title: Detecting end of string without using functions
body: <p>How to find out end of PHP string? I have one task: recognize string length without any functions. I know all strings in PHP ends with null byte (<code>\0</code>), but I can't know elements of string after last symbol.</p>
  
  <p>For example, this will not work:</p>
  
  <pre><code>while($a[++$length]);
  </code></pre>
  
  <p>How to know length of string without using any functions?</p>