<p>
For example, in this program:
</p>

<pre>
var a string

func f() {
	print(a)
}

func hello() {
	a = "hello, world"
	go f()
}
</pre>

<p>
calling <code>hello</code> will print <code>"hello, world"</code>
at some point in the future (perhaps after <code>hello</code> has returned).
</p>

<h3 id="goexit">Goroutine destruction</h3>

<p>

var b = make([]byte, 5)
n1 := copy(s, a[0:])            // n1 == 6, s == []int{0, 1, 2, 3, 4, 5}
n2 := copy(s, s[2:])            // n2 == 4, s == []int{2, 3, 4, 5, 4, 5}
n3 := copy(b, "Hello, World!")  // n3 == 5, b == []byte("Hello")
</pre>


<h3 id="Deletion_of_map_elements">Deletion of map elements</h3>

<p>
The built-in function <code>delete</code> removes the element with key

var b = make([]byte, 5)
n1 := copy(s, a[0:])            // n1 == 6, s is []int{0, 1, 2, 3, 4, 5}
n2 := copy(s, s[2:])            // n2 == 4, s is []int{2, 3, 4, 5, 4, 5}
n3 := copy(b, "Hello, World!")  // n3 == 5, b is []byte("Hello")
</pre>


<h3 id="Clear">Clear</h3>

<p>
The built-in function <code>clear</code> takes an argument of <a href="#Map_types">map</a>,