C callbacks

cb.rs

use core::libc::*;

extern "C"
{
    fn c_func(cb : extern "C" fn(data : *mut c_void), data : *mut c_void);
}

fn rust_func<T>(cb : &fn(data : &T), data : &T)
{
    unsafe
    {
        struct RustData<'self, T>
        {
            Callback : &'self fn(data : &T);
            Data : &'self T;
        }
        
        extern "C"
        fn RustCallback<T>(data : *mut c_void)
        {
            let rust_data : &mut RustData<T> = cast::transmute(data);
            (rust_data.Callback)(rust_data.Data);
        }
        
        let mut rust_data = RustData{Callback : cb, Data : data};
        
        c_func(cast::transmute(RustCallback), cast::transmute(&rust_data));
    }
}