why can't unload vtkCommonCore.dll

Support
1

with vs2013, I use vtk in a mfc dll
(just add four lines #include <vtkAutoInit.h>

VTK_MODULE_INIT(vtkRenderingFreeType);
VTK_MODULE_INIT(vtkInteractionStyle);
VTK_MODULE_INIT(vtkRenderingOpenGL2);
VTK_MODULE_INIT(vtkRenderingVolumeOpenGL2);
),but I found after the main program load mfc dll and unload the mfc dll,it will occur a crash.it will go to 
void vtkCommonInformationKeyManager::ClassFinalize()
{
  if(vtkCommonInformationKeyManagerKeys)
  {
    // Delete information keys.
    for(vtkCommonInformationKeyManagerKeysType::iterator i =
          vtkCommonInformationKeyManagerKeys->begin();
        i != vtkCommonInformationKeyManagerKeys->end(); ++i)
    {
      vtkInformationKey* key = *i;
      delete key;
    }

and show a error as below:

0x00007FFC465BC782 (vtkCommonCore-8.1.dll) conflict
who can tell my why?

2

Hmm. My guess is that you’re linking against one VTK build, but at runtime, a different one is being found. However, I suspect that unloading the VTK libraries just isn’t supported in general (it’s not a common use case).