- Never hold a reference.
addr_of! lets you get fields of structs without creating an intermediate reference.
- Volatile access: read or write operations may have side-effects, so prevent the compiler or
hardware from reordering, duplicating or eliding them.
- Usually if you write and then read, e.g. via a mutable reference, the compiler may assume that
the value read is the same as the value just written, and not bother actually reading memory.
- Some existing crates for volatile access to hardware do hold references, but this is unsound.
Whenever a reference exist, the compiler may choose to dereference it.
- Use the
addr_of! macro to get struct field pointers from a pointer to the struct.