How to cross compile from Mac to Linux?

Question

I wrote a little game using Rust, and I used cargo build --release to compile a release version on Mac.

I tried to share this with my friend who is using Ubuntu, but when he tried to run the binary, he got the following error:

cannot execute binary file: Exec format error

I searched for this but found no answers. Doesn't Rust claim to have "no runtime"? Shouldn't it be able to run anywhere in binary form?

Answer 1

Well, it is because Rust has no runtime (unlike e.g. Java's JVM) that you can't just compile code on one OS and expect it to run on a different one; what you are looking for is cross-compilation. I haven't done it in Rust, but from what I can gather you can find relevant information on different cross-compilation Rust strategies on this GitHub repo.

Answer 2

Rust not having a runtime means that it doesn't have a lot of code running as part of the language (for example a garbage collector or bytecode interpreter). It does still need to use operating system primitives (i.e. syscalls), and these are different on MacOS and Linux.

What you want is a cross compiler. If you're using rustup, then installing a cross compiler should be simple:

# Install the toolchain to build Linux x86_64 binaries
rustup target add x86_64-unknown-linux-gnu

Then building is:

cargo build --release --target=x86_64-unknown-linux-gnu

Caveat: I don't have an OS X machine to test this on; please comment or edit to fix this if it works!