UCI ponder confusion

[TonyJH]

Things seem to be different in contrast to what my initial thoughts were on your statement about "Polyglot trying to send". According to wikipedia and other sources, and according to what I learned about pipes, a pipe is buffered itself, with a buffer size of 4k or 8k IIRC. And that buffer is independent from the buffered or unbuffered I/O settings of the processes connected with the pipe. I checked it with a small test program, if you like I can post it.

So in our case this would mean that Polyglot does _not_ block when sending even if the engine were not yet ready for reading input. So Polyglot writes "stop", then changes its internal state somehow, then continues immediately with sending the position to search now, all independent from what the engine does - provided the engine is still alive.

That's how I currently think it works. But that does not mean that I fully understand why only few engines require the SyncStop setting.

Sven

Ok, that makes sense. Thanks for the explanation!