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        <p class='location'>Struct BufferMapCmd</p><div class="sidebar-elems"><div class="block items"><a class="sidebar-title" href="#methods">Methods</a><div class="sidebar-links"><a href="#method.flags">flags</a><a href="#method.read">read</a><a href="#method.write">write</a><a href="#method.write_invalidate">write_invalidate</a><a href="#method.len">len</a><a href="#method.queue">queue</a><a href="#method.offset">offset</a><a href="#method.ewait">ewait</a><a href="#method.enew">enew</a><a href="#method.enq">enq</a><a href="#method.enq_async">enq_async</a></div></div><p class='location'><a href='../index.html'>ocl</a>::<wbr><a href='index.html'>builders</a></p><script>window.sidebarCurrent = {name: 'BufferMapCmd', ty: 'struct', relpath: ''};</script><script defer src="sidebar-items.js"></script></div>
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<h1 class='fqn'><span class='in-band'>Struct <a href='../index.html'>ocl</a>::<wbr><a href='index.html'>builders</a>::<wbr><a class="struct" href=''>BufferMapCmd</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>]
                   </a>
               </span><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1393-1397' title='goto source code'>[src]</a></span></h1>
<pre class='rust struct'><div class="docblock attributes">#[must_use = "commands do nothing unless enqueued"]
</div>pub struct BufferMapCmd&lt;'c, T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: 'c + <a class="trait" href="../../ocl/traits/trait.OclPrm.html" title="trait ocl::traits::OclPrm">OclPrm</a>,&nbsp;</span> { /* fields omitted */ }</pre><div class='docblock'><p>A command builder used to enqueue a map command.</p>
<p>Enqueuing a map command will map a region of a buffer into the host
address space and return a <a href="struct.MemMap.html"><code>MemMap</code></a> or <a href="async/struct.FutureMemMap.html"><code>FutureMemMap</code></a>, allowing access
to this mapped region. Accessing memory via a <a href="struct.MemMap.html"><code>MemMap</code></a> is exactly like
using a <a href="https://doc.rust-lang.org/std/primitive.slice.html">slice</a>.</p>
<p>See <a href="https://www.khronos.org/registry/OpenCL/sdk/1.2/docs/man/xhtml/clEnqueueMapBuffer.html">SDK</a> docs for more details.</p>
</div>
                    <h2 id='methods' class='small-section-header'>
                      Methods<a href='#methods' class='anchor'></a>
                    </h2>
                <h3 id='impl' class='impl'><span class='in-band'><code>impl&lt;'c, T&gt; <a class="struct" href="../../ocl/builders/struct.BufferMapCmd.html" title="struct ocl::builders::BufferMapCmd">BufferMapCmd</a>&lt;'c, T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="../../ocl/traits/trait.OclPrm.html" title="trait ocl::traits::OclPrm">OclPrm</a>,&nbsp;</span></code><a href='#impl' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1399-1649' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.flags' class="method"><span id='flags.v' class='invisible'><code>pub fn <a href='#method.flags' class='fnname'>flags</a>(self, flags: <a class="struct" href="../../ocl/flags/struct.MapFlags.html" title="struct ocl::flags::MapFlags">MapFlags</a>) -&gt; <a class="struct" href="../../ocl/builders/struct.BufferMapCmd.html" title="struct ocl::builders::BufferMapCmd">BufferMapCmd</a>&lt;'c, T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1413-1416' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Specifies the flags to be used for this map command.</p>
<p>Flags can also be specified using the <code>::read</code>, <code>::write</code>, and
<code>::write_invalidate</code> methods instead.</p>
<p>See <a href="https://www.khronos.org/registry/OpenCL/sdk/1.2/docs/man/xhtml/clEnqueueMapBuffer.html">SDK</a> docs for more details.</p>
</div><h4 id='method.read' class="method"><span id='read.v' class='invisible'><code>pub fn <a href='#method.read' class='fnname'>read</a>(self) -&gt; <a class="struct" href="../../ocl/builders/struct.BufferMapCmd.html" title="struct ocl::builders::BufferMapCmd">BufferMapCmd</a>&lt;'c, T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1425-1428' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Specifies that the memory object is being mapped for reading.</p>
<p>Sets the flag to be used for this map command to <code>[CL_]MAP_READ</code>.</p>
<p>This is the fastest way to move data from device to host for many use
cases when used with buffers created with the <code>MEM_ALLOC_HOST_PTR</code> or
<code>MEM_USE_HOST_PTR</code> flags.</p>
</div><h4 id='method.write' class="method"><span id='write.v' class='invisible'><code>pub fn <a href='#method.write' class='fnname'>write</a>(self) -&gt; <a class="struct" href="../../ocl/builders/struct.BufferMapCmd.html" title="struct ocl::builders::BufferMapCmd">BufferMapCmd</a>&lt;'c, T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1441-1444' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Specifies that the memory object is being mapped for writing.</p>
<p>Sets the flag to be used for this map command to <code>[CL_]MAP_WRITE</code>.</p>
<p>This is not the most efficient method of transferring data from host
to device due to the memory being synchronized beforehand. Prefer
<code>::write_invalidate</code> unless you need the memory region to be updated
(e.g. if you are only writing to particular portions of the data, and
will not be overwriting the entire contents, etc.). Use this with
buffers created with the <code>MEM_ALLOC_HOST_PTR</code> or <code>MEM_USE_HOST_PTR</code>
flags for best performance.</p>
</div><h4 id='method.write_invalidate' class="method"><span id='write_invalidate.v' class='invisible'><code>pub fn <a href='#method.write_invalidate' class='fnname'>write_invalidate</a>(self) -&gt; <a class="struct" href="../../ocl/builders/struct.BufferMapCmd.html" title="struct ocl::builders::BufferMapCmd">BufferMapCmd</a>&lt;'c, T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1459-1462' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Specifies that the memory object is being mapped for writing and that
the local (host) memory region may contain stale data that must be
completely overwritten before unmapping.</p>
<p>Sets the flag to be used for this map command to
<code>[CL_]MAP_WRITE_INVALIDATE_REGION</code>.</p>
<p>This option may provide a substantial performance improvement when
writing and is the fastest method for moving data in bulk from host to
device memory when used with buffers created with the
<code>MEM_ALLOC_HOST_PTR</code> or <code>MEM_USE_HOST_PTR</code> flags. Only use this when
you will be overwriting the entire contents of the mapped region
otherwise you will send stale or junk data to the device.</p>
</div><h4 id='method.len' class="method"><span id='len.v' class='invisible'><code>pub fn <a href='#method.len' class='fnname'>len</a>(self, len: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>) -&gt; <a class="struct" href="../../ocl/builders/struct.BufferMapCmd.html" title="struct ocl::builders::BufferMapCmd">BufferMapCmd</a>&lt;'c, T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1470-1473' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Specifies the length of the region to map.</p>
<p>If unspecified the entire buffer will be mapped.</p>
</div><h4 id='method.queue' class="method"><span id='queue.v' class='invisible'><code>pub fn <a href='#method.queue' class='fnname'>queue</a>(self, queue: &amp;'c <a class="struct" href="../../ocl/struct.Queue.html" title="struct ocl::Queue">Queue</a>) -&gt; <a class="struct" href="../../ocl/builders/struct.BufferMapCmd.html" title="struct ocl::builders::BufferMapCmd">BufferMapCmd</a>&lt;'c, T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1480-1483' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Specifies a queue to use for this call only.</p>
<p>Overrides the buffer's default queue if one is set. If no default
queue is set, this method <strong>must</strong> be called before enqueuing the
command.</p>
</div><h4 id='method.offset' class="method"><span id='offset.v' class='invisible'><code>pub fn <a href='#method.offset' class='fnname'>offset</a>(self, offset: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>) -&gt; <a class="struct" href="../../ocl/builders/struct.BufferMapCmd.html" title="struct ocl::builders::BufferMapCmd">BufferMapCmd</a>&lt;'c, T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1491-1493' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Sets the linear offset for an operation.</p>
<h2 id="panics" class="section-header"><a href="#panics">Panics</a></h2>
<p>The 'shape' may not have already been set to rectangular by the
<code>::rect</code> function.</p>
</div><h4 id='method.ewait' class="method"><span id='ewait.v' class='invisible'><code>pub fn <a href='#method.ewait' class='fnname'>ewait</a>&lt;'e, Ewl&gt;(self, ewait: Ewl) -&gt; <a class="struct" href="../../ocl/builders/struct.BufferMapCmd.html" title="struct ocl::builders::BufferMapCmd">BufferMapCmd</a>&lt;'c, T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;'e: 'c,<br>&nbsp;&nbsp;&nbsp;&nbsp;Ewl: <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a>&lt;<a class="enum" href="../../ocl/builders/enum.ClWaitListPtrEnum.html" title="enum ocl::builders::ClWaitListPtrEnum">ClWaitListPtrEnum</a>&lt;'e&gt;&gt;,&nbsp;</span></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1523-1527' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Specifies an event or list of events to wait on before the command
will run.</p>
<p>When events generated using the <code>::enew</code> method of <strong>other</strong>,
previously enqueued commands are passed here (either individually or
as part of an <a href="struct.EventList.html"><code>EventList</code></a>), this command will not execute until
those commands have completed.</p>
<p>Using events can compliment the use of queues to order commands by
creating temporal dependencies between them (where commands in one
queue must wait for the completion of commands in another). Events can
also supplant queues altogether when, for example, using out-of-order
queues.</p>
<h1 id="example" class="section-header"><a href="#example">Example</a></h1>
<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">
<span class="comment">// Create an event list:</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">event_list</span> <span class="op">=</span> <span class="ident">EventList</span>::<span class="ident">new</span>();
<span class="comment">// Enqueue a kernel on `queue_1`, creating an event representing the kernel</span>
<span class="comment">// command in our list:</span>
<span class="ident">kernel</span>.<span class="ident">cmd</span>().<span class="ident">queue</span>(<span class="kw-2">&amp;</span><span class="ident">queue_1</span>).<span class="ident">enew</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">event_list</span>).<span class="ident">enq</span>()<span class="question-mark">?</span>;
<span class="comment">// Map a buffer using `queue_2`, ensuring the map does not begin until</span>
<span class="comment">// after the kernel command has completed:</span>
<span class="ident">buffer</span>.<span class="ident">map</span>().<span class="ident">queue</span>(<span class="kw-2">&amp;</span><span class="ident">queue_2</span>).<span class="ident">ewait</span>(<span class="kw-2">&amp;</span><span class="ident">event_list</span>).<span class="ident">enq_async</span>()<span class="question-mark">?</span>;</pre>
</div><h4 id='method.enew' class="method"><span id='enew.v' class='invisible'><code>pub fn <a href='#method.enew' class='fnname'>enew</a>&lt;'e, En&gt;(self, enew: En) -&gt; <a class="struct" href="../../ocl/builders/struct.BufferMapCmd.html" title="struct ocl::builders::BufferMapCmd">BufferMapCmd</a>&lt;'c, T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;'e: 'c,<br>&nbsp;&nbsp;&nbsp;&nbsp;En: <a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a>&lt;<a class="enum" href="../../ocl/builders/enum.ClNullEventPtrEnum.html" title="enum ocl::builders::ClNullEventPtrEnum">ClNullEventPtrEnum</a>&lt;'e&gt;&gt;,&nbsp;</span></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1560-1564' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Specifies the destination to store a new, optionally created event
associated with this command.</p>
<p>The destination can be a mutable reference to an empty event (created
using <a href="struct.Event.html#method.empty"><code>Event::empty</code></a>) or a mutable reference to an event list.</p>
<p>After this command is enqueued, the event in the destination can be
passed to the <code>::ewait</code> method of another command. Doing so will cause
the other command to wait until this command has completed before
executing.</p>
<p>Using events can compliment the use of queues to order commands by
creating temporal dependencies between them (where commands in one
queue must wait for the completion of commands in another). Events can
also supplant queues altogether when, for example, using out-of-order
queues.</p>
<h1 id="example-1" class="section-header"><a href="#example-1">Example</a></h1>
<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">
<span class="comment">// Create an event list:</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">event</span> <span class="op">=</span> <span class="ident">Event</span>::<span class="ident">empty</span>();
<span class="comment">// Enqueue a kernel on `queue_1`, creating an event representing the kernel</span>
<span class="comment">// command in our list:</span>
<span class="ident">kernel</span>.<span class="ident">cmd</span>().<span class="ident">queue</span>(<span class="kw-2">&amp;</span><span class="ident">queue_1</span>).<span class="ident">enew</span>(<span class="kw-2">&amp;</span><span class="kw-2">mut</span> <span class="ident">event</span>).<span class="ident">enq</span>()<span class="question-mark">?</span>;
<span class="comment">// Map a buffer using `queue_2`, ensuring the map does not begin until</span>
<span class="comment">// after the kernel command has completed:</span>
<span class="ident">buffer</span>.<span class="ident">map</span>().<span class="ident">queue</span>(<span class="kw-2">&amp;</span><span class="ident">queue_2</span>).<span class="ident">ewait</span>(<span class="kw-2">&amp;</span><span class="ident">event</span>).<span class="ident">enq_async</span>()<span class="question-mark">?</span>;</pre>
</div><h4 id='method.enq' class="method"><span id='enq.v' class='invisible'><code>pub unsafe fn <a href='#method.enq' class='fnname'>enq</a>(self) -&gt; <a class="type" href="../../ocl/error/type.Result.html" title="type ocl::error::Result">OclResult</a>&lt;<a class="struct" href="../../ocl/struct.MemMap.html" title="struct ocl::MemMap">MemMap</a>&lt;T&gt;&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1605-1615' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Enqueues a map command, blocking the current thread until it
completes and returns a reference to the mapped memory.</p>
<h2 id="safety" class="section-header"><a href="#safety">Safety</a></h2>
<p>The caller must ensure that either only one mapping of a buffer exists
at a time or that, if simultaneously mapping for the purposes of
sub-region access or whole-buffer aliasing, no two mappings will allow
writes to the same memory region at the same time. Use atomics or some
other synchronization mechanism to ensure this.</p>
</div><h4 id='method.enq_async' class="method"><span id='enq_async.v' class='invisible'><code>pub unsafe fn <a href='#method.enq_async' class='fnname'>enq_async</a>(self) -&gt; <a class="type" href="../../ocl/error/type.Result.html" title="type ocl::error::Result">OclResult</a>&lt;<a class="struct" href="../../ocl/struct.FutureMemMap.html" title="struct ocl::FutureMemMap">FutureMemMap</a>&lt;T&gt;&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/ocl/standard/buffer.rs.html#1629-1648' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Enqueues a map command and returns a future representing the
completion of that map command.</p>
<p>The returned future will resolve to a reference to the mapped memory.</p>
<h2 id="safety-1" class="section-header"><a href="#safety-1">Safety</a></h2>
<p>The caller must ensure that either only one mapping of a buffer exists
at a time or that, if simultaneously mapping for the purposes of
sub-region access or whole-buffer aliasing, no two mappings will allow
writes to the same memory region at the same time. Use atomics or some
other synchronization mechanism to ensure this.</p>
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