How to cross-compile protobuf for iOS C++ runtime?

[Arjun Patel]

I have been researching everywhere how to get a simple Qt/C++ project to use protobuf on macOS AND iOS. I need to use protobuf runtime for my app to work, not merely generate C++ headers/source.

For MacOS, I was able to simply download, build, and install grpc and then make my `CMAKE_PREFIX_PATH` point there. This worked as expected.

Of course I got some "wrong architecture" errors when I built for iOS. I still don't quite know how to make this work for iOS. 

I have looked through multiple resources, but they seem outdated:

- https://gist.github.com/BennettSmith/7150245

- https://github.com/sinofool/build-protobuf-ios

- https://stackoverflow.com/questions/19444376/compile-protobuf-with-xcode-5

I am a beginner in the Xcode/Apple as well as C++ in general. So perhaps I am missing some obvious method here.

- Should I be using Xcode to build protobuf from source?

- Should I be cross compiling with some specific cmake instructions, slightly modifying the instructions here in some manner?

Thanks for the help!

Best,

Arjun

[Deanna Garcia]

Thanks for the question! Unfortunately cross-compiling protobuf from source can be pretty difficult (particularly for iOS). Is there a reason you want to build from source instead of just using our pre-built protoc binaries provided in our releases page?

Deanna