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<p class='location'>Trait AsPrimitive</p><div class="sidebar-elems"><div class="block items"><a class="sidebar-title" href="#required-methods">Required Methods</a><div class="sidebar-links"><a href="#tymethod.as_">as_</a></div><a class="sidebar-title" href="#foreign-impls">Implementations on Foreign Types</a><div class="sidebar-links"><a href="#impl-AsPrimitive%3Cusize%3E">isize</a><a href="#impl-AsPrimitive%3Ci8%3E">u64</a><a href="#impl-AsPrimitive%3Ci32%3E">i128</a><a href="#impl-AsPrimitive%3Ci64%3E">u128</a><a href="#impl-AsPrimitive%3Cusize%3E">u32</a><a href="#impl-AsPrimitive%3Cisize%3E">i32</a><a href="#impl-AsPrimitive%3Ci128%3E">i64</a><a href="#impl-AsPrimitive%3Ci8%3E">i8</a><a href="#impl-AsPrimitive%3Cu16%3E">i128</a><a href="#impl-AsPrimitive%3Ci128%3E">usize</a><a href="#impl-AsPrimitive%3Cf64%3E">i32</a><a href="#impl-AsPrimitive%3Cu8%3E">char</a><a href="#impl-AsPrimitive%3Ci64%3E">bool</a><a href="#impl-AsPrimitive%3Ci128%3E">u32</a><a href="#impl-AsPrimitive%3Cisize%3E">u32</a><a href="#impl-AsPrimitive%3Cf64%3E">i64</a><a href="#impl-AsPrimitive%3Cu64%3E">i32</a><a href="#impl-AsPrimitive%3Cu64%3E">bool</a><a href="#impl-AsPrimitive%3Ci16%3E">u16</a><a href="#impl-AsPrimitive%3Cu8%3E">i16</a><a href="#impl-AsPrimitive%3Ci128%3E">f32</a><a href="#impl-AsPrimitive%3Cf32%3E">isize</a><a href="#impl-AsPrimitive%3Cusize%3E">i32</a><a href="#impl-AsPrimitive%3Ci64%3E">u8</a><a href="#impl-AsPrimitive%3Ci8%3E">isize</a><a href="#impl-AsPrimitive%3Cu32%3E">i64</a><a href="#impl-AsPrimitive%3Cu64%3E">f32</a><a href="#impl-AsPrimitive%3Cf32%3E">u32</a><a href="#impl-AsPrimitive%3Cu32%3E">f64</a><a href="#impl-AsPrimitive%3Cu8%3E">i32</a><a href="#impl-AsPrimitive%3Ci128%3E">u16</a><a href="#impl-AsPrimitive%3Cisize%3E">i16</a><a href="#impl-AsPrimitive%3Cf64%3E">u32</a><a href="#impl-AsPrimitive%3Ci128%3E">isize</a><a href="#impl-AsPrimitive%3Cf32%3E">i128</a><a href="#impl-AsPrimitive%3Ci8%3E">usize</a><a href="#impl-AsPrimitive%3Cisize%3E">f64</a><a href="#impl-AsPrimitive%3Ci128%3E">i128</a><a href="#impl-AsPrimitive%3Ci16%3E">u32</a><a href="#impl-AsPrimitive%3Cu16%3E">f64</a><a href="#impl-AsPrimitive%3Ci16%3E">u64</a><a href="#impl-AsPrimitive%3Ci16%3E">u128</a><a href="#impl-AsPrimitive%3Cf32%3E">f64</a><a href="#impl-AsPrimitive%3Cu16%3E">i16</a><a href="#impl-AsPrimitive%3Cu64%3E">i8</a><a href="#impl-AsPrimitive%3Cf64%3E">u128</a><a href="#impl-AsPrimitive%3Ci8%3E">f32</a><a href="#impl-AsPrimitive%3Cu128%3E">i8</a><a href="#impl-AsPrimitive%3Ci32%3E">isize</a><a href="#impl-AsPrimitive%3Ci8%3E">char</a><a href="#impl-AsPrimitive%3Cu64%3E">u8</a><a href="#impl-AsPrimitive%3Ci128%3E">i16</a><a href="#impl-AsPrimitive%3Ci64%3E">f32</a><a href="#impl-AsPrimitive%3Cu8%3E">bool</a><a href="#impl-AsPrimitive%3Cusize%3E">u128</a><a href="#impl-AsPrimitive%3Ci8%3E">u16</a><a href="#impl-AsPrimitive%3Cf64%3E">usize</a><a href="#impl-AsPrimitive%3Ci32%3E">usize</a><a href="#impl-AsPrimitive%3Cf32%3E">u16</a><a href="#impl-AsPrimitive%3Cf32%3E">f32</a><a href="#impl-AsPrimitive%3Cu128%3E">u32</a><a href="#impl-AsPrimitive%3Ci64%3E">u16</a><a href="#impl-AsPrimitive%3Cu32%3E">f32</a><a href="#impl-AsPrimitive%3Cisize%3E">u64</a><a href="#impl-AsPrimitive%3Cisize%3E">usize</a><a href="#impl-AsPrimitive%3Cu32%3E">u32</a><a href="#impl-AsPrimitive%3Ci8%3E">i64</a><a href="#impl-AsPrimitive%3Ci32%3E">char</a><a href="#impl-AsPrimitive%3Ci32%3E">i64</a><a href="#impl-AsPrimitive%3Cu128%3E">f64</a><a href="#impl-AsPrimitive%3Ci64%3E">usize</a><a href="#impl-AsPrimitive%3Cu128%3E">u128</a><a href="#impl-AsPrimitive%3Cu32%3E">i32</a><a href="#impl-AsPrimitive%3Ci16%3E">i32</a><a href="#impl-AsPrimitive%3Ci8%3E">i16</a><a href="#impl-AsPrimitive%3Cu128%3E">char</a><a href="#impl-AsPrimitive%3Cchar%3E">u8</a><a href="#impl-AsPrimitive%3Cu64%3E">f64</a><a href="#impl-AsPrimitive%3Cu16%3E">u64</a><a href="#impl-AsPrimitive%3Cu64%3E">u32</a><a href="#impl-AsPrimitive%3Cu8%3E">u128</a><a href="#impl-AsPrimitive%3Cf32%3E">i32</a><a href="#impl-AsPrimitive%3Cu32%3E">u64</a><a href="#impl-AsPrimitive%3Cisize%3E">f32</a
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<section id='main' class="content"><h1 class='fqn'><span class='in-band'>Trait <a href='../index.html'>num_traits</a>::<wbr><a href='index.html'>cast</a>::<wbr><a class="trait" href=''>AsPrimitive</a></span><span class='out-of-band'><span id='render-detail'>
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[<span class='inner'>−</span>]
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</a>
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</span><a class='srclink' href='../../src/num_traits/cast.rs.html#662-668' title='goto source code'>[src]</a></span></h1><div class="docblock type-decl"><pre class='rust trait'>pub trait AsPrimitive<T>: 'static + <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Copy.html" title="trait core::marker::Copy">Copy</a> <span class="where fmt-newline">where<br> T: 'static + <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Copy.html" title="trait core::marker::Copy">Copy</a>, </span>{
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fn <a href='#tymethod.as_' class='fnname'>as_</a>(self) -> T;
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}</pre></div><div class='docblock'><p>A generic interface for casting between machine scalars with the
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<code>as</code> operator, which admits narrowing and precision loss.
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Implementers of this trait AsPrimitive should behave like a primitive
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numeric type (e.g. a newtype around another primitive), and the
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intended conversion must never fail.</p>
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<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
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<pre class="rust rust-example-rendered">
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<span class="kw">let</span> <span class="ident">three</span>: <span class="ident">i32</span> <span class="op">=</span> (<span class="number">3.14159265f32</span>).<span class="ident">as_</span>();
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<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">three</span>, <span class="number">3</span>);</pre>
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<h1 id="safety" class="section-header"><a href="#safety">Safety</a></h1>
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<p>Currently, some uses of the <code>as</code> operator are not entirely safe.
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In particular, it is undefined behavior if:</p>
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<ul>
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<li>A truncated floating point value cannot fit in the target integer
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type (<a href="https://github.com/rust-lang/rust/issues/10184">#10184</a>);</li>
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</ul>
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<div class='information'><div class='tooltip ignore'>ⓘ<span class='tooltiptext'>This example is not tested</span></div></div><pre class="rust rust-example-rendered ignore">
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<span class="kw">let</span> <span class="ident">x</span>: <span class="ident">u8</span> <span class="op">=</span> (<span class="number">1.04E+17</span>).<span class="ident">as_</span>(); <span class="comment">// UB</span></pre>
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<ul>
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<li>Or a floating point value does not fit in another floating
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point type (<a href="https://github.com/rust-lang/rust/issues/15536">#15536</a>).</li>
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</ul>
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<div class='information'><div class='tooltip ignore'>ⓘ<span class='tooltiptext'>This example is not tested</span></div></div><pre class="rust rust-example-rendered ignore">
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<span class="kw">let</span> <span class="ident">x</span>: <span class="ident">f32</span> <span class="op">=</span> (<span class="number">1e300f64</span>).<span class="ident">as_</span>(); <span class="comment">// UB</span></pre>
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</div>
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<h2 id='required-methods' class='small-section-header'>
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Required Methods<a href='#required-methods' class='anchor'></a>
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</h2>
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<div class='methods'>
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<h3 id='tymethod.as_' class='method'><span id='as_.v' class='invisible'><code>fn <a href='#tymethod.as_' class='fnname'>as_</a>(self) -> T</code></span></h3><div class='docblock'><p>Convert a value to another, using the <code>as</code> operator.</p>
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<h3 id='impl-AsPrimitive%3Cusize%3E' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl <a class="trait" href="../../num_traits/cast/trait.AsPrimitive.html" title="trait num_traits::cast::AsPrimitive">AsPrimitive</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>> for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.isize.html">isize</a></code><a href='#impl-AsPrimitive%3Cusize%3E' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/num_traits/cast.rs.html#673-675' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><span class='docblock autohide'><div class='impl-items'><h4 id='method.as_' class="method"><span id='as_.v-1' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='#method.as_' class='fnname'>as_</a>(self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/num_traits/cast.rs.html#674' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4></div></span><h3 id='impl-AsPrimitive%3Ci8%3E' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl <a class="trait" href="../../num_traits/cast/trait.AsPrimitive.html" title="trait num_traits::cast::AsPrimitive">AsPrimitive</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.i8.html">i8</a>> for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.u64.html">u64</a></code><a href='#impl-AsPrimitive%3Ci8%3E' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/num_traits/cast.rs.html#673-675' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><span class='docblock autohide'><div class='impl-items'><h4 id='method.as_-1' class="method"><span id='as_.v-2' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='#method.as_' class='fnname'>as_</a>(self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.i8.html">i8</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/num_traits/cast.rs.html#674' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4></div></span><h3 id='impl-AsPrimitive%3Ci32%3E' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl <a class="trait" href="../../num_traits/cast/trait.AsPrimitive.html" title="trait num_traits::cast::AsPrimitive">AsPrimitive</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.i32.html">i32</a>> for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.i128.html">i128</a></code><a href='#impl-AsPrimitive%3Ci32%3E' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/num_traits/cast.rs.html#673-675' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><span class='docblock autohide'><div class='impl-items'><h4 id='method.as_-2' class="method"><span id='as_.v-3' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='#method.as_' class='fnname'>as_</a>(self) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.i32.html">i32</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/num_traits/cast.rs.html#674' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4></div></span><h3 id='impl-AsPrimitive%3Ci64%3E' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl <a class="trait" href="../../num_traits/cast/trait.AsPrimitive.html" title="trait num_traits::cast::AsPrimitive">AsPrimitiv
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