https://stackoverflow.com/questions/65229930/is-it-possible-to-call-a-function-from-static-library-that-built-in-rust-using-c

• cargo new rustutils --lib

• Cargo.toml

   [lib]
   crate-type = ["cdylib"]      # dynamic lib
   # crate-type = ["staticlib"] # static lib
  

• Add a C API

   #[no_mangle]
   pub extern "C" fn message() {
     println!("Hello C!")
   }
  

• Build

   cargo build --release
  

• Generate C header file

   cargo install cbindgen
   touch cbindgen.toml
   cbindgen --config cbindgen.toml --crate rustutils  --output rustutils.h --lang c
  

• Compile C example

  Move rustutils.h and librustutils.a to examples folder

  cd example
  gcc main.c -L. -lrustutils -o main