void* or char* for generic buffer representation?
For the constructor and other API functions, the advantage of void* is that it allows the caller to pass in a pointer to any type without having to do an unnecessary cast. If it makes sense for the caller to be able to pass in any type, then void* is preferable. If it really only makes sense for the caller to be able to pass in char*, then use that type.
C++17
C++17 introduced std::byte specifically for this.
Its definition is actually simple: enum class byte : unsigned char {};.
I generally used unsigned char as the underlying structure (don't want signedness to mess up with my buffer for I know what reason). However I usually typedefed it:
// C++11using byte = unsigned char;// C++98typedef unsigned char byte;And then refer to it as byte* which neatly conveys the meaning in my opinion, better than either char* or void* at least.