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<a class="header" href="the-doc-attribute.html#the-doc-attribute" id="the-doc-attribute"><h1>The <code>#[doc]</code> attribute</h1></a>
<p>The <code>#[doc]</code> attribute lets you control various aspects of how <code>rustdoc</code> does
its job.</p>
<p>The most basic function of <code>#[doc]</code> is to handle the actual documentation
text. That is, <code>///</code> is syntax sugar for <code>#[doc]</code>. This means that these two
are the same:</p>
<pre><code class="language-rust ignore">/// This is a doc comment.
#[doc = " This is a doc comment."]
</code></pre>
<p>(Note the leading space in the attribute version.)</p>
<p>In most cases, <code>///</code> is easier to use than <code>#[doc]</code>. One case where the latter is easier is
when generating documentation in macros; the <code>collapse-docs</code> pass will combine multiple
<code>#[doc]</code> attributes into a single doc comment, letting you generate code like this:</p>
<pre><code class="language-rust ignore">#[doc = "This is"]
#[doc = " a "]
#[doc = "doc comment"]
</code></pre>
<p>Which can feel more flexible. Note that this would generate this:</p>
<pre><code class="language-rust ignore">#[doc = "This is\n a \ndoc comment"]
</code></pre>
<p>but given that docs are rendered via Markdown, it will remove these newlines.</p>
<p>The <code>doc</code> attribute has more options though! These don't involve the text of
the output, but instead, various aspects of the presentation of the output.
We've split them into two kinds below: attributes that are useful at the
crate level, and ones that are useful at the item level.</p>
<a class="header" href="the-doc-attribute.html#at-the-crate-level" id="at-the-crate-level"><h2>At the crate level</h2></a>
<p>These options control how the docs look at a macro level.</p>
<a class="header" href="the-doc-attribute.html#html_favicon_url" id="html_favicon_url"><h3><code>html_favicon_url</code></h3></a>
<p>This form of the <code>doc</code> attribute lets you control the favicon of your docs.</p>
<pre><code class="language-rust ignore">#![doc(html_favicon_url = "https://example.com/favicon.ico")]
</code></pre>
<p>This will put <code><link rel="shortcut icon" href="{}"></code> into your docs, where
the string for the attribute goes into the <code>{}</code>.</p>
<p>If you don't use this attribute, there will be no favicon.</p>
<a class="header" href="the-doc-attribute.html#html_logo_url" id="html_logo_url"><h3><code>html_logo_url</code></h3></a>
<p>This form of the <code>doc</code> attribute lets you control the logo in the upper
left hand side of the docs.</p>
<pre><code class="language-rust ignore">#![doc(html_logo_url = "https://example.com/logo.jpg")]
</code></pre>
<p>This will put <code><a href='index.html'><img src='{}' alt='logo' width='100'></a></code> into
your docs, where the string for the attribute goes into the <code>{}</code>.</p>
<p>If you don't use this attribute, there will be no logo.</p>
<a class="header" href="the-doc-attribute.html#html_playground_url" id="html_playground_url"><h3><code>html_playground_url</code></h3></a>
<p>This form of the <code>doc</code> attribute lets you control where the "run" buttons
on your documentation examples make requests to.</p>
<pre><code class="language-rust ignore">#![doc(html_playground_url = "https://playground.example.com/")]
</code></pre>
<p>Now, when you press "run", the button will make a request to this domain.</p>
<p>If you don't use this attribute, there will be no run buttons.</p>
<a class="header" href="the-doc-attribute.html#issue_tracker_base_url" id="issue_tracker_base_url"><h3><code>issue_tracker_base_url</code></h3></a>
<p>This form of the <code>doc</code> attribute is mostly only useful for the standard library;
When a feature is unstable, an issue number for tracking the feature must be
given. <code>rustdoc</code> uses this number, plus the base URL given here, to link to
the tracking issue.</p>
<pre><code class="language-rust ignore">#![doc(issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/")]
</code></pre>
<a class="header" href="the-doc-attribute.html#html_no_source" id="html_no_source"><h3><code>html_no_source</code></h3></a>
<p>By default, <code>rustdoc</code> will include the source code of your program, with links
to it in the docs. But if you include this:</p>
<pre><code class="language-rust ignore">#![doc(html_no_source)]
</code></pre>
<p>it will not.</p>
<a class="header" href="the-doc-attribute.html#testno_crate_inject" id="testno_crate_inject"><h3><code>test(no_crate_inject)</code></h3></a>
<p>By default, <code>rustdoc</code> will automatically add a line with <code>extern crate my_crate;</code> into each doctest.
But if you include this:</p>
<pre><code class="language-rust ignore">#![doc(test(no_crate_inject))]
</code></pre>
<p>it will not.</p>
<a class="header" href="the-doc-attribute.html#testattr" id="testattr"><h3><code>test(attr(...))</code></h3></a>
<p>This form of the <code>doc</code> attribute allows you to add arbitrary attributes to all your doctests. For
example, if you want your doctests to fail if they produce any warnings, you could add this:</p>
<pre><code class="language-rust ignore">#![doc(test(attr(deny(warnings))))]
</code></pre>
<a class="header" href="the-doc-attribute.html#at-the-item-level" id="at-the-item-level"><h2>At the item level</h2></a>
<p>These forms of the <code>#[doc]</code> attribute are used on individual items, to control how
they are documented.</p>
<a class="header" href="the-doc-attribute.html#docno_inlinedocinline" id="docno_inlinedocinline"><h2><code>#[doc(no_inline)]</code>/<code>#[doc(inline)]</code></h2></a>
<p>These attributes are used on <code>use</code> statements, and control where the documentation shows
up. For example, consider this Rust code:</p>
<pre><code class="language-rust ignore">pub use bar::Bar;
/// bar docs
pub mod bar {
/// the docs for Bar
pub struct Bar;
}
</code></pre>
<p>The documentation will generate a "Re-exports" section, and say <code>pub use bar::Bar;</code>, where
<code>Bar</code> is a link to its page.</p>
<p>If we change the <code>use</code> line like this:</p>
<pre><code class="language-rust ignore">#[doc(inline)]
pub use bar::Bar;
</code></pre>
<p>Instead, <code>Bar</code> will appear in a <code>Structs</code> section, just like <code>Bar</code> was defined at the
top level, rather than <code>pub use</code>'d.</p>
<p>Let's change our original example, by making <code>bar</code> private:</p>
<pre><code class="language-rust ignore">pub use bar::Bar;
/// bar docs
mod bar {
/// the docs for Bar
pub struct Bar;
}
</code></pre>
<p>Here, because <code>bar</code> is not public, <code>Bar</code> wouldn't have its own page, so there's nowhere
to link to. <code>rustdoc</code> will inline these definitions, and so we end up in the same case
as the <code>#[doc(inline)]</code> above; <code>Bar</code> is in a <code>Structs</code> section, as if it were defined at
the top level. If we add the <code>no_inline</code> form of the attribute:</p>
<pre><code class="language-rust ignore">#[doc(no_inline)]
pub use bar::Bar;
/// bar docs
mod bar {
/// the docs for Bar
pub struct Bar;
}
</code></pre>
<p>Now we'll have a <code>Re-exports</code> line, and <code>Bar</code> will not link to anywhere.</p>
<a class="header" href="the-doc-attribute.html#dochidden" id="dochidden"><h2><code>#[doc(hidden)]</code></h2></a>
<p>Any item annotated with <code>#[doc(hidden)]</code> will not appear in the documentation, unless
the <code>strip-hidden</code> pass is removed.</p>
<a class="header" href="the-doc-attribute.html#docprimitive" id="docprimitive"><h2><code>#[doc(primitive)]</code></h2></a>
<p>Since primitive types are defined in the compiler, there's no place to attach documentation
attributes. This attribute is used by the standard library to provide a way to generate
documentation for primitive types.</p>
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