Is reinterpret_cast mostly useless?

Question

I\'ve read various previous questions about the use of reinterpret_cast, and I\'ve also read the relevant wording in the C++ standard. Essentially, what it comes down to is

Answer 1

there's no guarantee that a reinterpret_cast from char* to unsigned char* won't crash your program when you try to dereference the unsigned char* pointer.

You can't do such a cast in any other way, so you have to have to trust what your compiler does with this completely reasonable cast.

Since reinterpret_cast doesn't seem to guarantee this actually works, are C-style casts the only safe option here?

The C-style cast will just map to reinterpret_cast so it will be exactly the same. At some point you have to trust your compiler. The Standard has a limit on which it simply says "no. read your compiler's manual". When it comes to cross-casting pointers, this is such a point. It allows you to read a char using an unsigned char lvalue. A compiler that cannot cast a char* to a usable unsigned char* to do such is just about unusable and doesn't exist for that reason.