Question

If a HANDLE is an output parameter, is it necessary to use a reference to the HANDLE or use HANDLE directly?

bool fn(HANDLE h_result); 

or

bool fn(HANDLE&　h_result); 

Answer 1

To return values you can:

1. Use a reference as a parameter
2. Use a pointer as a parameter
3. Actually return the value via return

When you specify the following:

bool fn(HANDLE h_result); 

You are making a copy of h_result. So if you change it in your function, you are changing the copy, not the original.

When dealing with pointers, the concept is exactly the same. Just remember that a pointer is simply a variable that holds a memory address. It doesn’t matter what’s in that memory address. If you want to return a memory address via a parameter, then you need to use a pointer to a pointer or a pointer reference.