Access Violation at 0x50466a79 when closing IE

MPCLLC · Post by **MPCLLC** » Fri Oct 21, 2005 9:27 pm

I'm using TeeChart AX 7.0.0.5 on a popup window within internet explorer. We are displaying a bar chart with some of the tool tips turned on. If it makes any difference, we have our own VB activeX wrapper control around TeeChart so that our application can interact with the charts more easily.

Whenever we close out of IE after having utilized this feature of our application, we get a second-chance access violation error (0xc0000005) as follows:

The instruction at "0x50466a79" referenced memory at "0x...". The memory could not be "read". Click OK to terminate the program

I first ran into the problem with version 7.0.0.3, where the instruction address was slightly different (0x504661f1); I grabbed v7.0.0.5 hoping it might fix the problem, since the changelog does mention a similar sounding scenario that was fixed.

We have no debug symbols available for TeeChart so it's a little difficult to get much useful info from the debugger. However, the call stack at this point goes through some operating system files and msvbvm60 and into teechart7.ocx without going through our wrapper control, and our control's termination code has already been called, so our best guess so far is that teechart is trying to clean up some memory that we've already cleaned up; we're just not sure what.

Can anyone at Steema give me any idea what function is involved with the above-mentioned memory address? Or otherwise assist with trouble-shooting this problem?

Thanks,
- Kevin

Post by **Pep** » Fri Oct 28, 2005 10:44 am

Hi Kevin,

yes, we did some changes in the code in order to fix some problems relative to TMarksTipTool.
Maybe in some cases still giving problems. For this reason we've added a new Tool : "Rectangle Tool" which allows you to Simulate the MarkTipsTool using the Canvas techniques. It could be an alternative in your case.
Besides we'll apreciate if you could post an example (maybe you've sent it to us before, but just in case..) so we can review it and try to find a solution in this special case. You could post it on our newsgroups at news://www.steema.net/steema.public.attachments

MPCLLC · Post by **MPCLLC** » Mon Oct 31, 2005 7:14 pm

I have not previously posted a sample of this error. It's occuring within a rather large-scale application and may not be easy to build a standalone repro of this bug, but we'll give it a shot.

Are there any other options if we're unable to get a standalone repro?

Post by **Pep** » Fri Nov 04, 2005 5:44 pm

Hi Kevin,

a sample project is required if it's possible. Having a sample app we can check where the problem comes and fix it. Without having it we can try to reproduce it but maybe we will not do the necessary steps.

MPCLLC · Post by **MPCLLC** » Mon Jan 30, 2006 7:04 pm

Update, FYI - another developer on my team finally had a chance to look at this and found a viable workaround. We were showing the TeeChart on a subclassed dialog opened from Internet Explorer, which displays a TeeChart wrapped within a custom (also sub-classed) User Control. For performance reasons, we don't close or unsubclass dialogs when the user is finished with them -- we simply hide them. Then, when the user closes out of the application, we unsubclass everything.

By adding a WM_CLOSE message to the controls when we unsubclass them, this error message went away.

- Kevin