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igorg avatar image
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RSearchLib::IRSearchResponse get_Instruments(&l_instruments) throws

I have very strange behavior that I cannot explain.

Every morning I run the program (C++ COM API) that does:

1. Initialize Eikon - Starts desktop application

2. Wait for a response.

3. Create RSearch request and send request

4. Wait for the response.

5. Get response with

l_hr = m_pIRSearchResponse->get_Status(&l_RSearchQueryStatus); where l_RSearchQueryStatus == S_OK.

6. l_hr = m_pIRSearchResponse->get_Instruments(&l_instruments); - this line throws access violation that I cannot catch anyhow.

The problem is it happens every morning once or twice in a row. After I step in debug mode, the error is gone until next morning.

I know it looks weird, but I don't have a way to deal with this crash.I checked m_pIRSearchResponse is not NULL and based on msxml3.dll in the error, it's something internal.

Please check the screenshot:

Any idea why it can happen?

Thanks.

eikoneikon-com-api
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Alex Putkov.1 avatar image
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Your guess is as good as mine. The exception is in a Microsoft DLL. Maybe you should try updating MS XML Parser. Or maybe it's the latest version of the parser that causes the problem.

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igorg avatar image igorg

I checked the versions. I have 3 and 6 with the latest updates.

I don't use msxml in my project. But Eikon COM uses msxml internally, so I have no chance to track the error and find out what call causes it...

Is there a way to tell Eikon to use msxml6?

Alex Putkov.1 avatar image Alex Putkov.1 igorg

Sorry, I wish I had a quick and easy solution for this. But there isn't any. Yes, RSearch library uses MS XML Parser. Even if you had the source code for RSearch library, I don't see how it would help you since the exception is in Microsoft library for which you can't have the source code. Looking at the call stack may or may not provide some clues. But there's no straight way to get to the root cause.

igorg avatar image igorg Alex Putkov.1

If I had the source code I would track the function call of ms xml parser that leads to the exception and report it to the MS.

Based on the error, it's very possible just a NULL de-referencing. It's also possible that some function calls are illegal if xml parser is not initialized yet.

Anyway, there is a few options on your side and almost none on my..

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Alex Putkov.1 avatar image Alex Putkov.1 igorg

The only way to tell any existing application to use MSXML6 is by changing all the version independent ProgIDs in the registry to point to MSXML6 CLSIDs. Unless your application only ever needs to run on one machine, it would be pointless to even try it. Even if you can make it work on one machine, you probably can't control what's on other machines that need to run your application. Besides Microsoft made a huge mess of XML Parser releases and their versioning. The task of forcing an existing application to use a specific version of the XML Parser would certainly not be for a faint of heart.

igorg avatar image igorg Alex Putkov.1

Yes, this is not an option..

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igorg avatar image
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@Alex Putkov.

I believe I found what causes the crash. First of all, it's not just first request per day. It's a first request per day per exchange.

The problem is: eikon's callback function signature looks like :

OnRSearchQueryUpdate(RSearchLib::IRSearchResponse * pIRSearchResponse)

What I do (and what fails) is I pass this pointer to another thread which parses the data.

The call on this pointer crashes if there were no request for this data today. This makes me think Eikon saves the data request/response in its cache and returns a response from its cache without a problem. But if there is no cache yet... it does something not allowed in Single Threaded Apartment environment that leads to crash.

I know how to deal with it in my code, but will test it only in a few hours.

Anyway, it would be nice to get some exception instead of Access Violation.

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