[solved] OpenTTD hangs on Sleep()

[yorg]

Hi,

I have been working on an AI for a few days now, and have been having an absolute blast! First and foremost I want to congratulate the developers for creating such an amazing addition to OpenTTD. I don't even think I play OpenTTD anymore, when ever it's open it's 'cause i'm working on my AI. I'm looking forward to having something complete enough to share fairly soon.

I have just run into a problem that is really confusing me at the moment. My Start() function begins like this:

Code: Select all

AILog.Info("Welcome to robotAI.")
this.Sleep(1);
this.SetCompanyName();
this.name = AICompany.GetCompanyName(AICompany.MY_COMPANY);
AILog.Info("INIT: Name set: " + this.name);
this.Sleep(1);
this.myCargo = this.ChooseBestCargo(AICargo.CC_BULK);	
AILog.Info("INIT: Gonna go for cargo #" + myCargo);
this.Sleep(1);

I never had a problem with this until about 10 minutes ago, while I was working on a completely different part of the program. Now whenever I try to load my AI, it gets as far as the last Sleep() call in the code above, then OpenTTD hangs with my processor running at 100% utilization. If I remove that Sleep() call, the same thing happens at the Sleep() call before. I have tried changing Sleep(1) to Sleep(0) with the same results, and removing all three of the calls causes OpenTTD to hang after the first line.

I have looked through the documentation and this forum, and have no idea what could be causing this problem. I am running r13532 under Ubuntu 8.04, on a 750MHz Pentium 3.

If anyone has any suggestions as to a solution I would be very appreciative!

--
yorg

[Rubidium]

Sounds like an infinite loop that is running after your Sleep. NoAI is going to have a system that will let each AI run a few hundred lines of code each game tick, so big (and even infinite) loops don't hang OpenTTD anymore, but that is not done yet.

[yorg]

Thanks for your help, Rubidium!

You were right that it was an infinite loop; it was getting stuck endlessly looking for station sites. Since the script was never giving OpenTTD a chance to display it's output I didn't realize it was getting that far in the program.

The problem resulted from the fact that a local variable declared inside a while loop is not seen by the loop itself, eg. this is an infinite loop:

Code: Select all

local count = 0;
while (count == 0) {
   local count = 1;
}

Taking away the "local" on the 3rd line causes the loop to terminate properly.

With this problem out of the way I can on with the fun stuff! Thanks again!