beginner question: void ** ?

[strugggling]

hi to everyone...

can someone explain
void **
used in the following context


interface IFoo1: public IUnknown
{
...
};

IFoo1* pIFoo1 = NULL;
HRESULT hr = ::CoCreateInstance(CLSID_Component, NULL,
CLSCTX_INPROC_SERVER,
IID_IFoo1,
(void **) &pIFoo1);

 

[LazyMe]

That would be a pointer to a IFoo pointer, casted to a pointer to a void*.

Maybe more clear: The address in which a pointer to the IFoo interface will be placed after the call to CoCreateInstance has succeeded.

Greetings,
Rick

 

[sambasivamkannan]

If we passed only the pointer we can't change the value of thepointer(we can only change the contents pointed to by the pointer). So we pass the address of the (interface) pointer. so we need another level of indirection. CoCreateInstance() takes a void** parameter. So we need to type cast the actual parameter to void**.
-S.Kannan