Rosetta

Rosetta 2 lets Apple Silicon Macs run x86_64 binaries by translating them at launch. Universal binaries bundle both architectures; other tools need to be told explicitly to target x86_64 so Rosetta can run the result.

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Run a Specific Architecture from a Universal Binary

arch -x86_64 <command> re-executes <command> under the x86_64 slice of a universal binary instead of the native arm64 one.

Compile C/C++ for x86_64

• clang/gcc directly: add -target x86_64-apple-darwin to the compile command.
• CMake: set CMAKE_OSX_ARCHITECTURES at configure time.

The resulting binary runs under Rosetta on Apple Silicon.

Compile Rust for x86_64

Add the target once, then build against it explicitly.

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Cheatsheet

Run a Specific Architecture

arch -x86_64 <command>

Compile C/C++ for x86_64

# clang/gcc
clang -target x86_64-apple-darwin <source.c> -o <binary>
 
# CMake
cmake -S . -B build -DCMAKE_OSX_ARCHITECTURES=x86_64
cmake --build build

Compile Rust for x86_64

rustup target add x86_64-apple-darwin
cargo build --target x86_64-apple-darwin