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HeReSY
13th January 2011, 20:34
Hi,

where can i find information about what is going on in the librarys from Qt.

My appllication crashes at the adress 1a38dc in the qtgui4.dll.
Is it possible to check which function is called, so that i can check my code why this happens?
The debug version didn't help, because i can't run it on this machine.

Every help is appreciated

HeReSY
squidge
13th January 2011, 22:43
That's exactly what the debug version is for. Why can't you run it on your machine?
MarekR22
14th January 2011, 10:40
In Qt Creator (or other IDE) run your application in debug mode (play button with beetle on top of it).
When crush happens, you should be able to see call stack in IDE and locate where is problem in your application.
high_flyer
14th January 2011, 11:04
Most probably you don't even need to dwell in the Qt lib since the problem is probably in your code, just the crash it self happens in Qt.
Run your app in a debugger, and see which is the last line in your code before the crash - this is where your problem is.
d_stranz
14th January 2011, 15:08
Most probably you don't even need to dwell in the Qt lib since the problem is probably in your code, just the crash it self happens in Qt.
Run your app in a debugger, and see which is the last line in your code before the crash - this is where your problem is.

Well usually, but not always. If memory has been corrupted earlier by some application code, the problem may not show up until the corrupt memory is accessed. In general though, knowing which line in the app causes the crash usually points in the right direction.

I remember a colleague of mine who spent days debugging through the Motif libraries because he was convinced the code was buggy. Of course, it was his code that was at fault...
high_flyer
14th January 2011, 15:40
Well usually, but not always.
Did I say always?
I said probably! :)
d_stranz
14th January 2011, 16:14
I guess I meant to say that the problem may not be
the last line in the code before the crash. However, crashes are almost always the programmer's fault. Except in my code, of course... :D
HeReSY
17th January 2011, 11:52
Thanks for the answers.

I hope i find the crash. I had a memory leak in my application, and sometimes it crashes.
That never appears on my machine, because my machine had much more ram than the testmachine.