> Thanks Robert,
> We actually found the issue to be in the C-runtime library. I was using
> the flag /MDd which uses the debug version of the multithread, DLL specific
> version of the runtime library. Changing this to the non-debug version
> (/MD) works fine.
> If I use only C++, so I have a console application with a main method that
> uses this DLL, either runtime library works fine in visual studio. However,
> the python/cython/C++ setup has this issue. Though I still don't know the
> exact problem, for us the fix is to use the non-debug version of the
> runtime library.
> In cython, when we define a new C++ object, Python or Cython must be
> allocating memory for it. Closest explanation I found is that the same
> runtime library needs be responsible for allocating and deallocating the
> memory. The debug version allocates the requested memory plus some
> additional memory for book-keeping. So the debug runtime library maybe
> trying to delete this additional memory; however, since I'm not using debug
> versions of python/cython, they are likely using the non-debug versions of
> the runtime library, in which case, there is no additional memory for the
> debug version to delete.
Yep, that would explain exactly what's going on. Thanks for following up.
> On Monday, October 22, 2012 6:15:36 PM UTC-7, Robert Bradshaw wrote:
>> Don't have Windows myself, but I might try trying to reproduce this
>> error in a single function (that allocates then deletes the object)
>> and then into a (non-Python) example you could ask on visual studio
>> mailing lists.
>> On Mon, Oct 22, 2012 at 4:09 PM, Jasmine Sandhu
>> <sandhu....@gmail.com> wrote:
>> > Hi,
>> > I'm wrapping a C++ class that has a virtual destructor in the base
>> class.
>> > The python/cython/c++ application needs
>> > to run on windows and Mac OS X.
>> > On Windows:
>> > -----------
>> > I compile the C++ into a DLL and link the cython extension with it. The
>> > compilation works fine;
>> > however, when I run the test, I get a runtime error in the Microsoft
>> Visual
>> > C++ Debug Library:
>> > 'Debug Assertion Faled!'
>> > See error here: http://www.nimret.org/jasmine/**
>> stuff/DebugAssert_error.jpg<http://www.nimret.org/jasmine/stuff/DebugAssert_error.jpg>
>> > The virtual destructor in the base class causes the problem.
>> > I have reproduced the problem in a simple example. The files are at:
>> > http://www.nimret.org/jasmine/**stuff/<http://www.nimret.org/jasmine/stuff/>
>> > The example:
>> > ------------
>> > 1. Base.cpp - base class with virtual destructor
>> > 2. Rectangle.cpp - derived class with over written destructor
>> > The cython (pyx) code is a wrapper around the Rectangle object.
>> > It instantiates Rectangle, defines python methods to wrap the C++
>> methods.
>> > At the end it deletes the Rectangle object.
>> > I've stepped through the debugger in Visual Studio and
>> > am also printing statments. The application seems to step through as
>> > expected:
>> > 1. base class constructor
>> > 2. derived class constructor
>> > 3. calls a method and prints output
>> > 4. Invokes __dealloc__ at the end of life
>> > 5. derived class destructor
>> > 6. base class destructor
>> > Then I get the 'Debug Assertion Failed!' error.
>> > On the Mac, I'm building the C++ files with the cython (pyx) all in one
>> > shared object.
>> > It runs and exits cleanly.
>> > Has anyone gotten virtual destructors to work in cython on the Windows
>> side?
>> > This is currently blocking us in wrapping existing C++ code to use in
>> > Python.
>> > Thanks!
>> > Jasmine
