Meaningful error codes instead of plain -1

libuavcan/include/uavcan/error.hpp

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2014 Pavel Kirienko <pavel.kirienko@gmail.com>
+ */
+
+#pragma once
+
+namespace uavcan
+{
+/**
+ * Common error codes.
+ * Functions that return signed integers may also return inverted error codes,
+ * i.e. returned value should be inverted back to get the actual error code.
+ */
+enum
+{
+    ErrOk,
+    ErrFailure,
+    ErrInvalidParam,
+    ErrMemory,
+    ErrDriver,
+    ErrUnknownDataType,
+    ErrInvalidMarshalData,
+    ErrInvalidTransferListener,
+    ErrNotInited,
+    ErrRecursiveCall,
+    ErrLogic
+};
+
+}