Thread: Problem : Sending Array to Client Process Using Shared Memory

hi i want to send an array to a shared memory.but it should send 4 values at a time.
this code is working. but the client process doesn't read the 1st 4 numbers correctly. can some one help me please.
here is the code,

apologize me i've put the wrong code,
it should be,
main process,

Code:

#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/shm.h>
#define SHMSZ 4
#define SHMSZ2 1

main()
{
	int noofvals=0,i,num,shmid,*shm,*s,shmid2,j;
	char *shm2,*s2;
	printf("Enter the Number Values you enter\n");
	scanf("%d",&noofvals);
	int *arr=malloc(noofvals*sizeof(int));
	for(i=0;i<noofvals;i++)
	{
		printf("Enter the Number %d\n",i+1);
		scanf("%d",&num);
		arr[i]=num;
	}
	printf("Numbers Read\n");
	for(i=0;i<noofvals;i++)
	{
		printf("%d,",arr[i]);
	}
	printf("\n");

	key_t key;
	key=5678;
	if((shmid=shmget(key, SHMSZ, IPC_CREAT | 0666))<0)
	{
		perror("shmget");
		exit(0);
	}
	if ((shm = shmat(shmid, NULL, 0)) == (int *) -1) 
	{
	  perror("shmat");
	  exit(1);
	}
	
	key_t key2;
	key2=5679;
	if((shmid2=shmget(key2, SHMSZ2, IPC_CREAT | 0666))<0)
	{
		perror("shmget");
		exit(0);
	}
	if((shm2=shmat(shmid2, NULL, 0))==(char *) -1)
	{
		perror("shmat");
		exit(0);
	}
	
// 	sending the Number of Values

	printf("Sending the Number of Elements to Receive\n");
	*shm2='w';
	s=shm;
	*s=noofvals;
	while(*shm2!='r')
	{
	  wait(1);//waiting for Clients Reply
	}
	
	printf("Element Count Sent\n");
	*shm=NULL;
// 	sending the Elements
	num=0;
	*shm2='w';
	while(num<noofvals)
	{

	  for(i=0;i<4;i++)
	  {
	    printf("Sending %d\n",arr[num]);
	    *s=arr[num];
	    num++;
	    if(num>=noofvals)
	    {break;}
	    *s++;
	  }
	  printf("\n");
	  *shm2='w';
	  while(*shm2!='r')
	  {
	    wait(1);//waiting for Client's Reply
	  }
	}
	s=shm;
	for(i=0;i<noofvals;i++)
	  {
	    printf("Sent val %d\n",*s);
	    *s++;
	  }
	*shm2='w';
//	Server Exiting
	printf("Server Exiting\n");
}

client process,

Code:

#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/shm.h>
#define SHMSZ 4
#define SHMSZ2 1
main()
{
  	int noofvals=0,i,num,shmid,*shm,*s,shmid2,j;
	char *shm2,*s2;
	key_t key;
	key=5678;
	key_t key2;
	key2=5679;
	if((shmid=shmget(key, SHMSZ, 0666))<0)
	{
		perror("shmget");
		printf("error 1");
		exit(0);
	}	
	if((shmid2=shmget(key2, SHMSZ2, 0666))<0)
	{
		perror("shmget");
		exit(0);
	}
	if ((shm = shmat(shmid, NULL, 0)) == (int *) -1) 
	{
	  perror("shmat");
	  exit(1);
	}
	if((shm2=shmat(shmid2, NULL, 0))==(char *) -1)
	{
		perror("shmat");
		exit(0);
	}
// 	wait till server Sends the Number of Elements
	while(*shm2!='w')
	{
	  wait(1);//waiting for Server to Send Data
	}
	noofvals=*shm;
	*shm=NULL;
	printf("Received the Number of Elements as %d\n",noofvals);
	*shm2='r';
	int arr[noofvals];
	
// 	Receive Elements
	printf("Waiting\n");
	while(*shm2!='w')
	{
	  wait(1);//waiting for Server to Send Data
	}
	s=shm;
	num=0;
	while(num<noofvals)
	{
	  for(i=0;i<4;i++)
	  {
	    printf("Received %d\n",*s);
	    arr[num]=*s;
	    num++;
	    if(num>=noofvals)
	    {break;}
	    s++;
	  }
	  
	  printf("\n");
	  *shm2='r';
	  while(*shm2!='w')
	  {
	    wait(1);//waiting for Client's Reply
	  }
	}
	*shm2='r';

	  
	int div=(int) ((noofvals/2)+1);
	printf("\n\ndiv main - %d, div main2 - %d  \n\n",div,(noofvals-div));
	int *ar1=malloc(div*sizeof(int));
	int *ar2=malloc((noofvals-div)*sizeof(int));
	
	for(i=0;i<div;i++)
	{
	  ar1[i]=arr[i];
	  printf("div - %d - %d\n",i,ar1[i]);
	}

	printf("\n");
	int lp=noofvals-div;
	for(i=0;i<lp;i++)
	{
	  ar2[i]=arr[div];
	  printf("div - %d - %d\n",div,ar2[i]);
	  div++;
	}
	
	for(i=0;i<div;i++)
	{
	  printf("ptr arr %d\n",ar1[i]);
	}
	for(i=0;i<lp;i++)
	{
	  printf("ptr arr2 %d\n",ar2[i]);
	}
}