error/warning handling in embedder

Error messaging. I have no idea how to handle that. Any hints? Currently it prints out some stuff to console. In the ideal case I would like to get the info in a format where I would be able to react to certain error conditions in the UI. For that matter I need to identify the problem precisely. Parsing the output is no good. (how do I redirect it elsewhere at least?

maybe this is just a documentation issue.