NSU CSE 323 (IHa) Spring 2018

1410575042.c

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

int main( void )
{
    int shmId;
    key_t key;
    int *shmAddr, *s;
    int i;
    pid_t pid = getpid();
    key = 5678;
    if ((shmId = shmget(key, sizeof(int), IPC_CREAT | 0666)) < 0) {
        perror("shmget");
        exit(1);
    }
    if ((shmAddr = shmat(shmId, NULL, 0)) == (int *) -1) {
        perror("shmat");
        exit(1);
    }
    *shmAddr = 0;

    for(i=0; i<100; i++)
    {
        if(fork() == 0)
        {
            for(i=0; i<100; i++)
            {
                printf("%d + 1 = ", *shmAddr);
                *shmAddr = *shmAddr + 1;
                printf("%d\n", *shmAddr);
            }
        }
        else
        {
            wait(NULL);
        }
    }
    
    exit(0);
}