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<section id='main' class="content struct">
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<h1 class='fqn'><span class='in-band'>Struct <a href='../../index.html'>bitflags</a>::<wbr><a href='../index.html'>__core</a>::<wbr><a href='index.html'>sync</a>::<wbr><a class='struct' href=''>RwLock</a></span><span class='out-of-band'><span id='render-detail'>
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[<span class='inner'>−</span>]
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</span><a id='src-10293' class='srclink' href='https://doc.rust-lang.org/nightly/std/sync/rwlock/struct.RwLock.html?gotosrc=10293' title='goto source code'>[src]</a></span></h1>
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<pre class='rust struct'>pub struct RwLock<T> <span class='where'>where T: ?<a class='trait' href='../../../bitflags/__core/marker/trait.Sized.html' title='bitflags::__core::marker::Sized'>Sized</a></span> {
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// some fields omitted
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}</pre><span class="since">1.0.0</span><div class='docblock'><p>A reader-writer lock</p>
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<p>This type of lock allows a number of readers or at most one writer at any
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point in time. The write portion of this lock typically allows modification
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of the underlying data (exclusive access) and the read portion of this lock
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typically allows for read-only access (shared access).</p>
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<p>The priority policy of the lock is dependent on the underlying operating
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system's implementation, and this type does not guarantee that any
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particular policy will be used.</p>
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<p>The type parameter <code>T</code> represents the data that this lock protects. It is
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required that <code>T</code> satisfies <code>Send</code> to be shared across threads and <code>Sync</code> to
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allow concurrent access through readers. The RAII guards returned from the
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locking methods implement <code>Deref</code> (and <code>DerefMut</code> for the <code>write</code> methods)
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to allow access to the contained of the lock.</p>
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<h1 id='poisoning' class='section-header'><a href='#poisoning'>Poisoning</a></h1>
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<p>RwLocks, like Mutexes, will become poisoned on panics. Note, however, that
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an RwLock may only be poisoned if a panic occurs while it is locked
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exclusively (write mode). If a panic occurs in any reader, then the lock
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will not be poisoned.</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'>use</span> <span class='ident'>std</span>::<span class='ident'>sync</span>::<span class='ident'>RwLock</span>;
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<span class='kw'>let</span> <span class='ident'>lock</span> <span class='op'>=</span> <span class='ident'>RwLock</span>::<span class='ident'>new</span>(<span class='number'>5</span>);
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<span class='comment'>// many reader locks can be held at once</span>
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{
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<span class='kw'>let</span> <span class='ident'>r1</span> <span class='op'>=</span> <span class='ident'>lock</span>.<span class='ident'>read</span>().<span class='ident'>unwrap</span>();
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<span class='kw'>let</span> <span class='ident'>r2</span> <span class='op'>=</span> <span class='ident'>lock</span>.<span class='ident'>read</span>().<span class='ident'>unwrap</span>();
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<span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='op'>*</span><span class='ident'>r1</span>, <span class='number'>5</span>);
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<span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='op'>*</span><span class='ident'>r2</span>, <span class='number'>5</span>);
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} <span class='comment'>// read locks are dropped at this point</span>
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<span class='comment'>// only one write lock may be held, however</span>
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{
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<span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>w</span> <span class='op'>=</span> <span class='ident'>lock</span>.<span class='ident'>write</span>().<span class='ident'>unwrap</span>();
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<span class='op'>*</span><span class='ident'>w</span> <span class='op'>+=</span> <span class='number'>1</span>;
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<span class='macro'>assert_eq</span><span class='macro'>!</span>(<span class='op'>*</span><span class='ident'>w</span>, <span class='number'>6</span>);
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} <span class='comment'>// write lock is dropped here</span></pre>
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</div><h2 id='methods'>Methods</h2><h3 class='impl'><code>impl<T> <a class='struct' href='../../../bitflags/__core/sync/struct.RwLock.html' title='bitflags::__core::sync::RwLock'>RwLock</a><T></code></h3><div class='impl-items'><h4 id='method.new' class='method'><code>fn <a href='#method.new' class='fnname'>new</a>(t: T) -> <a class='struct' href='../../../bitflags/__core/sync/struct.RwLock.html' title='bitflags::__core::sync::RwLock'>RwLock</a><T></code></h4>
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<div class='docblock'><p>Creates a new instance of an <code>RwLock<T></code> which is unlocked.</p>
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<h1 id='examples-1' class='section-header'><a href='#examples-1'>Examples</a></h1>
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<pre class='rust rust-example-rendered'>
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<span class='kw'>use</span> <span class='ident'>std</span>::<span class='ident'>sync</span>::<span class='ident'>RwLock</span>;
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<span class='kw'>let</span> <span class='ident'>lock</span> <span class='op'>=</span> <span class='ident'>RwLock</span>::<span class='ident'>new</span>(<span class='number'>5</span>);</pre>
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</div></div><h3 class='impl'><code>impl<T> <a class='struct' href='../../../bitflags/__core/sync/struct.RwLock.html' title='bitflags::__core::sync::RwLock'>RwLock</a><T> <span class='where'>where T: ?<a class='trait' href='../../../bitflags/__core/marker/trait.Sized.html' title='bitflags::__core::marker::Sized'>Sized</a></span></code></h3><div class='impl-items'><h4 id='method.read' class='method'><code>fn <a href='#method.read' class='fnname'>read</a>(&self) -> <a class='enum' href='../../../bitflags/__core/result/enum.Result.html' title='bitflags::__core::result::Result'>Result</a><<a class='struct' href='../../../bitflags/__core/sync/struct.RwLockReadGuard.html' title='bitflags::__core::sync::RwLockReadGuard'>RwLockReadGuard</a><T>, <a class='struct' href='../../../bitflags/__core/sync/struct.PoisonError.html' title='bitflags::__core::sync::PoisonError'>PoisonError</a><<a class='struct' href='../../../bitflags/__core/sync/struct.RwLockReadGuard.html' title='bitflags::__core::sync::RwLockReadGuard'>RwLockReadGuard</a><T>>></code></h4>
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<div class='docblock'><p>Locks this rwlock with shared read access, blocking the current thread
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until it can be acquired.</p>
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<p>The calling thread will be blocked until there are no more writers which
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hold the lock. There may be other readers currently inside the lock when
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this method returns. This method does not provide any guarantees with
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respect to the ordering of whether contentious readers or writers will
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acquire the lock first.</p>
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<p>Returns an RAII guard which will release this thread's shared access
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once it is dropped.</p>
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<h1 id='errors' class='section-header'><a href='#errors'>Errors</a></h1>
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<p>This function will return an error if the RwLock is poisoned. An RwLock
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is poisoned whenever a writer panics while holding an exclusive lock.
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The failure will occur immediately after the lock has been acquired.</p>
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</div><h4 id='method.try_read' class='method'><code>fn <a href='#method.try_read' class='fnname'>try_read</a>(&self) -> <a class='enum' href='../../../bitflags/__core/result/enum.Result.html' title='bitflags::__core::result::Result'>Result</a><<a class='struct' href='../../../bitflags/__core/sync/struct.RwLockReadGuard.html' title='bitflags::__core::sync::RwLockReadGuard'>RwLockReadGuard</a><T>, <a class='enum' href='../../../bitflags/__core/sync/enum.TryLockError.html' title='bitflags::__core::sync::TryLockError'>TryLockError</a><<a class='struct' href='../../../bitflags/__core/sync/struct.RwLockReadGuard.html' title='bitflags::__core::sync::RwLockReadGuard'>RwLockReadGuard</a><T>>></code></h4>
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<div class='docblock'><p>Attempts to acquire this rwlock with shared read access.</p>
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<p>If the access could not be granted at this time, then <code>Err</code> is returned.
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Otherwise, an RAII guard is returned which will release the shared access
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when it is dropped.</p>
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<p>This function does not block.</p>
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<p>This function does not provide any guarantees with respect to the ordering
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of whether contentious readers or writers will acquire the lock first.</p>
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<h1 id='errors-1' class='section-header'><a href='#errors-1'>Errors</a></h1>
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<p>This function will return an error if the RwLock is poisoned. An RwLock
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is poisoned whenever a writer panics while holding an exclusive lock. An
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error will only be returned if the lock would have otherwise been
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acquired.</p>
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</div><h4 id='method.write' class='method'><code>fn <a href='#method.write' class='fnname'>write</a>(&self) -> <a class='enum' href='../../../bitflags/__core/result/enum.Result.html' title='bitflags::__core::result::Result'>Result</a><<a class='struct' href='../../../bitflags/__core/sync/struct.RwLockWriteGuard.html' title='bitflags::__core::sync::RwLockWriteGuard'>RwLockWriteGuard</a><T>, <a class='struct' href='../../../bitflags/__core/sync/struct.PoisonError.html' title='bitflags::__core::sync::PoisonError'>PoisonError</a><<a class='struct' href='../../../bitflags/__core/sync/struct.RwLockWriteGuard.html' title='bitflags::__core::sync::RwLockWriteGuard'>RwLockWriteGuard</a><T>>></code></h4>
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<div class='docblock'><p>Locks this rwlock with exclusive write access, blocking the current
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thread until it can be acquired.</p>
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<p>This function will not return while other writers or other readers
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currently have access to the lock.</p>
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<p>Returns an RAII guard which will drop the write access of this rwlock
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when dropped.</p>
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<h1 id='errors-2' class='section-header'><a href='#errors-2'>Errors</a></h1>
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<p>This function will return an error if the RwLock is poisoned. An RwLock
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is poisoned whenever a writer panics while holding an exclusive lock.
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An error will be returned when the lock is acquired.</p>
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</div><h4 id='method.try_write' class='method'><code>fn <a href='#method.try_write' class='fnname'>try_write</a>(&self) -> <a class='enum' href='../../../bitflags/__core/result/enum.Result.html' title='bitflags::__core::result::Result'>Result</a><<a class='struct' href='../../../bitflags/__core/sync/struct.RwLockWriteGuard.html' title='bitflags::__core::sync::RwLockWriteGuard'>RwLockWriteGuard</a><T>, <a class='enum' href='../../../bitflags/__core/sync/enum.TryLockError.html' title='bitflags::__core::sync::TryLockError'>TryLockError</a><<a class='struct' href='../../../bitflags/__core/sync/struct.RwLockWriteGuard.html' title='bitflags::__core::sync::RwLockWriteGuard'>RwLockWriteGuard</a><T>>></code></h4>
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||
<div class='docblock'><p>Attempts to lock this rwlock with exclusive write access.</p>
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||
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<p>If the lock could not be acquired at this time, then <code>Err</code> is returned.
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||
Otherwise, an RAII guard is returned which will release the lock when
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||
it is dropped.</p>
|
||
|
||
<p>This function does not block.</p>
|
||
|
||
<p>This function does not provide any guarantees with respect to the ordering
|
||
of whether contentious readers or writers will acquire the lock first.</p>
|
||
|
||
<h1 id='errors-3' class='section-header'><a href='#errors-3'>Errors</a></h1>
|
||
<p>This function will return an error if the RwLock is poisoned. An RwLock
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||
is poisoned whenever a writer panics while holding an exclusive lock. An
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||
error will only be returned if the lock would have otherwise been
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||
acquired.</p>
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||
</div><h4 id='method.is_poisoned' class='method'><code>fn <a href='#method.is_poisoned' class='fnname'>is_poisoned</a>(&self) -> <a class='primitive' href='https://doc.rust-lang.org/nightly/bitflags/primitive.bool.html'>bool</a></code><span class="since">1.2.0</span></h4>
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<div class='docblock'><p>Determines whether the lock is poisoned.</p>
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<p>If another thread is active, the lock can still become poisoned at any
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||
time. You should not trust a <code>false</code> value for program correctness
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||
without additional synchronization.</p>
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</div><h4 id='method.into_inner' class='method'><code>fn <a href='#method.into_inner' class='fnname'>into_inner</a>(self) -> <a class='enum' href='../../../bitflags/__core/result/enum.Result.html' title='bitflags::__core::result::Result'>Result</a><T, <a class='struct' href='../../../bitflags/__core/sync/struct.PoisonError.html' title='bitflags::__core::sync::PoisonError'>PoisonError</a><T>></code><span class="since">1.6.0</span></h4>
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<div class='docblock'><p>Consumes this <code>RwLock</code>, returning the underlying data.</p>
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<h1 id='errors-4' class='section-header'><a href='#errors-4'>Errors</a></h1>
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<p>This function will return an error if the RwLock is poisoned. An RwLock
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is poisoned whenever a writer panics while holding an exclusive lock. An
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error will only be returned if the lock would have otherwise been
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acquired.</p>
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</div><h4 id='method.get_mut' class='method'><code>fn <a href='#method.get_mut' class='fnname'>get_mut</a>(&mut self) -> <a class='enum' href='../../../bitflags/__core/result/enum.Result.html' title='bitflags::__core::result::Result'>Result</a><&mut T, <a class='struct' href='../../../bitflags/__core/sync/struct.PoisonError.html' title='bitflags::__core::sync::PoisonError'>PoisonError</a><&mut T>></code><span class="since">1.6.0</span></h4>
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<div class='docblock'><p>Returns a mutable reference to the underlying data.</p>
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<p>Since this call borrows the <code>RwLock</code> mutably, no actual locking needs to
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take place---the mutable borrow statically guarantees no locks exist.</p>
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<h1 id='errors-5' class='section-header'><a href='#errors-5'>Errors</a></h1>
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<p>This function will return an error if the RwLock is poisoned. An RwLock
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is poisoned whenever a writer panics while holding an exclusive lock. An
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error will only be returned if the lock would have otherwise been
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acquired.</p>
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</div></div><h2 id='implementations'>Trait Implementations</h2><h3 class='impl'><code>impl<T> <a class='trait' href='../../../bitflags/__core/panic/trait.UnwindSafe.html' title='bitflags::__core::panic::UnwindSafe'>UnwindSafe</a> for <a class='struct' href='../../../bitflags/__core/sync/struct.RwLock.html' title='bitflags::__core::sync::RwLock'>RwLock</a><T> <span class='where'>where T: ?<a class='trait' href='../../../bitflags/__core/marker/trait.Sized.html' title='bitflags::__core::marker::Sized'>Sized</a></span></code><span class="since">1.9.0</span></h3><div class='impl-items'></div><h3 class='impl'><code>impl<T> <a class='trait' href='../../../bitflags/__core/marker/trait.Send.html' title='bitflags::__core::marker::Send'>Send</a> for <a class='struct' href='../../../bitflags/__core/sync/struct.RwLock.html' title='bitflags::__core::sync::RwLock'>RwLock</a><T> <span class='where'>where T: <a class='trait' href='../../../bitflags/__core/marker/trait.Send.html' title='bitflags::__core::marker::Send'>Send</a> + <a class='trait' href='../../../bitflags/__core/marker/trait.Sync.html' title='bitflags::__core::marker::Sync'>Sync</a> + ?<a class='trait' href='../../../bitflags/__core/marker/trait.Sized.html' title='bitflags::__core::marker::Sized'>Sized</a></span></code></h3><div class='impl-items'></div><h3 class='impl'><code>impl<T> <a class='trait' href='../../../bitflags/__core/marker/trait.Sync.html' title='bitflags::__core::marker::Sync'>Sync</a> for <a class='struct' href='../../../bitflags/__core/sync/struct.RwLock.html' title='bitflags::__core::sync::RwLock'>RwLock</a><T> <span class='where'>where T: <a class='trait' href='../../../bitflags/__core/marker/trait.Send.html' title='bitflags::__core::marker::Send'>Send</a> + <a class='trait' href='../../../bitflags/__core/marker/trait.Sync.html' title='bitflags::__core::marker::Sync'>Sync</a> + ?<a class='trait' href='../../../bitflags/__core/marker/trait.Sized.html' title='bitflags::__core::marker::Sized'>Sized</a></span></code></h3><div class='impl-items'></div><h3 class='impl'><code>impl<T> <a class='trait' href='../../../bitflags/__core/ops/trait.Drop.html' title='bitflags::__core::ops::Drop'>Drop</a> for <a class='struct' href='../../../bitflags/__core/sync/struct.RwLock.html' title='bitflags::__core::sync::RwLock'>RwLock</a><T> <span class='where'>where T: ?<a class='trait' href='../../../bitflags/__core/marker/trait.Sized.html' title='bitflags::__core::marker::Sized'>Sized</a></span></code></h3><div class='impl-items'><h4 id='method.drop' class='method'><code>fn <a href='../../../bitflags/__core/ops/trait.Drop.html#tymethod.drop' class='fnname'>drop</a>(&mut self)</code></h4>
|
||
</div><h3 class='impl'><code>impl<T> <a class='trait' href='../../../bitflags/__core/fmt/trait.Debug.html' title='bitflags::__core::fmt::Debug'>Debug</a> for <a class='struct' href='../../../bitflags/__core/sync/struct.RwLock.html' title='bitflags::__core::sync::RwLock'>RwLock</a><T> <span class='where'>where T: <a class='trait' href='../../../bitflags/__core/fmt/trait.Debug.html' title='bitflags::__core::fmt::Debug'>Debug</a> + ?<a class='trait' href='../../../bitflags/__core/marker/trait.Sized.html' title='bitflags::__core::marker::Sized'>Sized</a></span></code></h3><div class='impl-items'><h4 id='method.fmt' class='method'><code>fn <a href='../../../bitflags/__core/fmt/trait.Debug.html#tymethod.fmt' class='fnname'>fmt</a>(&self, f: &mut <a class='struct' href='../../../bitflags/__core/fmt/struct.Formatter.html' title='bitflags::__core::fmt::Formatter'>Formatter</a>) -> <a class='enum' href='../../../bitflags/__core/result/enum.Result.html' title='bitflags::__core::result::Result'>Result</a><<a class='primitive' href='https://doc.rust-lang.org/nightly/bitflags/primitive.tuple.html'>()</a>, <a class='struct' href='../../../bitflags/__core/fmt/struct.Error.html' title='bitflags::__core::fmt::Error'>Error</a>></code></h4>
|
||
</div><h3 class='impl'><code>impl<T> <a class='trait' href='../../../bitflags/__core/default/trait.Default.html' title='bitflags::__core::default::Default'>Default</a> for <a class='struct' href='../../../bitflags/__core/sync/struct.RwLock.html' title='bitflags::__core::sync::RwLock'>RwLock</a><T> <span class='where'>where T: <a class='trait' href='../../../bitflags/__core/default/trait.Default.html' title='bitflags::__core::default::Default'>Default</a></span></code><span class="since">1.9.0</span></h3><div class='impl-items'><h4 id='method.default' class='method'><code>fn <a href='../../../bitflags/__core/default/trait.Default.html#tymethod.default' class='fnname'>default</a>() -> <a class='struct' href='../../../bitflags/__core/sync/struct.RwLock.html' title='bitflags::__core::sync::RwLock'>RwLock</a><T></code></h4>
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<div class="infos">
|
||
<h2>Search Tricks</h2>
|
||
|
||
<p>
|
||
Prefix searches with a type followed by a colon (e.g.
|
||
<code>fn:</code>) to restrict the search to a given type.
|
||
</p>
|
||
|
||
<p>
|
||
Accepted types are: <code>fn</code>, <code>mod</code>,
|
||
<code>struct</code>, <code>enum</code>,
|
||
<code>trait</code>, <code>type</code>, <code>macro</code>,
|
||
and <code>const</code>.
|
||
</p>
|
||
|
||
<p>
|
||
Search functions by type signature (e.g.
|
||
<code>vec -> usize</code> or <code>* -> vec</code>)
|
||
</p>
|
||
</div>
|
||
</div>
|
||
</aside>
|
||
|
||
|
||
|
||
<script>
|
||
window.rootPath = "../../../";
|
||
window.currentCrate = "bitflags";
|
||
window.playgroundUrl = "";
|
||
</script>
|
||
<script src="../../../jquery.js"></script>
|
||
<script src="../../../main.js"></script>
|
||
|
||
<script defer src="../../../search-index.js"></script>
|
||
</body>
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</html> |