C99 compilation for iOS (device and simulator)

A way to use C code as a compiled package on iOS.

In a recent project I was faced with the problem of building a library that contained C code (99) that was incompatible with C++ (so I could not easily compile it together with the React Native library code). Hence, after research I added the following flow:

Compiling on iOS the C library -> attaching the compile file to the C++ library for React Native.

Compilation

clang -c -target arm64-apple-ios \
  -isysroot $(xcrun --sdk iphoneos --show-sdk-path) \
  file1.c file2.c file3.c

The next step was to merge the compiled files.

ar rcs lib_arm64.a file1.o file2.o file3.o

If the library is also to run on the simulator on Intel processors, we must also compile for this architecture:

clang -c -target x86_64-apple-ios-simulator \
  -isysroot $(xcrun --sdk iphonesimulator --show-sdk-path) \
  file1.c file2.c file3.c

ar rcs lib_simulator.a file1.o file2.o file3.o

We then combine the result files for both architectures.

lipo -create -output lib_universal.a lib_arm64.a lib_simulator.a

We can include the library prepared in this way, together with the .h files, in our C++ library (e.g. for React Native).