5)
{

acquire.sem_num=1;
if(semop(semid,&acquire,1)==-1)
	{
	printf("error in acquiring \n");
	}

printf("msg has %s \n",msg);		//using shared memory

release.sem_num=0;
if(semop(semid,&release,1)==-1)
	{
	printf("error in releasing \n");
	}
//sleep(7);
ch++;
}

sleep(3);
if(shmdt(msg)== -1)
	{
	printf("error in detaching \n");
	}
 

return 0;
}