UNIONs does not reuse the same memory.

[genius257]

$tUnion = DllStructExCreate("union {INT a;INT b;} u;")
$tUnion.u.a = 123;
ConsoleWrite($tUnion.u.a&@CRLF); 123
ConsoleWrite($tUnion.u.b&@CRLF); not 123, indicating we read outside the allocated memory space of the struct!