"unsafe"
)

// Pass a func value from nestedCall to goCallback using an integer token.
var callbackMutex sync.Mutex
var callbackToken int
var callbackFuncs = make(map[int]func())

// nestedCall calls into C, back into Go, and finally to f.
func nestedCall(f func()) {
	// callback(x) calls goCallback(x)
	callbackMutex.Lock()
	callbackToken++
	i := callbackToken
	callbackFuncs[i] = f
	callbackMutex.Unlock()

raw string literals and interpreted string literals.
</p>

<p>
Raw string literals are character sequences between back quotes, as in
<code>`foo`</code>.  Within the quotes, any character may appear except
back quote. The value of a raw string literal is the
string composed of the uninterpreted (implicitly UTF-8-encoded) characters
between the quotes;