title: DateTime::createFromFormat in PHP < 5.3.0
body: <p>I'm looking for a function identical to <a href="http://www.php.net/manual/en/datetime.createfromformat.php" rel="nofollow noreferrer">DateTime::createFromFormat</a> but I need it to work in an environment running a version of PHP which is older than v5.3.
  Basically I need to provide a format, like you'd use with the <a href="http://php.net/manual/en/function.date.php" rel="nofollow noreferrer">Date()</a> function, and I then need to parse/validate a string against that format, and return a timestamp if the string is formatted correctly and a valid date.</p>
  
  <p>Anyone know where I can find something like that, or do I have to write it myself?</p>
  
  <p>Again, this has to work with a specific format, provided as an argument. The format could be anything, so there's no guarantee I can just use <a href="http://php.net/manual/en/function.strtotime.php" rel="nofollow noreferrer">strtotime()</a>.</p>