Question

I would look this up, but honestly I wouldn’t know where to start because I don’t know what it is called. I’ve seen variables passed to functions like this:

myFunction((void**)&variable);

Which confuses the heck out of me cause all of those look familiar to me; I’ve just never seen them put together like that before.

What does it mean? I am a newb so the less jargon, the better, thanks!

Answer 1

It’s a cast to a pointer to a void pointer.

You see this quite often with functions like CoCreateInstance() on Windows systems.

ISomeInterface* ifaceptr = 0;
HRESULT hr = ::CoCreateInstance(CLSID_SomeImplementation, NULL, CLSCTX_ALL,
    IID_ISomeInterface, (void**)&ifaceptr);
if(SUCCEEDED(hr))
{
    ifaceptr->DoSomething();
}

The cast converts the pointer to an ISomeInterface pointer into a pointer to a void pointer so that CoCreateInstance() can set ifaceptr to a valid value.

Since it is a pointer to a void pointer, the function can output pointers of any type, depending on the interface ID (such as IID_ISomeInterface).