diff --git a/core/lib/Drupal/Component/Utility/OpCodeCache.php b/core/lib/Drupal/Component/Utility/OpCodeCache.php
index eb17c0d..afc1497 100644
--- a/core/lib/Drupal/Component/Utility/OpCodeCache.php
+++ b/core/lib/Drupal/Component/Utility/OpCodeCache.php
@@ -27,13 +27,17 @@ public static function invalidate($pathname) {
     clearstatcache(TRUE, $pathname);
 
     if (extension_loaded('Zend OPcache')) {
-      opcache_invalidate($pathname, TRUE);
+      \opcache_invalidate($pathname, TRUE);
     }
-    if (extension_loaded('apc')) {
+    // If apcu extenstion is enabled in PHP 5.5 or greater it emulates apc.
+    // This is to provide an easy upgrade path if you are using apc's user
+    // caching however the emulation does not extend to opcode caching.
+    // Therefore we need to check if the function exists as well.
+    if (extension_loaded('apc') && function_exists('apc_delete_file')) {
       // apc_delete_file() throws a PHP warning in case the specified file was
       // not compiled yet.
       // @see http://php.net/manual/en/function.apc-delete-file.php
-      @apc_delete_file($pathname);
+      @\apc_delete_file($pathname);
     }
   }