callbackMutex.Lock()
	callbackToken++
	i := callbackToken
	callbackFuncs[i] = f
	callbackMutex.Unlock()

	// Pass the address of i because the C function was written to
	// take a pointer.  We could pass an int if we felt like
	// rewriting the C code.
	C.callback(unsafe.Pointer(&i))

	callbackMutex.Lock()
	delete(callbackFuncs, i)
	callbackMutex.Unlock()
}

//export goCallback

of an interface type or of elements of a composite type remains unchanged:
</p>

<pre>
// A Mutex is a data type with two methods, Lock and Unlock.
type Mutex struct         { /* Mutex fields */ }
func (m *Mutex) Lock()    { /* Lock implementation */ }
func (m *Mutex) Unlock()  { /* Unlock implementation */ }

// NewMutex has the same composition as Mutex but its method set is empty.
type NewMutex Mutex

pkg syscall (linux-amd64-cgo), type Flock_t struct, Pad_cgo_0 [4]uint8
pkg syscall (linux-amd64-cgo), type Flock_t struct, Pad_cgo_1 [4]uint8
pkg syscall (linux-amd64-cgo), type Flock_t struct, Pid int32
pkg syscall (linux-amd64-cgo), type Flock_t struct, Start int64
pkg syscall (linux-amd64-cgo), type Flock_t struct, Type int16
pkg syscall (linux-amd64-cgo), type Flock_t struct, Whence int16