First of all, I need a way to get the pointer to a const object. So I can
write:
QueryInterface(&IID_IPersistFile)
instead of:
var iid = IID_IPersistFile
QueryInterface(addr iid)
And then, I need a way to get the address of string/wstring/mstring to pass
into windows API. Choosing & symbol to do these seems naturally. At last, since
this symbol already have these two functions, so I let it do more, get all
variables' address.
BTW, for string/wstring/mstring, & symbol is not the same as addr. It more like
s[0].addr but aware nil.
