| Unsafe code was used outside of an unsafe function or block. |
| |
| Erroneous code example: |
| |
| ```compile_fail,E0133 |
| unsafe fn f() { return; } // This is the unsafe code |
| |
| fn main() { |
| f(); // error: call to unsafe function requires unsafe function or block |
| } |
| ``` |
| |
| Using unsafe functionality is potentially dangerous and disallowed by safety |
| checks. Examples: |
| |
| * Dereferencing raw pointers |
| * Calling functions via FFI |
| * Calling functions marked unsafe |
| |
| These safety checks can be relaxed for a section of the code by wrapping the |
| unsafe instructions with an `unsafe` block. For instance: |
| |
| ``` |
| unsafe fn f() { return; } |
| |
| fn main() { |
| unsafe { f(); } // ok! |
| } |
| ``` |
| |
| See the [unsafe section][unsafe-section] of the Book for more details. |
| |
| [unsafe-section]: https://doc.rust-lang.org/book/ch19-01-unsafe-rust.html |
