For example, the <code>twoprint</code> program might be
incorrectly written as:
</p>

<pre>
var a string
var done bool

func setup() {
	a = "hello, world"
	done = true
}

func doprint() {
	if !done {
		once.Do(setup)
	}
	print(a)
}

func twoprint() {
	go doprint()
	go doprint()
}
</pre>

<p>

  <dd>
    <p><!-- https://go.dev/issue/61827, CL 517777 -->
      The <a href="/pkg/reflect/#Value.IsZero"><code>Value.IsZero</code></a>
      method will now return true for a floating-point or complex
      negative zero, and will return true for a struct value if a
      blank field (a field named <code>_</code>) somehow has a
      non-zero value.
      These changes make <code>IsZero</code> consistent with comparing

are still treated specially;
for instance, references to <code>SP</code> require a symbol,
much like <code>FP</code>.
To access the actual hardware register use the true <code>R</code> name.
For example, on the ARM architecture the hardware
<code>SP</code> and <code>PC</code> are accessible as
<code>R13</code> and <code>R15</code>.
</p>

<p>