gistfile1.txt

doug:rust-libs doug$ cat junk.rs
#![crate_id = "junk#0.1"]
use std::libc::c_int;

#[no_mangle]
pub extern fn dothing(a: c_int, b:c_int) -> c_int {
  return a + b;
}

gistfile2.txt

doug:rust-libs doug$ rustc --crate-type=dylib junk.rs
doug:rust-libs doug$ ls
README.md                  junk.rs                    libjunk-7ac869a1-0.1.rlib  main.rs
doc                        libjunk-7ac869a1-0.1.dylib main
doug:rust-libs doug$ python
Python 2.7.6 (default, Nov 20 2013, 09:06:02)
[GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.2.79)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import ctypes
>>> lib = ctypes.CDLL("libjunk-7ac869a1-0.1.dylib")
>>> lib
<CDLL 'libjunk-7ac869a1-0.1.dylib', handle 7ff4c3718fd0 at 101aa1a90>
>>> lib.dothing(1, 2)
3
>>>