diff --git a/src/doc/rustdoc/src/unstable-features.md b/src/doc/rustdoc/src/unstable-features.md index c7fd5ed6fcb2..141d5d2d2b2d 100644 --- a/src/doc/rustdoc/src/unstable-features.md +++ b/src/doc/rustdoc/src/unstable-features.md @@ -512,3 +512,17 @@ crate being documented (`foobar`) and a path to output the calls To scrape examples from test code, e.g. functions marked `#[test]`, then add the `--scrape-tests` flag. + +### `--check-cfg`: check configuration flags + +This flag accepts the same values as `rustc --check-cfg`, and uses it to check configuration flags. + +Using this flag looks like this: + +```bash +$ rustdoc src/lib.rs -Z unstable-options \ + --check-cfg='names()' --check-cfg='values(feature, "foo", "bar")' +``` + +The example above check every well known names (`target_os`, `doc`, `test`, ... via `names()`) +and check the values of `feature`: `foo` and `bar`.