/*Code open-sourced by http://codejar-lab.in
This is only for study purpose only and if you found any error use own logic to correct it so dont comment error.
*/
#include<stdio.h>
#include<sys/ipc.h>
#include<sys/wait.h>
#include<sys/shm.h>
int FFork(int iProcess)
{
int iCount;
int PId;
for (iCount=1; iCount<iProcess; iCount++)
{
PId = fork();
if (PId == 0)
return(iCount);
}
return(0);
}
void FJoin(int nProc,int PId)
{
int iCount;
if (PId == 0)
for (iCount=1; iCount<nProc; iCount++)
wait(0);
else
exit(0);
}
void *sshared (int size, int *shmid)
{
*shmid=shmget ( IPC_PRIVATE, size,0666 | IPC_CREAT);
if (*shmid < 0)
{
printf("Error, cannot share memory");
exit(0);
}
return shmat(*shmid,0,0);
}
void cleanup_memory(int *shmid)
{
struct shmid_ds *buf;
if (shmctl(*shmid,IPC_RMID,buf) !=0)
{
printf("Error, cannot free memory");
exit(0);
}
}
int main()
{
int a[10]={1,2, 3,4, 5,6, 7,8, 9,10};
int pid,j;
int *sum,shmid;
sum=(int *)sshared(sizeof(int)*5,&shmid);
pid=FFork(5);
printf("Current process : %d" ,pid);
for(j=pid;j<pid+2;j++)
{
sum[pid] = sum[pid] + a[j] ;
}
FJoin(5,pid);
printf("[1] = %d\n", sum [0] );
printf("[2] = %d\n", sum [1] );
printf("[3] = %d\n", sum [2] );
printf("[4] = %d\n", sum [3] );
printf("[5] = %d\n", sum [4] );
printf("Total sum = %d\n", sum[0] + sum[1] + sum[2] + sum[3] + sum[4]);
}
How to run it? $gcc file.c
$./a.out
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