FIX: _variant_t::operator IUnknown*() Fails To AddRef Interface (174635)

MORE INFORMATION

The code below should be called instead of allowing _variant_t::operator IUnknown*() to be implicitly called to work around this problem. The conversion operator will be called whenever a conversion from _variant_t to IUnknown* is required. One place this occurs is with assignment statements, another is passing a _variant_t to a function that expects an IUnknown*.

Sample

  IUnknown* f( const _variant_t & vt )
  {
      if (V_VT(&vt) == VT_UNKNOWN)
      {
          V_UNKNOWN(&vt)->AddRef();
          return V_UNKNOWN(&vt);
      }
      _variant_t vttmp;

      vttmp.ChangeType(VT_UNKNOWN, &vt);

      V_UNKNOWN(&vttmp)->AddRef();
      return V_UNKNOWN(&vttmp);
   }
   void g()
   {
     _variant_t vt;
     IUnknown * punk=0;
     // ...some code...
     punk = vt;    // will cause _variant_t::operator IUnknown*()
                   // to be called. Comment this out.
     //punk = f(vt); // call f instead. Uncomment for workaround
     // ...more code...
   }