Some linking kinds are target-specific and not supported on all platforms. Linking with `kind=framework` is only supported when targeting macOS, as frameworks are specific to that operating system. Similarly, `kind=raw-dylib` is only supported when targeting Windows-like platforms. Erroneous code example: ```ignore (should-compile_fail-but-cannot-doctest-conditionally-without-macos) #[link(name = "FooCoreServices", kind = "framework")] extern "C" {} // OS used to compile is Linux for example ``` To solve this error you can use conditional compilation: ``` #[cfg_attr(target="macos", link(name = "FooCoreServices", kind = "framework"))] extern "C" {} ``` Learn more in the [Conditional Compilation][conditional-compilation] section of the Reference. [conditional-compilation]: https://doc.rust-lang.org/reference/attributes.html#conditional-compilation