+PB_GET_ERROR
+------------
+Get the current error message from a stream, or a placeholder string if
+there is no error message::
+
+ #define PB_GET_ERROR(stream) (string expression)
+
+This should be used for printing errors, for example::
+
+ if (!pb_decode(...))
+ {
+ printf("Decode failed: %s\n", PB_GET_ERROR(stream));
+ }
+
+The macro only returns pointers to constant strings (in code memory),
+so that there is no need to release the returned pointer.
+
+PB_RETURN_ERROR
+---------------
+Set the error message and return false::
+
+ #define PB_RETURN_ERROR(stream,msg) (sets error and returns false)
+
+This should be used to handle error conditions inside nanopb functions
+and user callback functions::
+
+ if (error_condition)
+ {
+ PB_RETURN_ERROR(stream, "something went wrong");
+ }
+
+The *msg* parameter must be a constant string.