# Extra Clang Tools 7 documentation

## clang-tidy - bugprone-unused-return-value

# bugprone-unused-return-value

Warns on unused function return values. The checked funtions can be configured.

## Options

`CheckedFunctions```

  Semicolon-separated list of functions to check. Defaults to `::std::async;::std::launder;::std::remove;::std::remove_if;::std::unique;::std::unique_ptr::release;::std::basic_string::empty;::std::vector::empty`. This means that the calls to following functions are checked by default:

  - `std::async()`. Not using the return value makes the call synchronous.
  - `std::launder()`. Not using the return value usually means that the function interface was misunderstood by the programmer. Only the returned pointer is “laundered”, not the argument.
  - `std::remove()`, `std::remove_if()` and `std::unique()`. The returned iterator indicates the boundary between elements to keep and elements to be removed. Not using the return value means that the information about which elements to remove is lost.
  - `std::unique_ptr::release()`. Not using the return value can lead to resource leaks if the same pointer isn’t stored anywhere else. Often, ignoring the `release()` return value indicates that the programmer confused the function with `reset()`.
  - `std::basic_string::empty()` and `std::vector::empty()`. Not using the return value often indicates that the programmer confused the function with `clear()`.