Как протащить указатель на функцию из Go в сишную разделяемую библиотеку?

package main

/*
#cgo CFLAGS: -I.
#cgo LDFLAGS: -L. mylib.so

void mylib_init(void *log_f);
void mylib_shutdown();
*/
import "C"

import (
        "log"
        "time"
	"unsafe"
)

func main() {
        logMsg := &logMessage

	C.mylib_init(unsafe.Pointer(logMsg))
	{
		log.Debug("Serving...")

		time.Sleep(5 * time.Second)
	}
	C.mylib_shutdown()
}

// export logMessage
func logMessage(level C.int, message *C.char) {
	switch level {
	case 0:
		log.Error(C.GoString(message))
		break
	case 1:
		log.Warn(C.GoString(message))
		break
	case 2:
		log.Info(C.GoString(message))
		break
	case 3:
		log.Debug(C.GoString(message))
		break
	default:
	}
}

/*
#cgo CFLAGS: -I.
#cgo LDFLAGS: -L. mylib.so

void mylib_init(void *log_f);
void mylib_shutdown();

extern void logMessage(int, char*);
static inline void realInit()
{
    mylib_init(logMessage);
}

*/
import "C"

import (
        "log"
        "time"
        "unsafe"
)

func main() {
        C.realInit()
        {
                log.Debug("Serving...")

                time.Sleep(5 * time.Second)
        }                                                                                                                                                                                                   
        C.mylib_shutdown()                                                                                                                                                                                  
} 

// export logMessage

//export logMessage

use std::ffi::CStr;
use std::os::raw::{c_char, c_int};

type LogFn = extern "C" fn(_: c_int, _: *const c_char);

#[link(name = "my")]
extern "C" {
    fn mylib_init(f: LogFn);
    fn mylib_shutdown();
}

fn main() {
    unsafe { mylib_init(log_message) };

    std::thread::sleep_ms(1000);

    unsafe { mylib_shutdown() };
}

extern "C" fn log_message(level: c_int, message: *const c_char) {
    let msg = unsafe { CStr::from_ptr(message) };
    println!("[{}] {}", level, msg.to_string_lossy());
}