Question

 void* GetData()
 {
    return reinterpret_cast<unsigned char*>(this);
 }

Is there a case of automatic type coercion happening in this case ??? How could I convert the object of my class to an unsigned char* ??

Answer 1

I agree with the other posts: this is almost certainly not what you intend to do.

However, IIRC, you are guaranteed by the C++ standard to be able to convert a pointer of any type (not including function or member pointers) to an unsigned char * or a void * and back without entering the realm of undefined behavior. Additionally, you may access any object through an lvalue of type char * or unsigned char * (see ISO 14882:2003 section 3.10.15). I have made use of this before in order to inspect the internal representation of arbitrary object types. This results, if my reading of the standard is correct, in “implementation-defined behavior” (obviously, the internal representation of types depends upon the implementation).

For example,

template<class T> std::vector<unsigned char> to_bytes (const T& t)
{
    const unsigned char *p = reinterpret_cast<const unsigned char *>(&t);
    return std::vector<unsigned char>(p, p + sizeof(T));
}

is a template function that will yield a std::vector<unsigned_char> which is a copy of the object’s internal representation.

However, the fact that you cast to void * when you return makes me suspect you are doing something perhaps more unsavory and more undefined.