title: What is the meaning of argv[1][0]?
body: <p>I am reading codes of <code>mcachefs</code> and could not understand some codes, like below:</p>
  
  <pre><code>printf("mcachefs " __MCACHEFS_VERSION__ " starting up...\n");
  
  if (argc == 1 || argv[1][0] == '-')
  {
      fprintf(stderr,
          "\tError : first argument shall be the the mcachefs_mountpoint !\n");
      exit(2);
  }
  </code></pre>
  
  <p>I have two questions:
  1: For <code>printf("mcachefs " __MCACHEFS_VERSION__ " starting up...\n")</code>, is it the correct way to use <code>printf</code>? I have never seen such way of using it.</p>
  
  <ol>
  <li>What is the meaning of <code>argv[1][0]</code>? I know <code>argv[]</code> represents the arguments from the command line. But, is not it a <strong>one dimension</strong> array?</li>
  </ol>