| r[safety] |
| # Unsafety |
| |
| r[safety.intro] |
| Unsafe operations are those that can potentially violate the memory-safety |
| guarantees of Rust's static semantics. |
| |
| r[safety.unsafe-ops] |
| The following language level features cannot be used in the safe subset of |
| Rust: |
| |
| r[safety.unsafe-deref] |
| - Dereferencing a [raw pointer]. |
| |
| r[safety.unsafe-static] |
| - Reading or writing a [mutable] or [external] static variable. |
| |
| r[safety.unsafe-union-access] |
| - Accessing a field of a [`union`], other than to assign to it. |
| |
| r[safety.unsafe-call] |
| - Calling an unsafe function (including an intrinsic or foreign function). |
| |
| r[safety.unsafe-target-feature-call] |
| - Calling a safe function marked with a [`target_feature`][attributes.codegen.target_feature] from a function that does not have a `target_feature` attribute enabling the same features (see [attributes.codegen.target_feature.safety-restrictions]). |
| |
| r[safety.unsafe-impl] |
| - Implementing an [unsafe trait]. |
| |
| r[safety.unsafe-extern] |
| - Declaring an [`extern`] block[^extern-2024]. |
| |
| r[safety.unsafe-attribute] |
| - Applying an [unsafe attribute] to an item. |
| |
| [^extern-2024]: Prior to the 2024 edition, extern blocks were allowed to be declared without `unsafe`. |
| |
| [`extern`]: items/external-blocks.md |
| [`union`]: items/unions.md |
| [mutable]: items/static-items.md#mutable-statics |
| [external]: items/external-blocks.md |
| [raw pointer]: types/pointer.md |
| [unsafe trait]: items/traits.md#unsafe-traits |
| [unsafe attribute]: attributes.md |
