This option is tricky but possible on Android, but it’s impossible on iOS. There is no such thing as stdin/stdout communication on iOS. You can’t in fact ship more than one executable. Everything has to be one big statically linked object file. You can checkout the port of the beam, but in short the system() and spawn_port() commands are not supported on iOS. This is an iOS limitation and intended by apple.

For that reason I went with JSON communication via sockets. But it’s all running in the same iOS process. With some more native plumbing the socket could be replaced with in-process communication with memory buffers which would be more efficient, but I didn’t have enough time for that.

I knew the IOS is locked down; I didn’t know it is this locked down. Thanks!

Ping to @dominicletz (the author).

For example the Mozilla foundation uses UniFFI to help with the generation of the bindings to include Rust in their SDKs for Android, iOS and others:

UniFFI is a tool that automatically generates foreign-language bindings targeting Rust libraries.
It fits in the practice of consolidating business logic in a single Rust library while targeting multiple platforms, making it simpler to develop and maintain a cross-platform codebase.
Note that this tool will not help you ship a Rust library to these platforms, but simply not have to write bindings code by hand

I still need to find resources on how to compile to iOS and Android.