diff --git a/include/polarssl/xtea.h b/include/polarssl/xtea.h
index 12a9455..21f0edf 100644
--- a/include/polarssl/xtea.h
+++ b/include/polarssl/xtea.h
@@ -61,7 +61,7 @@
  * \param input    8-byte input block
  * \param output   8-byte output block
  *
- * \return         0
+ * \return         0 if successful
  */
 int xtea_crypt_ecb( xtea_context *ctx,
 		 int mode,