cgo

package main

import (
   "unsafe"
   "fmt"
)

/*
#cgo CFLAGS: -I./
#cgo LDFLAGS: -L./
#include <test.h>
*/
import "C"

//export println
func println(str *C.char) {
   fmt.Println(C.GoString(str))
}

//export callback
func callback(ptr unsafe.Pointer) {
   f := *(*func(str *C.char))(ptr)
   f(C.CString("Hello,This from Golang"))
}

func main() {
   var fn = println
   C.test(unsafe.Pointer(&fn))
}

/////////////////////////////////

to install TDM-GCC-64

go build

/////////////////test.c///////////

#include <test.h>
int test(void* fn)
{
    callback(fn);
    println("Hello,This from Clang");
    return 0;
}

/////////////test.h////////////

int test(void* fn);
void println(char* str);
void callback(void* fn);