#include <unistd.h>   /* exec, getcwd */
#include <stdio.h>    /* printf */
#include <sys/types.h> /* need for wait */
#include <sys/wait.h>  /* wait() */


/* Exec example code */
/* This program forks and the child process
   exec's execs "/bin/ls"

  The parent waits for the child process to die,
  then prints out a message
 */

void child(void) {
  int pid = getpid();

  printf("Child process PID is %d\n",pid);
  printf("Child now ready to exec ls\n");
  execl("/bin/ls","ls",NULL);
}
 
void parent(void) {
  int pid = getpid();
  int stat;

  printf("Parent process PID is %d\n",pid);
  printf("Parent process is waiting for child\n");
  wait(&stat);
  printf("Child is done. Parent now transporting to the surface\n");
}

void main(void) {
  printf("In main - starting things with a fork()\n");
  if (fork()) {
    /* fork() returned a non-zero so this is the parent */ 
    parent();
  } else {
    /* fork() returns a zero so this is the child */
    child();
  }
  printf("Done in main()\n");

}