Add missing doc

include/starpu_task_util.h

@@ -88,7 +88,19 @@ extern "C"
    execute the codelet.
 */
 #define STARPU_EXECUTE_ON_DATA	 (7<<STARPU_MODE_SHIFT)
+
+/**
+   Used when calling starpu_task_in_sert(), must be followed by an array of
+   handles and the number of elements in the array (as int). This is equivalent
+   to passing the handles as separate parameters with STARPU_R/W/RW.
+*/
 #define STARPU_DATA_ARRAY        (8<<STARPU_MODE_SHIFT)
+
+/**
+   Used when calling starpu_task_in_sert(), must be followed by an array of
+   struct starpu_data_descr and the number of elements in the array (as int).
+   This is equivalent to passing the handles with the corresponding modes.
+*/
 #define STARPU_DATA_MODE_ARRAY   (9<<STARPU_MODE_SHIFT)
 
 /**