Post by Samuel Venable in StockfishChess

GameMaker Studio 2.3.1+ Extension Collection » Community

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Does the crash only happen with fairy-stockfish? Or does it happen with the default stockfish app which comes with the extension? It is my understanding the demo doesn't come with fairy-stockfish in specific, so it wasn't intended for that. Another user on discord already reported this to me with fairy-stockfish, and they ended up using a different chess engine entirely as their workaround to solve this issue. Unfortunately, this demo was made for a client and they seemed happy with it, but I can't comment much on the stability of it because while I did write the demo I don't actually know much about stockfish or command line chess engines as a whole, so I'm not the person to be much a help here. The demo was meant to show what can be done from the command line with various apps, and stockfish was just the command line app chosen for the demo, and mileage will vary across command line apps.

Also, I can't remember who pinged me on discord about stockfish, and I have way too many messages to dig through of support tickets to really go about finding who they were much less what chess engine they settled on; maybe if they read this topic they could comment and help you out.

I apologize for the inconvenience. I was never able to figure out the root cause of the crash and I've already spent as much time on trying to figure that one out as I would like.

One thing to make note of with any command line app you try to read standard output from is the buffer might overflow, which causes crashes. This happens when the string returned and sent to standard output is too large for the app to hold it in memory, and so it will close abruptly (crash) in such case. The extension used to store standard output in a string, called xProcess, does not truncate the string at all if it gets too big, though I doubt buffer overflow is the reason you get the crash you are facing. This note is more of a "so you know" for general rule of thumb in case you, (or anyone else for that matter), uses my xProcess extension for anything besides stockfish.

Byte GameMaker Magazin119 days ago

fairy-stockfish was just an example. It was derived from Stockfish. I have tested it with several UCI engines, including all Stockfish versions from 12 to 16, Polyfish, Komodo Dragon and others. When exactly the crash occurs varies. This also depends on how the chess engine was compiled. With fairy-stockfish it runs reasonably stable at a depth of 12 half-moves. It "only" crashes every 100th game. But 12 half-moves is far too little to do anything sensible with it.

A buffer overflow was my first assumption. So I installed it in between so that after each move the engine is restarted, FEN is sent and global.output="" is set. Unfortunately, that didn't help. There were also problems because I change the engine in the middle of the game, but I solved that. Now it is called, I send FEN for every move, but it runs through.

My current guess is this: Greater depth means that the engine pauses at some point, so it doesn't send anything. I suspect that because the EXE is not responding, synchronization is lost.

If you give me another contact, Discord or mail, I can also send you screenshots or the current version. It's a pretty big project by now and it would be a shame if it were to fail.

Samuel Venable115 days ago

My discord is "samuelvenable". Try downloading the project again and see if the new version of the extension fixes it. I added a new function which allows you to limit the buffer length to a specific number of characters, (including the null byte at the end). For example:

SetBufferLimitForStandardOutput(2048);

...will limit the buffer to 2,048 of the most recent characters.

Byte GameMaker Magazin115 days ago

It's great that you're still working on it. I have tested your version. It crashes for me at a depth of 40.

ExecutedProcessWriteToStandardInput(global.pid, "go depth 40\n");

I'll get in touch with you via Discord when I get a chance.

itch.io

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