c++ InterlockedExchangePointer and pointer alignment

Question

The documentation for the InterlockedExchangePointer Function states:

On a 64-bit system, the parameters are 64 bits and the Target parameter must be aligned on 64-bit boundaries; otherwise, the function will behave unpredictably. On a 32-bit system, the parameters are 32 bits and the Target parameter must be aligned on 32-bit boundaries.

I'm compiling for 32bits and the program will run on 32bits and 64bits architectures; does the following structure provide pointers which are usable by InterlockedExchangePointer on any (32 or 64bits) running architecture without code adaptation?

template <class T>
struct Foo {
    enum { count = 3 };
    __declspec(align(64)) T objects[count];
};

(I suppose that if a single pointer is aligned on 64bits it's also aligned on 32bits -- even if there is a padding if running on 32bits)

Thanks.

Answer 1

On 64-bit system program that written for 32-bit platform will work through compatibility layer (WoW, Windows on Windows), and your pointers must be aligned on 32 bits.

But, if you compile your program in 64 bit mode - your pointers will be automaticaly aligned on 64 bits.