Question

How would you convert any struct into byte array on processors with little-endian?

Answer 1

You can use a char* to access any type of object in C++, so:

struct S
{
    int a;
    int b;
    // etc.
};

S my_s;

char* my_s_bytes = reinterpret_cast<char*>(&my_s);

// or, if you prefer static_cast:
char* my_s_bytes = static_cast<char*>(static_cast<void*>(&my_s));

(There is at least some debate over the correctness of the reinterpret_cast vs. the static_cast; in practice it doesn’t really matter–both should yield the same result)