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Find out what called Finalize?Hi everyone,
I have a long-running application (sits in the system tray waiting for something to do and interacts with the user via form and some hardware) containing an object (a reference to the aforementioned hardware and its associated functionality) that occasionally will become 'nothing' i.e. when I attempt to access it after a period of time, I get a null reference exception. I couldn't find a path in my code that releases the object unintentionally, so I was wondering if there was a way to tell if the garbage collector released it or what. This object implements IDisposable because it contains some unmanaged resources- it wraps a device driver- but I haven't had any luck in finding out what chunk of code called Dispose. Any suggestions that would help me troubleshoot this problem? I'd really appreciate it. Mike,
>This object implements IDisposable because it contains Can't you simply put a breakpoint in Dispose?>some unmanaged resources- it wraps a device driver- but I haven't had any >luck in finding out what chunk of code called Dispose. Mattias -- Mattias Sjögren [C# MVP] mattias @ mvps.org http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com Please reply only to the newsgroup. Actually, it's not something that I've been able to reproduce while
debugging, as it is difficult to simulate the operating environment. When the application is under heavy use by our people it occurs more frequently. I can set up a log to write data to a file in the dispose method, but I'm not sure what the most useful data to record would be. Also, are there situations in which the dispose method might not get called? It's a fairly new area for me, as I've pretty much always worked with managed code and haven't had to worry about Dispose. Mike Show quote "Mattias Sjögren" wrote: > Mike, > > >This object implements IDisposable because it contains > >some unmanaged resources- it wraps a device driver- but I haven't had any > >luck in finding out what chunk of code called Dispose. > > Can't you simply put a breakpoint in Dispose? > > > Mattias > > -- > Mattias Sjögren [C# MVP] mattias @ mvps.org > http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com > Please reply only to the newsgroup. > You could add some diagnostic test code to capture the creator's callsite
(use the StackWalk to find it), and then write that out if the object gets finalized or disposed. Or you could save the entire stack trace when the object is created. If you implement both Dispose and a finalizer you will get notified when it either is explicitly destroyed (Dispose) or if it is no longer reachable (the creator abandoned it) when the Finalizer is called. So long as the object is reachable the GC will not collect it; it wont just go away on its own. Show quote "Mike Eaton" <MikeEa***@discussions.microsoft.com> wrote in message news:D70BF082-841D-4CB4-8E23-1351E90C3395@microsoft.com... > Actually, it's not something that I've been able to reproduce while > debugging, as it is difficult to simulate the operating environment. When > the application is under heavy use by our people it occurs more > frequently. > > I can set up a log to write data to a file in the dispose method, but I'm > not sure what the most useful data to record would be. Also, are there > situations in which the dispose method might not get called? It's a > fairly > new area for me, as I've pretty much always worked with managed code and > haven't had to worry about Dispose. > > Mike > > > > "Mattias Sjögren" wrote: > >> Mike, >> >> >This object implements IDisposable because it contains >> >some unmanaged resources- it wraps a device driver- but I haven't had >> >any >> >luck in finding out what chunk of code called Dispose. >> >> Can't you simply put a breakpoint in Dispose? >> >> >> Mattias >> >> -- >> Mattias Sjögren [C# MVP] mattias @ mvps.org >> http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com >> Please reply only to the newsgroup. >>  |
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