diff -r fdd4f8eb5c83 -r 5ef9d5b14879 include/ecrt.h
--- a/include/ecrt.h	Tue Feb 05 15:24:02 2013 +0100
+++ b/include/ecrt.h	Tue Feb 05 15:24:45 2013 +0100
@@ -1519,16 +1519,16 @@
                                                    registrations. */
         );
 
-#ifdef __KERNEL__
-
 /** Returns the current size of the domain's process data.
  *
- * \return Size of the process data image.
+ * \return Size of the process data image, or a negative error code.
  */
 size_t ecrt_domain_size(
         const ec_domain_t *domain /**< Domain. */
         );
 
+#ifdef __KERNEL__
+
 /** Provide external memory to store the domain's process data.
  *
  * Call this after all PDO entries have been registered and before activating