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<div class="refentry">
<a name="boost.lockfree.queue"></a><div class="titlepage"></div>
<div class="refnamediv">
<h2><span class="refentrytitle">Class template queue</span></h2>
<p>boost::lockfree::queue</p>
</div>
<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../../lockfree/reference.html#header.boost.lockfree.queue_hpp" title="Header <boost/lockfree/queue.hpp>">boost/lockfree/queue.hpp</a>>
</span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">,</span> <span class="keyword">typename</span><span class="special">...</span> Options<span class="special">></span>
<span class="keyword">class</span> <a class="link" href="queue.html" title="Class template queue">queue</a> <span class="special">{</span>
<span class="keyword">public</span><span class="special">:</span>
<span class="comment">// types</span>
<span class="keyword">typedef</span> <span class="identifier">T</span> <a name="boost.lockfree.queue.value_type"></a><span class="identifier">value_type</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">implementation_defined</span><span class="special">::</span><span class="identifier">allocator</span> <a name="boost.lockfree.queue.allocator"></a><span class="identifier">allocator</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">implementation_defined</span><span class="special">::</span><span class="identifier">size_type</span> <a name="boost.lockfree.queue.size_type"></a><span class="identifier">size_type</span><span class="special">;</span>
<span class="comment">// <a class="link" href="queue.html#boost.lockfree.queueconstruct-copy-destruct">construct/copy/destruct</a></span>
<a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_3-bb"><span class="identifier">queue</span></a><span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> U<span class="special">></span> <span class="keyword">explicit</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_4-bb"><span class="identifier">queue</span></a><span class="special">(</span><span class="emphasis"><em><span class="identifier">unspecified</span></em></span><span class="special">)</span><span class="special">;</span>
<span class="keyword">explicit</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_5-bb"><span class="identifier">queue</span></a><span class="special">(</span><span class="identifier">allocator</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">explicit</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_6-bb"><span class="identifier">queue</span></a><span class="special">(</span><span class="identifier">size_type</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> U<span class="special">></span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_7-bb"><span class="identifier">queue</span></a><span class="special">(</span><span class="identifier">size_type</span><span class="special">,</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span><span class="special">)</span><span class="special">;</span>
<a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_12-bb"><span class="special">~</span><span class="identifier">queue</span></a><span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="special">;</span>
<span class="comment">// <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11-bb">public member functions</a></span>
<span class="keyword">bool</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_1-bb"><span class="identifier">is_lock_free</span></a><span class="special">(</span><span class="keyword">void</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">void</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_2-bb"><span class="identifier">reserve</span></a><span class="special">(</span><span class="identifier">size_type</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">void</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_3-bb"><span class="identifier">reserve_unsafe</span></a><span class="special">(</span><span class="identifier">size_type</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">bool</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_4-bb"><span class="identifier">empty</span></a><span class="special">(</span><span class="keyword">void</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="keyword">bool</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_5-bb"><span class="identifier">push</span></a><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">bool</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_6-bb"><span class="identifier">bounded_push</span></a><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">bool</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_7-bb"><span class="identifier">unsynchronized_push</span></a><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">bool</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_8-bb"><span class="identifier">pop</span></a><span class="special">(</span><span class="identifier">T</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> U<span class="special">></span> <span class="keyword">bool</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_9-bb"><span class="identifier">pop</span></a><span class="special">(</span><span class="identifier">U</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">bool</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_10-bb"><span class="identifier">unsynchronized_pop</span></a><span class="special">(</span><span class="identifier">T</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> U<span class="special">></span> <span class="keyword">bool</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_11-bb"><span class="identifier">unsynchronized_pop</span></a><span class="special">(</span><span class="identifier">U</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Functor<span class="special">></span> <span class="keyword">bool</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_12-bb"><span class="identifier">consume_one</span></a><span class="special">(</span><span class="identifier">Functor</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Functor<span class="special">></span> <span class="keyword">bool</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_13-bb"><span class="identifier">consume_one</span></a><span class="special">(</span><span class="identifier">Functor</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Functor<span class="special">></span> <span class="identifier">size_t</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_14-bb"><span class="identifier">consume_all</span></a><span class="special">(</span><span class="identifier">Functor</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Functor<span class="special">></span> <span class="identifier">size_t</span> <a class="link" href="queue.html#id-1_3_23_6_3_1_1_1_11_15-bb"><span class="identifier">consume_all</span></a><span class="special">(</span><span class="identifier">Functor</span> <span class="keyword">const</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="special">}</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id-1.3.23.6.3.3.4"></a><h2>Description</h2>
<p>The queue class provides a multi-writer/multi-reader queue, pushing and popping is lock-free, construction/destruction has to be synchronized. It uses a freelist for memory management, freed nodes are pushed to the freelist and not returned to the OS before the queue is destroyed.</p>
<p><span class="bold"><strong>Policies:</strong></span> </p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p><a class="link" href="fixed_sized.html" title="Struct template fixed_sized">boost::lockfree::fixed_sized</a>, defaults to <code class="computeroutput">boost::lockfree::fixed_sized<false></code> <br>
Can be used to completely disable dynamic memory allocations during push in order to ensure lockfree behavior. <br>
If the data structure is configured as fixed-sized, the internal nodes are stored inside an array and they are addressed by array indexing. This limits the possible size of the queue to the number of elements that can be addressed by the index type (usually 2**16-2), but on platforms that lack double-width compare-and-exchange instructions, this is the best way to achieve lock-freedom.</p></li>
<li class="listitem"><p><a class="link" href="capacity.html" title="Struct template capacity">boost::lockfree::capacity</a>, optional <br>
If this template argument is passed to the options, the size of the queue is set at compile-time.<br>
This option implies <code class="computeroutput">fixed_sized<true></code> </p></li>
<li class="listitem"><p><a class="link" href="allocator.html" title="Struct template allocator">boost::lockfree::allocator</a>, defaults to <code class="computeroutput"><a class="link" href="allocator.html" title="Struct template allocator">boost::lockfree::allocator</a><std::allocator<void>></code> <br>
Specifies the allocator that is used for the internal freelist</p></li>
</ul></div>
<p>
</p>
<p><span class="bold"><strong>Requirements:</strong></span> </p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p>T must have a copy constructor</p></li>
<li class="listitem"><p>T must have a trivial assignment operator</p></li>
<li class="listitem"><p>T must have a trivial destructor </p></li>
</ul></div>
<p>
</p>
<div class="refsect2">
<a name="id-1.3.23.6.3.3.4.5"></a><h3>
<a name="boost.lockfree.queueconstruct-copy-destruct"></a><code class="computeroutput">queue</code>
public
construct/copy/destruct</h3>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
<pre class="literallayout"><a name="id-1_3_23_6_3_1_1_1_3-bb"></a><span class="identifier">queue</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="special">;</span></pre>Construct queue. </li>
<li class="listitem"><pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> U<span class="special">></span> <span class="keyword">explicit</span> <a name="id-1_3_23_6_3_1_1_1_4-bb"></a><span class="identifier">queue</span><span class="special">(</span><span class="emphasis"><em><span class="identifier">unspecified</span></em></span> alloc<span class="special">)</span><span class="special">;</span></pre></li>
<li class="listitem"><pre class="literallayout"><span class="keyword">explicit</span> <a name="id-1_3_23_6_3_1_1_1_5-bb"></a><span class="identifier">queue</span><span class="special">(</span><span class="identifier">allocator</span> <span class="keyword">const</span> <span class="special">&</span> alloc<span class="special">)</span><span class="special">;</span></pre></li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">explicit</span> <a name="id-1_3_23_6_3_1_1_1_6-bb"></a><span class="identifier">queue</span><span class="special">(</span><span class="identifier">size_type</span> n<span class="special">)</span><span class="special">;</span></pre>Construct queue, allocate n nodes for the freelist. </li>
<li class="listitem"><pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> U<span class="special">></span> <a name="id-1_3_23_6_3_1_1_1_7-bb"></a><span class="identifier">queue</span><span class="special">(</span><span class="identifier">size_type</span> n<span class="special">,</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> alloc<span class="special">)</span><span class="special">;</span></pre></li>
<li class="listitem">
<pre class="literallayout"><a name="id-1_3_23_6_3_1_1_1_12-bb"></a><span class="special">~</span><span class="identifier">queue</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="special">;</span></pre>
<p>Destroys queue, free all nodes from freelist. </p>
</li>
</ol></div>
</div>
<div class="refsect2">
<a name="id-1.3.23.6.3.3.4.6"></a><h3>
<a name="id-1_3_23_6_3_1_1_1_11-bb"></a><code class="computeroutput">queue</code> public member functions</h3>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
<pre class="literallayout"><span class="keyword">bool</span> <a name="id-1_3_23_6_3_1_1_1_11_1-bb"></a><span class="identifier">is_lock_free</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
<p>
</p>
<div class="warning"><table border="0" summary="Warning">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="../../../../doc/src/images/warning.png"></td>
<th align="left">Warning</th>
</tr>
<tr><td align="left" valign="top"><p>It only checks, if the queue head and tail nodes and the freelist can be modified in a lock-free manner. On most platforms, the whole implementation is lock-free, if this is true. Using c++0x-style atomics, there is no possibility to provide a completely accurate implementation, because one would need to test every internal node, which is impossible if further nodes will be allocated from the operating system. </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>true, if implementation is lock-free.</p></td>
</tr></tbody>
</table></div>
</li>
<li class="listitem"><pre class="literallayout"><span class="keyword">void</span> <a name="id-1_3_23_6_3_1_1_1_11_2-bb"></a><span class="identifier">reserve</span><span class="special">(</span><span class="identifier">size_type</span> n<span class="special">)</span><span class="special">;</span></pre></li>
<li class="listitem"><pre class="literallayout"><span class="keyword">void</span> <a name="id-1_3_23_6_3_1_1_1_11_3-bb"></a><span class="identifier">reserve_unsafe</span><span class="special">(</span><span class="identifier">size_type</span> n<span class="special">)</span><span class="special">;</span></pre></li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">bool</span> <a name="id-1_3_23_6_3_1_1_1_11_4-bb"></a><span class="identifier">empty</span><span class="special">(</span><span class="keyword">void</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
<p>Check if the queue is empty</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>The result is only accurate, if no other thread modifies the queue. Therefore it is rarely practical to use this value in program logic. </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>true, if the queue is empty, false otherwise </p></td>
</tr></tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">bool</span> <a name="id-1_3_23_6_3_1_1_1_11_5-bb"></a><span class="identifier">push</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&</span> t<span class="special">)</span><span class="special">;</span></pre>
<p>Pushes object t to the queue.</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>Thread-safe. If internal memory pool is exhausted and the memory pool is not fixed-sized, a new node will be allocated from the OS. This may not be lock-free. </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">Postconditions:</span></p></td>
<td><p>object will be pushed to the queue, if internal node can be allocated </p></td>
</tr>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>true, if the push operation is successful.</p></td>
</tr>
</tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">bool</span> <a name="id-1_3_23_6_3_1_1_1_11_6-bb"></a><span class="identifier">bounded_push</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&</span> t<span class="special">)</span><span class="special">;</span></pre>
<p>Pushes object t to the queue.</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>Thread-safe and non-blocking. If internal memory pool is exhausted, operation will fail </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">Postconditions:</span></p></td>
<td><p>object will be pushed to the queue, if internal node can be allocated </p></td>
</tr>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>true, if the push operation is successful.</p></td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>if memory allocator throws </td>
</tr>
</tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">bool</span> <a name="id-1_3_23_6_3_1_1_1_11_7-bb"></a><span class="identifier">unsynchronized_push</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span> <span class="special">&</span> t<span class="special">)</span><span class="special">;</span></pre>
<p>Pushes object t to the queue.</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>Not Thread-safe. If internal memory pool is exhausted and the memory pool is not fixed-sized, a new node will be allocated from the OS. This may not be lock-free. </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">Postconditions:</span></p></td>
<td><p>object will be pushed to the queue, if internal node can be allocated </p></td>
</tr>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>true, if the push operation is successful.</p></td>
</tr>
<tr>
<td><p><span class="term">Throws:</span></p></td>
<td>if memory allocator throws </td>
</tr>
</tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">bool</span> <a name="id-1_3_23_6_3_1_1_1_11_8-bb"></a><span class="identifier">pop</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&</span> ret<span class="special">)</span><span class="special">;</span></pre>
<p>Pops object from queue.</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>Thread-safe and non-blocking </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">Postconditions:</span></p></td>
<td><p>if pop operation is successful, object will be copied to ret. </p></td>
</tr>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>true, if the pop operation is successful, false if queue was empty.</p></td>
</tr>
</tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> U<span class="special">></span> <span class="keyword">bool</span> <a name="id-1_3_23_6_3_1_1_1_11_9-bb"></a><span class="identifier">pop</span><span class="special">(</span><span class="identifier">U</span> <span class="special">&</span> ret<span class="special">)</span><span class="special">;</span></pre>
<p>Pops object from queue.</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>Thread-safe and non-blocking </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">Requires:</span></p></td>
<td><p>type U must be constructible by T and copyable, or T must be convertible to U </p></td>
</tr>
<tr>
<td><p><span class="term">Postconditions:</span></p></td>
<td><p>if pop operation is successful, object will be copied to ret. </p></td>
</tr>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>true, if the pop operation is successful, false if queue was empty.</p></td>
</tr>
</tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">bool</span> <a name="id-1_3_23_6_3_1_1_1_11_10-bb"></a><span class="identifier">unsynchronized_pop</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&</span> ret<span class="special">)</span><span class="special">;</span></pre>
<p>Pops object from queue.</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>Not thread-safe, but non-blocking </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">Postconditions:</span></p></td>
<td><p>if pop operation is successful, object will be copied to ret. </p></td>
</tr>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>true, if the pop operation is successful, false if queue was empty.</p></td>
</tr>
</tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> U<span class="special">></span> <span class="keyword">bool</span> <a name="id-1_3_23_6_3_1_1_1_11_11-bb"></a><span class="identifier">unsynchronized_pop</span><span class="special">(</span><span class="identifier">U</span> <span class="special">&</span> ret<span class="special">)</span><span class="special">;</span></pre>
<p>Pops object from queue.</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>Not thread-safe, but non-blocking </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">Requires:</span></p></td>
<td><p>type U must be constructible by T and copyable, or T must be convertible to U </p></td>
</tr>
<tr>
<td><p><span class="term">Postconditions:</span></p></td>
<td><p>if pop operation is successful, object will be copied to ret. </p></td>
</tr>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>true, if the pop operation is successful, false if queue was empty.</p></td>
</tr>
</tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Functor<span class="special">></span> <span class="keyword">bool</span> <a name="id-1_3_23_6_3_1_1_1_11_12-bb"></a><span class="identifier">consume_one</span><span class="special">(</span><span class="identifier">Functor</span> <span class="special">&</span> f<span class="special">)</span><span class="special">;</span></pre>
<p>consumes one element via a functor</p>
<p>pops one element from the queue and applies the functor on this object</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>Thread-safe and non-blocking, if functor is thread-safe and non-blocking </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>true, if one element was consumed</p></td>
</tr></tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Functor<span class="special">></span> <span class="keyword">bool</span> <a name="id-1_3_23_6_3_1_1_1_11_13-bb"></a><span class="identifier">consume_one</span><span class="special">(</span><span class="identifier">Functor</span> <span class="keyword">const</span> <span class="special">&</span> f<span class="special">)</span><span class="special">;</span></pre>
<p>consumes one element via a functor</p>
<p>pops one element from the queue and applies the functor on this object</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>Thread-safe and non-blocking, if functor is thread-safe and non-blocking </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>true, if one element was consumed</p></td>
</tr></tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Functor<span class="special">></span> <span class="identifier">size_t</span> <a name="id-1_3_23_6_3_1_1_1_11_14-bb"></a><span class="identifier">consume_all</span><span class="special">(</span><span class="identifier">Functor</span> <span class="special">&</span> f<span class="special">)</span><span class="special">;</span></pre>
<p>consumes all elements via a functor</p>
<p>sequentially pops all elements from the queue and applies the functor on each object</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>Thread-safe and non-blocking, if functor is thread-safe and non-blocking </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>number of elements that are consumed</p></td>
</tr></tbody>
</table></div>
</li>
<li class="listitem">
<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Functor<span class="special">></span> <span class="identifier">size_t</span> <a name="id-1_3_23_6_3_1_1_1_11_15-bb"></a><span class="identifier">consume_all</span><span class="special">(</span><span class="identifier">Functor</span> <span class="keyword">const</span> <span class="special">&</span> f<span class="special">)</span><span class="special">;</span></pre>
<p>consumes all elements via a functor</p>
<p>sequentially pops all elements from the queue and applies the functor on each object</p>
<p>
</p>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../doc/src/images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>Thread-safe and non-blocking, if functor is thread-safe and non-blocking </p></td></tr>
</table></div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>number of elements that are consumed</p></td>
</tr></tbody>
</table></div>
</li>
</ol></div>
</div>
</div>
</div>
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<td align="right"><div class="copyright-footer">Copyright © 2008-2011 Tim
Blechmann<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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