lib.rs

#[no_mangle]
pub extern "C" fn test() -> int {
  return 1;
}

main.rs

use std::dynamic_lib::DynamicLibrary;
use std::os;

fn print_type_of<T>(_: &T) -> () {
  let type_name =
  unsafe {
    (*std::intrinsics::get_tydesc::<T>()).name
  };
  println!("{}", type_name);
}

fn load_plugin(raw_path: &'static str) {
  let path = Path::new(raw_path);
  let path = os::make_absolute(&path).unwrap();

  let lib = match DynamicLibrary::open(Some(&path)) {
    Ok(lib) => lib,
    Err(error) => panic!("Could not load lib: {}", error)
  };

  let test: *mut fn() -> int = unsafe {
    match lib.symbol::<fn() -> int>("test") {
      Err(error) => panic!("Could not load function: {}", error),
      Ok(test) => test
    }
  };
  
  println!("a");
  print_type_of(&test);
  let c = unsafe {
    (*test)()
  };
  print_type_of(&c);
  println!("Returned: {}", c);
}

fn main() {
    load_plugin("./plugins/plugintest.dll")
}