Annotating types with #[must-use]

bindgen can be instructed to annotate certain types with #[must_use].

Some libraries have a common error type, returned by lots of their functions, which needs to be checked after every call. In these cases it's useful to add #[must_use] to this type, so the Rust compiler emits a warning when the check is missing.

Library

• bindgen::Builder::must_use_type

Command Line

• --must-use-type <regex>

Annotations

/** <div rustbindgen mustusetype></div> */
struct ErrorType {
    // ...
};

...