*-apple-ios

Apple iOS / iPadOS targets.

Tier: 2 (without Host Tools)

• aarch64-apple-ios: Apple iOS on ARM64.
• aarch64-apple-ios-sim: Apple iOS Simulator on ARM64.
• x86_64-apple-ios: Apple iOS Simulator on 64-bit x86.

Tier: 3

• armv7s-apple-ios: Apple iOS on Armv7-A.
• i386-apple-ios: Apple iOS Simulator on 32-bit x86.

Target maintainers

@badboy @deg4uss3r @madsmtm

Requirements

These targets are cross-compiled, and require the corresponding iOS SDK (iPhoneOS.sdk or iPhoneSimulator.sdk), as provided by Xcode. To build the ARM64 targets, Xcode 12 or higher is required.

The path to the SDK can be passed to rustc using the common SDKROOT environment variable, or will be inferred when compiling on host macOS using roughly the same logic as xcrun --sdk iphoneos --show-sdk-path.

OS version

The minimum supported version is iOS 10.0.

This can be raised per-binary by changing the deployment target. rustc respects the common environment variables used by Xcode to do so, in this case IPHONEOS_DEPLOYMENT_TARGET.

Building the target

The tier 2 targets are distributed through rustup, and can be installed using one of:

$ rustup target add aarch64-apple-ios
$ rustup target add aarch64-apple-ios-sim
$ rustup target add x86_64-apple-ios

The tier 3 targets can be built by enabling them for a rustc build in bootstrap.toml, by adding, for example:

[build]
target = ["armv7s-apple-ios", "i386-apple-ios"]

Using the unstable -Zbuild-std with a nightly Cargo may also work.

Building Rust programs

Rust programs can be built for these targets by specifying --target, if rustc has been built with support for them. For example:

$ rustc --target aarch64-apple-ios your-code.rs

Or if using Cargo and -Zbuild-std:

$ cargo +nightly build -Zbuild-std --target armv7s-apple-ios

The simulator variants can be differentiated from the variants running on-device with the target_env = "sim" cfg (or target_abi = "sim" before Rust CURRENT_RUSTC_VERSION).

if cfg!(all(target_vendor = "apple", target_env = "sim")) {
    // Do something on the iOS/tvOS/visionOS/watchOS Simulator.
} else {
    // Everything else, like Windows and non-Simulator iOS.
}

This is similar to the TARGET_OS_SIMULATOR define in C code.

Testing

Running and testing your code naturally requires either an actual device running iOS, or the equivalent Xcode simulator environment. There exists several tools in the ecosystem for running a Cargo project on one of these. One of these tools is cargo-dinghy. madsmtm/objc2#459 contains a more exhaustive list.

See also testing on emulators in the rustc-dev-guide for instructions on running the standard library's test suite.