Behavior considered undefined
Rust code, including within
unsafe blocks and
unsafe functions is incorrect
if it exhibits any of the behaviors in the following list. It is the
programmer's responsibility when writing
unsafe code that it is not possible
safe code exhibit these behaviors.
- Data races.
- Dereferencing a null or dangling raw pointer.
- Unaligned pointer reading and writing outside of
- Reads of undef (uninitialized) memory.
- Breaking the pointer aliasing rules on accesses through raw pointers; a subset of the rules used by C.
&Tfollow LLVM’s scoped noalias model, except if the
- Mutating non-mutable data — that is, data reached through a shared
reference or data owned by a
letbinding), unless that data is contained within an
- Invoking undefined behavior via compiler intrinsics:
- Invalid values in primitive types, even in private fields and locals:
- Dangling or null references and boxes.
- A value other than
1) in a
- A discriminant in an
enumnot included in the type definition.
- A value in a
charwhich is a surrogate or above
- Non-UTF-8 byte sequences in a