Hi,

I'm trying to put together some managed and unmanaged code.  Everything
works fine until the program exits, and I suppose the garbage collector
runs to finalize things.  Then I get:

Unhandled Exception: System.NullReferenceException: Object reference
not set to
an instance of an object.
  at std.list<int,std::allocator<int>

  at std.list<int,std::allocator<int>

  at Tab.MCell.Finalize()

I can't think why I would get a NullReferenceException in managed code.
Any ideas greatly appreciated.

The std::list is in unmanaged code:

#include <list>
#include <math.h>

using namespace std;

namespace Tab {

 class __declspec(dllexport) Cell
 {
 private:
   int _row;
   int _col;
   list<int> _vals;
 ...
  };
}

The managed code looks like:

#using <mscorlib.dll>

#include "Cell.h"

using namespace std;
using namespace System::Collections;

namespace Tab {

 public __gc class MCell
 {
 //
 // DATA
 //
 private:
   Cell __nogc *_cell;
 //
 // FUNCTIONS
 //
 public:
   MCell(Cell *c)
     { _cell = c; }
   MCell(int row, int col)
     { _cell = new Cell(row, col); }
   ~MCell()
     { _cell->~Cell(); }
...
 };
}

The unmanaged code is built with the following which makes a DLL (the
8.3 directories are just where the stl stuff is on my machine):

cl -GX  -I"C:\PROGRA~1\MIA4C6~1\include"   Cell.cc /LD /link
/libpath:"C:\PROGRA~1\MIA4C6~1\lib"

The executable gets built with:

cl -GX  -I"C:\PROGRA~1\MIA4C6~1\include"   /clr CTest.cc /link
/libpath:"C:\PROGRA~1\MIA4C6~1\lib" Cell.lib

Thanks in advance!

-- Andrew Bell
andrew.bell.ia@gmail.com