title: how to exit a child process - _exit() vs. exit
body: <p>Consider this code snippet:</p>
  
  <pre><code>pid_t cpid = fork();
  
  if (cpid == -1) {
      perror("fork");
      exit(EXIT_FAILURE);
  }
  
  if (cpid == 0) { // in child
      execvp(argv[1], argv + 1);
      perror("execvp");
      _exit(EXIT_FAILURE);
  }
  
  // in parent
  </code></pre>
  
  <p>How shall I exit the child process if execvp returns? Shall I use exit() or _exit()?</p>