diff --git a/wp-includes/functions-compat.php b/wp-includes/functions-compat.php
new file mode 100644
index 000000000..7a17b0aa6
--- /dev/null
+++ b/wp-includes/functions-compat.php
@@ -0,0 +1,50 @@
+<?php
+
+/* Functions missing from older PHP versions */
+
+
+/* Added in PHP 4.2.0 */
+
+if (!function_exists('floatval')) {
+	function floatval($string) {
+		return ((float) $string);
+	}
+}
+
+if (!function_exists('is_a')) {
+	function is_a($object, $class) {
+		// by Aidan Lister <aidan@php.net>
+		if (get_class($object) == strtolower($class)) {
+			return true;
+		} else {
+			return is_subclass_of($object, $class);
+		}
+	}
+}
+
+if (!function_exists('ob_clean')) {
+	function ob_clean() {
+		// by Aidan Lister <aidan@php.net>
+		if (@ob_end_clean()) {
+			return ob_start();
+		}
+		return false;
+	}
+}
+
+
+/* Added in PHP 4.3.0 */
+
+function printr($var, $do_not_echo = false) {
+	// from php.net/print_r user contributed notes 
+	ob_start();
+	print_r($var);
+	$code =  htmlentities(ob_get_contents());
+	ob_clean();
+	if (!$do_not_echo) {
+	  echo "<pre>$code</pre>";
+	}
+	return $code;
+}
+
+?>
\ No newline at end of file