OK, I will try to include the book stuff in the backend in tomorrow. I will use the -polyglotBook parameter for the filename, and for starters just use directly proportional probabilities. Only picking the best move seems to defeat the most important purpose of the book anyway.
Great!
How am I supposed to react to the "HasOwnBook" options? Should I also suppress accessing of the GUI book for engines that have this option set? What does Polyglot (or the engine) use this information for?
Polyglot ignores this information. If you tell Polyglot to use a book then it will move on behalf of the engine. I.e. the book of the engine does not come into play (except of course when the PG book runs out and the engine book has moves left).
OK, it seems to work now. Not only in two-machines mode, but also with machine white and machine black. Both engines use the book given in the engine-settings menu (UCI... menu for WinBoard), when the useBook option is ticked.
