title: Creating a UTF-8 string from hexadecimal code
body: <p>In C++, it's possible create a UTF-8 string using this kind of notation: <code>"\uD840\uDC50"</code>.</p>
  
  <p>However this doesn't work in PHP. Is there a similar notation?</p>
  
  <p>If not, is there any built-in way to create a UTF-8 string knowing its Unicode code point?</p>