Re: Access Violation using CCriticalSection in DLL

From:

"Doug Harrison [MVP]" <dsh@mvps.org>

Newsgroups:

microsoft.public.vc.mfc

Date:

Sat, 07 Apr 2007 11:25:43 -0500

Message-ID:

<v5hf13hpiv3vckd6mcengdv9rvib06p9qp@4ax.com>

On Sat, 7 Apr 2007 09:27:56 -0600, "Brian Westcott" <bwestcott@shaw.ca>
wrote:

I have a log program that uses a CRiticalSection to synchronize writes to
the log file. It works OK in most of my programs. When I Load a DLL (That I
wrote) , I pass the address of the log program by reference to the DLL. When
I call the log program from within the DLL, I get an access violation when
the log program calls CCriticalSection::Lock after formatting the data to be
logged. When I compile and test all programs in Debug mode, the log program
works OK.
I am declaring the logger outside of the scope of my main program so
presumably that makes it global?
Can anyone tell me what is going on?

I think you must be using the word "program" when you mean "function", and
this makes your message a little confusing. Where are you declaring the
CCriticalSection? If its lifetime has ended by the time the DLL calls it,
you will have problems. That said, if the rest of your program can use it
successfully at the same time the DLL has problems, that would rule out a
lifetime issue. After verifying the CCriticalSection should still be valid
at the time the DLL uses it, and double-checking that "formatting the data"
isn't causing any buffer overflows, I'd compile the release mode version
with debug info and see if I could spot anything wrong under the debugger.

--
Doug Harrison
Visual C++ MVP