[DUG] Program crashes - anyone knows why?

[Gajo Csaba]

Thanks Conor, I've added (A) and sent the application to the client, so  
let's hope there will be some progress.


On Sun, 26 Nov 2006 20:35:38 +0100, Conor Boyd <Conor.Boyd at trimble.co.nz>  
wrote:

> That's a very detailed email... ;-)
>
> Without delving deeper, I've a couple of comments/suggestions.
>
> A) You definitely need a try-except block in your Execute method.  You
> must not let unhandled exceptions propagate out of a thread.  Even if
> you only put a call to OutputDebugString in your exception handler, then
> that means you could use e.g. DebugView from Sysinternals to view
> exceptions being thrown.
>
> B) Try adding the madExcept library from www.madshi.net to your
> application.  It should help hugely in tracking down unhandled errors
> like this, especially when they are happening on a remote machine.  You
> can configure it so that in the event of an error, your program can
> automatically email you the error reports including call stacks, etc.
>
> C) You could also try using the URLDownloadToFile function from the
> URLMon unit instead.  I use it in a threaded application, and it works
> fine for me.
>
> I don't know what you're using to access Google, but I've been using the
> Indy components very successfully in one of my projects.
>
> Good luck in trying your error down...
>
> HTH,
>
> Conor
>
> -----Original Message-----
> From: delphi-bounces at ns3.123.co.nz [mailto:delphi-bounces at ns3.123.co.nz]
> On Behalf Of Gajo Csaba
>
> I wrote a multithreaded application for a client and it crashes on the
> client's computer, while it works ok on mine. Can someone give me a clue
> as to what might be the problem?
>
> The program works like this: I have two TThreadLists: one contains a
> list of keywords (~20000) while the other a list of proxy servers
> (~500). When the user clicks on the button, 21 threads are created. 1
> thread directly accesses Google, enters the keyword and processes the
> result. The other 20 threads do the same, except they use a proxy
> server.
>
> OK, so each thread grabs a keyword from the list and then removes it
> from the list, so no one else could use it again. It tries to access the
> internet. If the connection fails then it means the proxy doesn't work,
> so it gets another proxy address from the list. No two threads ever
> share the same proxy. If there are no more free proxies left, the thread
> dies (and returns the unprocessed keyword to the list).
>
> [snip]
>
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>



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