From d7168a4ea480fae135440de4cdd563f3aae2dc12 Mon Sep 17 00:00:00 2001
From: Stefan Wahren <info@lategoodbye.de>
Date: Mon, 13 May 2013 08:47:19 +0200
Subject: [PATCH] Fix return value and error message

---
 mbus/mbus-serial.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mbus/mbus-serial.c b/mbus/mbus-serial.c
index 16fe6a4..ccd8ce4 100755
--- a/mbus/mbus-serial.c
+++ b/mbus/mbus-serial.c
@@ -291,7 +291,8 @@ mbus_serial_recv_frame(mbus_handle *handle, mbus_frame *frame)
     // Make sure serial connection is open
     if (isatty(handle->fd) == 0)
     {
-        return -1;
+        fprintf(stderr, "%s: Serial connection is not available.\n", __PRETTY_FUNCTION__);
+        return MBUS_RECV_RESULT_ERROR;
     }
 
     memset((void *)buff, 0, sizeof(buff));