mentat/docs/apis/rust/scoped_tls/struct.ScopedKey.html
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<p class='location'>Struct ScopedKey</p><div class="sidebar-elems"><div class="block items"><a class="sidebar-title" href="#methods">Methods</a><div class="sidebar-links"><a href="#method.set">set</a><a href="#method.with">with</a><a href="#method.is_set">is_set</a></div><a class="sidebar-title" href="#implementations">Trait Implementations</a><div class="sidebar-links"><a href="#impl-Sync">Sync</a></div><a class="sidebar-title" href="#synthetic-implementations">Auto Trait Implementations</a><div class="sidebar-links"><a href="#impl-Send">Send</a></div></div><p class='location'><a href='index.html'>scoped_tls</a></p><script>window.sidebarCurrent = {name: 'ScopedKey', ty: 'struct', relpath: ''};</script><script defer src="sidebar-items.js"></script></div>
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<section id='main' class="content"><h1 class='fqn'><span class='in-band'>Struct <a href='index.html'>scoped_tls</a>::<wbr><a class="struct" href=''>ScopedKey</a></span><span class='out-of-band'><span id='render-detail'>
<a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">
[<span class='inner'>&#x2212;</span>]
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</span><a class='srclink' href='../src/scoped_tls/lib.rs.html#94-99' title='goto source code'>[src]</a></span></h1><div class="docblock type-decl"><pre class='rust struct'>pub struct ScopedKey&lt;T&gt; { /* fields omitted */ }</pre></div><div class='docblock'><p>Type representing a thread local storage key corresponding to a reference
to the type parameter <code>T</code>.</p>
<p>Keys are statically allocated and can contain a reference to an instance of
type <code>T</code> scoped to a particular lifetime. Keys provides two methods, <code>set</code>
and <code>with</code>, both of which currently use closures to control the scope of
their contents.</p>
</div>
<h2 id='methods' class='small-section-header'>
Methods<a href='#methods' class='anchor'></a>
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<h3 id='impl' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl&lt;T&gt; <a class="struct" href="../scoped_tls/struct.ScopedKey.html" title="struct scoped_tls::ScopedKey">ScopedKey</a>&lt;T&gt;</code><a href='#impl' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/scoped_tls/lib.rs.html#103-197' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.set' class="method"><span id='set.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.set' class='fnname'>set</a>&lt;F, R&gt;(&amp;'static self, t: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;</a>T, f: F) -&gt; R <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;F: <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/function/trait.FnOnce.html" title="trait core::ops::function::FnOnce">FnOnce</a>() -&gt; R,&nbsp;</span></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/scoped_tls/lib.rs.html#137-156' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Inserts a value into this scoped thread local storage slot for a
duration of a closure.</p>
<p>While <code>cb</code> is running, the value <code>t</code> will be returned by <code>get</code> unless
this function is called recursively inside of <code>cb</code>.</p>
<p>Upon return, this function will restore the previous value, if any
was available.</p>
<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="attribute">#[<span class="ident">macro_use</span>]</span>
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">scoped_tls</span>;
<span class="macro">scoped_thread_local</span><span class="macro">!</span>(<span class="kw">static</span> <span class="ident">FOO</span>: <span class="ident">u32</span>);
<span class="ident">FOO</span>.<span class="ident">set</span>(<span class="kw-2">&amp;</span><span class="number">100</span>, <span class="op">||</span> {
<span class="kw">let</span> <span class="ident">val</span> <span class="op">=</span> <span class="ident">FOO</span>.<span class="ident">with</span>(<span class="op">|</span><span class="ident">v</span><span class="op">|</span> <span class="kw-2">*</span><span class="ident">v</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">val</span>, <span class="number">100</span>);
<span class="comment">// set can be called recursively</span>
<span class="ident">FOO</span>.<span class="ident">set</span>(<span class="kw-2">&amp;</span><span class="number">101</span>, <span class="op">||</span> {
<span class="comment">// ...</span>
});
<span class="comment">// Recursive calls restore the previous value.</span>
<span class="kw">let</span> <span class="ident">val</span> <span class="op">=</span> <span class="ident">FOO</span>.<span class="ident">with</span>(<span class="op">|</span><span class="ident">v</span><span class="op">|</span> <span class="kw-2">*</span><span class="ident">v</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">val</span>, <span class="number">100</span>);
});</pre>
</div><h4 id='method.with' class="method"><span id='with.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.with' class='fnname'>with</a>&lt;F, R&gt;(&amp;'static self, f: F) -&gt; R <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;F: <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/function/trait.FnOnce.html" title="trait core::ops::function::FnOnce">FnOnce</a>(<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;</a>T) -&gt; R,&nbsp;</span></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/scoped_tls/lib.rs.html#182-191' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Gets a value out of this scoped variable.</p>
<p>This function takes a closure which receives the value of this
variable.</p>
<h1 id="panics" class="section-header"><a href="#panics">Panics</a></h1>
<p>This function will panic if <code>set</code> has not previously been called.</p>
<h1 id="examples-1" class="section-header"><a href="#examples-1">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="attribute">#[<span class="ident">macro_use</span>]</span>
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">scoped_tls</span>;
<span class="macro">scoped_thread_local</span><span class="macro">!</span>(<span class="kw">static</span> <span class="ident">FOO</span>: <span class="ident">u32</span>);
<span class="ident">FOO</span>.<span class="ident">with</span>(<span class="op">|</span><span class="ident">slot</span><span class="op">|</span> {
<span class="comment">// work with `slot`</span>
});</pre>
</div><h4 id='method.is_set' class="method"><span id='is_set.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.is_set' class='fnname'>is_set</a>(&amp;'static self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/scoped_tls/lib.rs.html#194-196' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Test whether this TLS key has been <code>set</code> for the current thread.</p>
</div></div>
<h2 id='implementations' class='small-section-header'>
Trait Implementations<a href='#implementations' class='anchor'></a>
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<h3 id='impl-Sync' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sync.html" title="trait core::marker::Sync">Sync</a> for <a class="struct" href="../scoped_tls/struct.ScopedKey.html" title="struct scoped_tls::ScopedKey">ScopedKey</a>&lt;T&gt;</code><a href='#impl-Sync' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../src/scoped_tls/lib.rs.html#101' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'></div></div>
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Auto Trait Implementations<a href='#synthetic-implementations' class='anchor'></a>
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<h3 id='impl-Send' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a> for <a class="struct" href="../scoped_tls/struct.ScopedKey.html" title="struct scoped_tls::ScopedKey">ScopedKey</a>&lt;T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a>,&nbsp;</span></code><a href='#impl-Send' class='anchor'></a></span></td><td><span class='out-of-band'></span></td></tr></tbody></table></h3><div class='impl-items'></div></div></section>
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