On Linux, the new <a href="/pkg/syscall#SysProcAttr"><code>SysProcAttr.PidFD</code></a> field allows obtaining a PID FD when starting a child process via <a href="/pkg/syscall#StartProcess"><code>StartProcess</code></a> or <a href="/pkg/os/exec"><code>os/exec</code></a>.
    </p>

    <p><!-- CL 541015 -->

<h3 id="more">Additional Mechanisms</h3>

<p>
The <code>sync</code> package provides additional synchronization abstractions,
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>

which becomes an attribute for all the fields in the corresponding
field declaration. An empty tag string is equivalent to an absent tag.
The tags are made visible through a <a href="/pkg/reflect/#StructTag">reflection interface</a>
and take part in <a href="#Type_identity">type identity</a> for structs
but are otherwise ignored.
</p>

<pre>
struct {

If you want to see what the instructions look like in assembly for a given architecture, say amd64, there
are many examples in the sources of the standard library, in packages such as
<a href="/pkg/runtime/"><code>runtime</code></a> and
<a href="/pkg/math/big/"><code>math/big</code></a>.
You can also examine what the compiler emits as assembly code
(the actual output may differ from what you see here):
</p>

<pre>
$ cat x.go
package main

<small><a href="#" url="https://golang.org/issue">issue</a>,
<a href="#" url="https://golang.org/cl">codereview</a>,
<a href="#" url="https://golang.org/change">commit</a>, or
<a href="#" url="https://golang.org/pkg/">pkg</a> id/name:</small>
<form style='margin: 0' id='navform'><nobr><input id="inputbox" size=10 tabindex=1 /><input type="submit" value="go" /></nobr></form>
<small>Also: <a href="#" url="https://build.golang.org">buildbots</a>

</pre>

Note: This form of conversion may eventually be removed from the language.
The <a href="/pkg/cmd/vet"><code>go vet</code></a> tool flags certain
integer-to-string conversions as potential errors.
Library functions such as
<a href="/pkg/unicode/utf8#AppendRune"><code>utf8.AppendRune</code></a> or
<a href="/pkg/unicode/utf8#EncodeRune"><code>utf8.EncodeRune</code></a>
should be used instead.
</li>
</ol>