diff --git a/src/Codeception/Command/Shared/FileSystem.php b/src/Codeception/Command/Shared/FileSystem.php
index 86a69acefb..a3832647ed 100644
--- a/src/Codeception/Command/Shared/FileSystem.php
+++ b/src/Codeception/Command/Shared/FileSystem.php
@@ -43,7 +43,7 @@ protected function removeSuffix($classname, $suffix)
         return preg_replace("~$suffix$~", '', $classname);
     }
 
-    protected function createFile($filename, $contents, $force = false, $flags = null)
+    protected function createFile($filename, $contents, $force = false, $flags = 0)
     {
         if (file_exists($filename) && !$force) {
             return false;