<main><divclass="width-limiter"><navclass="sub"><formclass="search-form"><span></span><divid="sidebar-button"tabindex="-1"><ahref="../../tracing_core/all.html"title="show sidebar"></a></div><inputclass="search-input"name="search"aria-label="Run search in the documentation"autocomplete="off"spellcheck="false"placeholder="Click or press ‘S’ to search, ‘?’ for more options…"type="search"><divid="help-button"tabindex="-1"><ahref="../../help.html"title="help">?</a></div><divid="settings-menu"tabindex="-1"><ahref="../../settings.html"title="settings"><imgwidth="22"height="22"alt="Change settings"src="../../static.files/wheel-7b819b6101059cd0.svg"></a></div></form></nav><sectionid="main-content"class="content"><divclass="main-heading"><h1>Struct <ahref="../index.html">tracing_core</a>::<wbr><ahref="index.html">subscriber</a>::<wbr><aclass="struct"href="#">Interest</a><buttonid="copy-path"title="Copy item path to clipboard"><imgsrc="../../static.files/clipboard-7571035ce49a181d.svg"width="19"height="18"alt="Copy item path"></button></h1><spanclass="out-of-band"><aclass="src"href="../../src/tracing_core/subscriber.rs.html#592">source</a> · <buttonid="toggle-all-docs"title="collapse all docs">[<span>−</span>]</button></span></div><preclass="rust item-decl"><code>pub struct Interest(<spanclass="comment">/* private fields */</span>);</code></pre><detailsclass="toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>Indicates a <ahref="../trait.Subscriber.html"title="trait tracing_core::Subscriber"><code>Subscriber</code></a>’s interest in a particular callsite.</p>
<p><code>Subscriber</code>s return an <code>Interest</code> from their <ahref="../trait.Subscriber.html#method.register_callsite"title="method tracing_core::Subscriber::register_callsite"><code>register_callsite</code></a> methods
in order to determine whether that span should be enabled or disabled.</p>
</div></details><h2id="implementations"class="section-header">Implementations<ahref="#implementations"class="anchor">§</a></h2><divid="implementations-list"><detailsclass="toggle implementors-toggle"open><summary><sectionid="impl-Interest"class="impl"><aclass="src rightside"href="../../src/tracing_core/subscriber.rs.html#601-668">source</a><ahref="#impl-Interest"class="anchor">§</a><h3class="code-header">impl <aclass="struct"href="struct.Interest.html"title="struct tracing_core::subscriber::Interest">Interest</a></h3></section></summary><divclass="impl-items"><detailsclass="toggle method-toggle"open><summary><sectionid="method.never"class="method"><aclass="src rightside"href="../../src/tracing_core/subscriber.rs.html#608-610">source</a><h4class="code-header">pub fn <ahref="#method.never"class="fn">never</a>() -> Self</h4></section></summary><divclass="docblock"><p>Returns an <code>Interest</code> indicating that the subscriber is never interested
in being notified about a callsite.</p>
<p>If all active subscribers are <code>never()</code> interested in a callsite, it will
be completely disabled unless a new subscriber becomes active.</p>
</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.sometimes"class="method"><aclass="src rightside"href="../../src/tracing_core/subscriber.rs.html#620-622">source</a><h4class="code-header">pub fn <ahref="#method.sometimes"class="fn">sometimes</a>() -> Self</h4></section></summary><divclass="docblock"><p>Returns an <code>Interest</code> indicating the subscriber is sometimes interested
in being notified about a callsite.</p>
<p>If all active subscribers are <code>sometimes</code> or <code>never</code> interested in a
callsite, the currently active subscriber will be asked to filter that
callsite every time it creates a span. This will be the case until a new
subscriber expresses that it is <code>always</code> interested in the callsite.</p>
</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.always"class="method"><aclass="src rightside"href="../../src/tracing_core/subscriber.rs.html#630-632">source</a><h4class="code-header">pub fn <ahref="#method.always"class="fn">always</a>() -> Self</h4></section></summary><divclass="docblock"><p>Returns an <code>Interest</code> indicating the subscriber is always interested in
being notified about a callsite.</p>
<p>If any subscriber expresses that it is <code>always()</code> interested in a given
callsite, then the callsite will always be enabled.</p>
</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.is_never"class="method"><aclass="src rightside"href="../../src/tracing_core/subscriber.rs.html#637-639">source</a><h4class="code-header">pub fn <ahref="#method.is_never"class="fn">is_never</a>(&self) -><aclass="primitive"href="https://doc.rust-lang.org/1.78.0/std/primitive.bool.html">bool</a></h4></section></summary><divclass="docblock"><p>Returns <code>true</code> if the subscriber is never interested in being notified
</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.is_sometimes"class="method"><aclass="src rightside"href="../../src/tracing_core/subscriber.rs.html#644-646">source</a><h4class="code-header">pub fn <ahref="#method.is_sometimes"class="fn">is_sometimes</a>(&self) -><aclass="primitive"href="https://doc.rust-lang.org/1.78.0/std/primitive.bool.html">bool</a></h4></section></summary><divclass="docblock"><p>Returns <code>true</code> if the subscriber is sometimes interested in being notified
</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.is_always"class="method"><aclass="src rightside"href="../../src/tracing_core/subscriber.rs.html#651-653">source</a><h4class="code-header">pub fn <ahref="#method.is_always"class="fn">is_always</a>(&self) -><aclass="primitive"href="https://doc.rust-lang.org/1.78.0/std/primitive.bool.html">bool</a></h4></section></summary><divclass="docblock"><p>Returns <code>true</code> if the subscriber is always interested in being notified
<code><ahref="https://doc.rust-lang.org/1.78.0/core/convert/trait.From.html"title="trait core::convert::From">From</a><T> for U</code> chooses to do.</p>
</div></details></div></details><detailsclass="toggle implementors-toggle"><summary><sectionid="impl-ToOwned-for-T"class="impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.78.0/src/alloc/borrow.rs.html#83-85">source</a><ahref="#impl-ToOwned-for-T"class="anchor">§</a><h3class="code-header">impl<T><aclass="trait"href="https://doc.rust-lang.org/1.78.0/alloc/borrow/trait.ToOwned.html"title="trait alloc::borrow::ToOwned">ToOwned</a> for T<divclass="where">where
T: <aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/clone/trait.Clone.html"title="trait core::clone::Clone">Clone</a>,</div></h3></section></summary><divclass="impl-items"><detailsclass="toggle"open><summary><sectionid="associatedtype.Owned"class="associatedtype trait-impl"><ahref="#associatedtype.Owned"class="anchor">§</a><h4class="code-header">type <ahref="https://doc.rust-lang.org/1.78.0/alloc/borrow/trait.ToOwned.html#associatedtype.Owned"class="associatedtype">Owned</a> = T</h4></section></summary><divclass='docblock'>The resulting type after obtaining ownership.</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.to_owned"class="method trait-impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.78.0/src/alloc/borrow.rs.html#88">source</a><ahref="#method.to_owned"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.78.0/alloc/borrow/trait.ToOwned.html#tymethod.to_owned"class="fn">to_owned</a>(&self) -> T</h4></section></summary><divclass='docblock'>Creates owned data from borrowed data, usually by cloning. <ahref="https://doc.rust-lang.org/1.78.0/alloc/borrow/trait.ToOwned.html#tymethod.to_owned">Read more</a></div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.clone_into"class="method trait-impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.78.0/src/alloc/borrow.rs.html#92">source</a><ahref="#method.clone_into"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.78.0/alloc/borrow/trait.ToOwned.html#method.clone_into"class="fn">clone_into</a>(&self, target: <aclass="primitive"href="https://doc.rust-lang.org/1.78.0/std/primitive.reference.html">&mut T</a>)</h4></section></summary><divclass='docblock'>Uses borrowed data to replace owned data, usually by cloning. <ahref="https://doc.rust-lang.org/1.78.0/alloc/borrow/trait.ToOwned.html#method.clone_into">Read more</a></div></details></div></details><detailsclass="toggle implementors-toggle"><summary><sectionid="impl-TryFrom%3CU%3E-for-T"class="impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.78.0/src/core/convert/mod.rs.html#805-807">source</a><ahref="#impl-TryFrom%3CU%3E-for-T"class="anchor">§</a><h3class="code-header">impl<T, U><aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><U> for T<divclass="where">where
U: <aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/convert/trait.Into.html"title="trait core::convert::Into">Into</a><T>,</div></h3></section></summary><divclass="impl-items"><detailsclass="toggle"open><summary><sectionid="associatedtype.Error-1"class="associatedtype trait-impl"><ahref="#associatedtype.Error-1"class="anchor">§</a><h4class="code-header">type <ahref="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryFrom.html#associatedtype.Error"class="associatedtype">Error</a> = <aclass="enum"href="https://doc.rust-lang.org/1.78.0/core/convert/enum.Infallible.html"title="enum core::convert::Infallible">Infallible</a></h4></section></summary><divclass='docblock'>The type returned in the event of a conversion error.</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.try_from"class="method trait-impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.78.0/src/core/convert/mod.rs.html#812">source</a><ahref="#method.try_from"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryFrom.html#tymethod.try_from"class="fn">try_from</a>(value: U) -><aclass="enum"href="https://doc.rust-lang.org/1.78.0/core/result/enum.Result.html"title="enum core::result::Result">Result</a><T, <T as <aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><U>>::<aclass="associatedtype"href="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryFrom.html#associatedtype.Error"title="type core::convert::TryFrom::Error">Error</a>></h4></section></summary><divclass='docblock'>Performs the conversion.</div></details></div></details><detailsclass="toggle implementors-toggle"><summary><sectionid="impl-TryInto%3CU%3E-for-T"class="impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.78.0/src/core/convert/mod.rs.html#790-792">source</a><ahref="#impl-TryInto%3CU%3E-for-T"class="anchor">§</a><h3class="code-header">impl<T, U><aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryInto.html"title="trait core::convert::TryInto">TryInto</a><U> for T<divclass="where">where
U: <aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><T>,</div></h3></section></summary><divclass="impl-items"><detailsclass="toggle"open><summary><sectionid="associatedtype.Error"class="associatedtype trait-impl"><ahref="#associatedtype.Error"class="anchor">§</a><h4class="code-header">type <ahref="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryInto.html#associatedtype.Error"class="associatedtype">Error</a> = <U as <aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><T>>::<aclass="associatedtype"href="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryFrom.html#associatedtype.Error"title="type core::convert::TryFrom::Error">Error</a></h4></section></summary><divclass='docblock'>The type returned in the event of a conversion error.</div></details><detailsclass="toggle method-toggle"open><summary><sectionid="method.try_into"class="method trait-impl"><aclass="src rightside"href="https://doc.rust-lang.org/1.78.0/src/core/convert/mod.rs.html#797">source</a><ahref="#method.try_into"class="anchor">§</a><h4class="code-header">fn <ahref="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryInto.html#tymethod.try_into"class="fn">try_into</a>(self) -><aclass="enum"href="https://doc.rust-lang.org/1.78.0/core/result/enum.Result.html"title="enum core::result::Result">Result</a><U, <U as <aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><T>>::<aclass="associatedtype"href="https://doc.rust-lang.org/1.78.0/core/convert/trait.TryFrom.html#associatedtype.Error"title="type core::convert::TryFrom::Error">Error</a>></h4></section></summary><divclass='docblock'>Performs the conversion.</div></details></div></details></div></section></div></main></body></html>
