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<h1 class='fqn'><span class='in-band'>Function <a href='../index.html'>core</a>::<wbr><a href='index.html'>mem</a>::<wbr><a class="fn" href=''>size_of_val</a></span><span class='out-of-band'><span class='since' title='Stable since Rust version 1.0.0'>1.0.0</span><span id='render-detail'>
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<pre class='rust fn'>pub fn size_of_val<T: ?<a class="trait" href="../../core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>>(val: &T) -> usize</pre><div class='docblock'><p>Returns the size of the pointed-to value in bytes.</p>
<p>This is usually the same as <code>size_of::<T>()</code>. However, when <code>T</code> <em>has</em> no
statically known size, e.g. a slice <a href="../../std/primitive.slice.html"><code>[T]</code></a> or a <a href="../../book/first-edition/trait-objects.html">trait object</a>,
then <code>size_of_val</code> can be used to get the dynamically-known size.</p>
<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">mem</span>;
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="number">4</span>, <span class="ident">mem</span>::<span class="ident">size_of_val</span>(<span class="kw-2">&</span><span class="number">5i32</span>));
<span class="kw">let</span> <span class="ident">x</span>: [<span class="ident">u8</span>; <span class="number">13</span>] <span class="op">=</span> [<span class="number">0</span>; <span class="number">13</span>];
<span class="kw">let</span> <span class="ident">y</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>] <span class="op">=</span> <span class="kw-2">&</span><span class="ident">x</span>;
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="number">13</span>, <span class="ident">mem</span>::<span class="ident">size_of_val</span>(<span class="ident">y</span>));<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Amem%3B%0A%0Aassert_eq!(4%2C%20mem%3A%3Asize_of_val(%265i32))%3B%0A%0Alet%20x%3A%20%5Bu8%3B%2013%5D%20%3D%20%5B0%3B%2013%5D%3B%0Alet%20y%3A%20%26%5Bu8%5D%20%3D%20%26x%3B%0Aassert_eq!(13%2C%20mem%3A%3Asize_of_val(y))%3B%0A%7D">Run</a></pre>
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