provides facilities for low-level programming including operations
that violate the type system. A package using <code>unsafe</code>
must be vetted manually for type safety and may not be portable.
The package provides the following interface:
</p>

<pre class="grammar">
package unsafe

type ArbitraryType int  // shorthand for an arbitrary Go type; it is not a real type

and of course there is nothing stopping the C code from doing anything
it likes. However, programs that break these rules are likely to fail
in unexpected and unpredictable ways.

The runtime/cgo.Handle type can be used to safely pass Go values
between Go and C. See the runtime/cgo package documentation for details.

Note: the current implementation has a bug. While Go code is permitted

provides facilities for low-level programming including operations
that violate the type system. A package using <code>unsafe</code>
must be vetted manually for type safety and may not be portable.
The package provides the following interface:
</p>

<pre class="grammar">
package unsafe

type ArbitraryType int  // shorthand for an arbitrary Go type; it is not a real type

<code>l.TryLock</code> (or <code>l.TryRLock</code>)
may be considered to be able to return false
even when the mutex <i>l</i> is unlocked.
</p>

<h3 id="once">Once</h3>

<p>
The <code>sync</code> package provides a safe mechanism for
initialization in the presence of multiple goroutines
through the use of the <code>Once</code> type.
Multiple threads can execute <code>once.Do(f)</code> for a particular <code>f</code>,

		pkgCache[key] = pkg
	}

	w.imported[name] = pkg
	return pkg, nil
}

// pushScope enters a new scope (walking a package, type, node, etc)
// and returns a function that will leave the scope (with sanity checking
// for mismatched pushes & pops)
func (w *Walker) pushScope(name string) (popFunc func()) {
	w.scope = append(w.scope, name)
	return func() {
		if len(w.scope) == 0 {

The new [Localize] function safely converts a slash-separated