Say that `const extern` functions can only use "Rust" or "C"
@@ -216,6 +216,8 @@ Functions qualified with the `const` keyword are [const functions], as are
[tuple struct] and [tuple variant] constructors. _Const functions_ can be
called from within [const contexts].
+Const functions may use the [`extern`] function qualifier, but only with the `"Rust"` and `"C"` ABIs.
+
Const functions are not allowed to be [async](#async-functions).
## Async functions
@@ -382,6 +384,7 @@ fn foo_oof(#[some_inert_attribute] arg: u8) {
[const functions]: ../const_eval.md#const-functions
[tuple struct]: structs.md
[tuple variant]: enumerations.md
+[`extern`]: #extern-function-qualifier
[external block]: external-blocks.md
[path]: ../paths.md
[block]: ../expressions/block-expr.md
