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

int main(void){
   pid_t pid = fork();
   if (pid == -1){
      exit(EXIT_FAILURE);
   }
   else if (pid == 0) {
      printf("Hello from the child process!\n");
      _exit(EXIT_SUCCESS);  
   }
   else {
      int status;
      (void)waitpid(pid, &status, 0);
   }
   return EXIT_SUCCESS;
}