including <a href="/pkg/sync/#Cond">condition variables</a>,
<a href="/pkg/sync/#Map">lock-free maps</a>,
<a href="/pkg/sync/#Pool">allocation pools</a>,
and
<a href="/pkg/sync/#WaitGroup">wait groups</a>.
The documentation for each of these specifies the guarantees it
makes concerning synchronization.
</p>

<p>
Other packages that provide synchronization abstractions

immediately, yielding the element type's <a href="#The_zero_value">zero value</a>
after any previously sent values have been received.
</p>

<pre>
v1 := &lt;-ch
v2 = &lt;-ch
f(&lt;-ch)
&lt;-strobe  // wait until clock pulse and discard received value
</pre>

<p>
A receive expression used in an <a href="#Assignments">assignment</a> or initialization of the special form
</p>

<pre>
x, ok = &lt;-ch

immediately, yielding the element type's <a href="#The_zero_value">zero value</a>
after any previously sent values have been received.
</p>

<pre>
v1 := &lt;-ch
v2 = &lt;-ch
f(&lt;-ch)
&lt;-strobe  // wait until clock pulse and discard received value
</pre>

<p>
A receive expression used in an <a href="#Assignment_statements">assignment statement</a> or initialization of the special form
</p>

<pre>