fn main() { println!("{}", unsafe { foo() }); } #[link_name = "foobar"] extern "C" { fn foo() -> u32; }

This fails to link with undefined reference to `foo', but it didn't even try to find any foobar library.

With #[link(name = "foobar")], the error is the expected ld: cannot find -lfoobar.

There are a few places in libstd using #[link_name = "m"] extern {...}, so I wonder if those actually have any effect either.