title: How to strlen of a multi-language string
body: <p>I want to get strlen() of Shift-jis and Utf-8, then compare them.
  A string could be mixed "ああ12345678sdfdszzz". I tried to use strlen but it generates the different results. mb_strlen also doesn't help because this is a mixed string.</p>
  
  <p>For example:</p>
  
  <pre><code>ああ12345678 &gt;&gt; strlen() = 24 chars
  ああああああああああああああああ &gt;&gt; strlen() = 48 chars
  ああああああああああああああああああ &gt;&gt; strlen() = 54 chars
  </code></pre>
  
  <p>It seems to be there is no rule. So <strong>what is the best way to calculate strlen and compare them in multilanguage</strong>?</p>