While I sympathize with the aesthetic theme of this post, I warn against the temptation to do what the post proposes, which is to try to compute the checksum of an object represented by void pointer and extent. There are many dangers here, one of which is that the checksum may read uninitialized memory, making the checksum meaningless. Another is that the pointer implicitly converted to void may be a different address depending on the type of the object in the calling function, if the type has multiple base classes. Further, your void reader may be reading derived class data you were unaware of, such that hashing a Base pointer twice yields different results because a member of Derived was placed by the compiler in the tail padding of Base.

In other words, don't do this. C++17 introduced has_unique_object_representations type trait which tells whether it is safe to do this to a given type. It is pretty much always false.