<p>
A <code>Pointer</code> is a <a href="#Pointer_types">pointer type</a> but a <code>Pointer</code>
value may not be <a href="#Address_operators">dereferenced</a>.
Any pointer or value of <a href="#Types">underlying type</a> <code>uintptr</code> can be converted to
a type of underlying type <code>Pointer</code> and vice versa.
The effect of converting between <code>Pointer</code> and <code>uintptr</code> is implementation-defined.
</p>

	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
func goCallback(p unsafe.Pointer) {
	i := *(*int)(p)

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