Wait System Call

pid_t wait(int *status);

In order to suspend the parent and handle the child properly, the wait system call is necessary.

/* Wait/wait.c */
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

int main(int argc,char *argv[])
{
    while(1)    
    {
        printf("Press Enter to execute ls");
        while(getchar() != '\n');
        if(!fork())
        { 
            execl("/bin/ls","ls",NULL); 
        } 
        else 
        { 
           wait(NULL); 
        } 
   }
    return 0;
}

wait() takes one parameter for storing the status of the child process, for example, whether it is terminated or suspended. If you are not interested, just put NULL as the parameter.

This is a similar program in Problem 2. However, this can get rid of zombies!