| # Apple notification group |
| |
| **Github Labels:** [O-macos], [O-ios], [O-tvos], [O-watchos] and [O-visionos] <br> |
| **Ping command:** `@rustbot ping apple` |
| |
| This list will be used to ask for help both in diagnosing and testing |
| Apple-related issues as well as suggestions on how to resolve interesting |
| questions regarding our macOS/iOS/tvOS/watchOS/visionOS support. |
| |
| To get a better idea for what the group will do, here are some examples of the |
| kinds of questions where we would have reached out to the group for advice in |
| determining the best course of action: |
| |
| * Raising the minimum supported versions (e.g. [#104385]) |
| * Additional Apple targets (e.g. [#121419]) |
| * Obscure Xcode linker details (e.g. [#121430]) |
| |
| [O-macos]: https://github.com/rust-lang/rust/labels/O-macos |
| [O-ios]: https://github.com/rust-lang/rust/labels/O-ios |
| [O-tvos]: https://github.com/rust-lang/rust/labels/O-tvos |
| [O-watchos]: https://github.com/rust-lang/rust/labels/O-watchos |
| [O-visionos]: https://github.com/rust-lang/rust/labels/O-visionos |
| [#104385]: https://github.com/rust-lang/rust/pull/104385 |
| [#121419]: https://github.com/rust-lang/rust/pull/121419 |
| [#121430]: https://github.com/rust-lang/rust/pull/121430 |
| |
| ## Deployment targets |
| |
| Apple platforms have a concept of "deployment target", controlled with the |
| `*_DEPLOYMENT_TARGET` environment variables, and specifies the minimum OS |
| version that a binary runs on. |
| |
| Using an API from a newer OS version in the standard library than the default |
| that `rustc` uses will result in either a static or a dynamic linker error. |
| For this reason, try to suggest that people document on `extern "C"` APIs |
| which OS version they were introduced with, and if that's newer than the |
| current default used by `rustc`, suggest to use weak linking. |
| |
| ## The App Store and private APIs |
| |
| Apple are very protective about using undocumented APIs, so it's important |
| that whenever a change uses a new function, that they are verified to actually |
| be public API, as even just mentioning undocumented APIs in the binary |
| (without calling it) can lead to rejections from the App Store. |
| |
| For example, Darwin / the XNU kernel actually has futex syscalls, but we can't |
| use them in `std` because they are not public API. |
| |
| In general, for an API to be considered public by Apple, it has to: |
| - Appear in a public header (i.e. one distributed with Xcode, and found for |
| the specific platform under `xcrun --show-sdk-path --sdk $SDK`). |
| - Have an availability attribute on it (like `__API_AVAILABLE`, |
| `API_AVAILABLE` or similar). |
