Zugg Software :: View topic

Beginner Joined: 06 Feb 2004 Posts: 17 Location: USA

I bout the combo pack of zMUD and zMAPPER and I love both from my time using them. Since I have downloaded and installed zMAPPER I have run into a problem. I have it set to keyboard creation and each time I make a new room it makes an error sound but still makes the room. When I make too many room in a short period of time, say like 10 it pops up with an error about memory access problems of some kind. I tried uninstalling zmapper and reinstalling it with no success, has anyone else had this problem?

Posted: Thu Apr 22, 2004 2:48 am

Hmm, this was a problem in a previous version of zMapper. The shopping cart had the old version of zMapper for a while, so maybe you got the wrong file. Try downloading the latest version of zMapper from the Download page here and install that over your current version and see if that helps. Make sure it's really version 1.22 that you are running.

Beginner Joined: 06 Feb 2004 Posts: 17 Location: USA

Ok I tried your suggestions Zugg, first downloading from the site again and installing it over what I had in. It still does it so I checked the version running in the About under the Help menu, it confirmed I was running 1.22 BETA. I remembered I had installed an earlier version when I was trying zMapper out before I bout it but I tried a full uninstall and that still did not help. Is there anything left after uninstalling that could still cause this problem when I updated?

Beginner Joined: 06 Feb 2004 Posts: 17 Location: USA

Don't know if it helps but here is an example on an error I get:

Access violation at address 00401DB9 in module 'zMapper.exe'. Write of address 00000618.

Posted: Fri Apr 23, 2004 2:14 am

Nope, unfortunately the error message doesn't actually help...it's a generic access violation.

Can you try coming up with a procedure to reproduce this in a new map? I don't get any error when I use keypad creation here.

Also, you might try using keypad creation within zMUD itself...it has the same feature so you don't actually need zMapper to do this.

Wizard Joined: 14 Oct 2000 Posts: 1368

quote:
Originally posted by Zugg

Nope, unfortunately the error message doesn't actually help...it's a generic access violation.

Can you try coming up with a procedure to reproduce this in a new map? I don't get any error when I use keypad creation here.

Also, you might try using keypad creation within zMUD itself...it has the same feature so you don't actually need zMapper to do this.

Something I don't understand is why a lot of programmers these days don't use the address of the issue to locate the error. If you can write a function to catch the error (there should be a windows API for that I think) you can even walk the stack outputing the stack trace by scanning for adresses to known functions.

Posted: Fri Apr 23, 2004 7:35 pm

Yes, you can do that. However, in 99% of the cases the address points somewhere into the Windows runtime system, so it's worthless in tracking down a problem. Also, the most common cause of an Access Violation is a nil-pointer reference, and that sends Windows to some random memory address that gives the error.

Yes, it's possible to write your own error handler to display more stack information. I did that for a while. However, to make this useful, it required having the symbol table for my routine names stored and the hacker made bad use of that debugging information, so I had to remove it.

But even in that case where I displayed the callback stack, a nil-pointer or other memory error messes up the stack and the results are meaningless.

I'm not saying this is the case for the specific error mentioned here, but take, for example, an access violation given when close a window. When you close a window, Windows is freeing up all of the memory structures used in that window. If one of those memory structures is corrupted, you get an access violation. There is no way to tell what memory structure it was that gave the error...it could have been almost anything from overwriting memory to a nil pointer.

When I'm debugging locally in Delphi, it will try to load the source code when an error occurs if it can. Sometimes it can, sometimes it can't. But it requires the full source code and symbol tables within Delphi to do this. When I'm debugging memory issues I can run other programs that check for proper memory allocation and deallocation and these can sometimes tell me what memory structure is getting corrupted. But often times even those tools can't determine the source of the problem.

What I am saying is that all of the *easy* bugs have been fixed. Anything left at this point is obscure and hard to track down. So, something simple like a stack dump isn't going to help. All that can help is a reproduceable procedure to cause the error to occur which I can then execute on my system here with Delphi running to see if it can point me in the direction of the problem.

Beginner Joined: 06 Feb 2004 Posts: 17 Location: USA

Well Zugg I assume what you want is for a list of each step I take until the errors start happeneing so here it is.

1. I start up zMapper
2. I choose my muds map file
3. After zMapper open the map file with the different zones I click on the zones tab and choose which ever map I plan on working on(NOTE: I have picked every zone map and the errors still happen)
4. I click on Zone|Keyboard Creation
5. I click on the room I want to set as my current position
6. I click on the set current position button thats in the menu bar
7. After that I try mapping with the keyboard and sometimes it will beep and make the room, sometimes it doesnt beep and it makes the room, sometimes it beeps and pops up with an error dialog, and sometimes a bunch of error dialogs pop up (20 or more) and no matter what I do I cant close them because they reappear as soon as I close them, when that happens I have to kill the process

A NOTE on the beeps, when I am mapping I can me making a few rooms, say in an easterly direction and it wont be beeping. When I change direction towards the south I might get a beep or I might not. The thing I think matters most is that if it does beep when I go south it will beeping every time I go south until I change direction. When I do change direction it might continue to beep and it might not. If it doesn't It wont beep as long as I stay in that new direction.

Hope that info helps cause I really wanna get it all working correctly.

SubAdmin Joined: 18 Nov 2001 Posts: 5182

I was able to replicate this readily with a new blank map as well. The first error message was "Invalid Pointer" and the second simply crashed the mapper completely. Speed of key presses and room creation seems to matter, direction doesn't.

Windows XP SP1
Athalon 1GHz 368MB

Wanderer Joined: 01 Jul 2002 Posts: 81 Location: USA

I have the same problem. I just use zMud to create rooms now and then use zMapper to edit them.

Beginner Joined: 06 Feb 2004 Posts: 17 Location: USA

I had a friend of mine try replicating this on a freshly re-formatted computer and he had the same problems I did. So it appears that it is a bug.

Since it doesnt happen in zMud's built-in mapper I would gather that it has something to do with how room creation is done in zMapper. I know the two mappers are supposed to be identical in most respects so It might also have something to do with a unique feature that applys to only zMapper.

Posted: Tue Apr 27, 2004 5:31 am

zMapper hasn't been compiled with the latest code from zMUD 7.05, so that's probably the difference.

Beginner Joined: 06 Feb 2004 Posts: 17 Location: USA

Would recompiling it with the new code from 7.05 fix the problem or no?

Posted: Tue Apr 27, 2004 6:43 pm

Perhaps, and when I get some time I might do that, but as I announced several months ago, my time is being spent on other projects right now. Since this function works in zMUD, it's not a critical issue at this point and isn't effecting a lot of people.