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| <div class="titlepage"><div><div><h2 class="title" style="clear: both"> |
| <a name="align.tutorial"></a><a class="link" href="tutorial.html" title="Tutorial">Tutorial</a> |
| </h2></div></div></div> |
| <div class="toc"><dl class="toc"> |
| <dt><span class="section"><a href="tutorial.html#align.tutorial.align">align</a></span></dt> |
| <dt><span class="section"><a href="tutorial.html#align.tutorial.aligned_alloc">aligned_alloc and aligned_free</a></span></dt> |
| <dt><span class="section"><a href="tutorial.html#align.tutorial.aligned_allocator">aligned_allocator</a></span></dt> |
| <dt><span class="section"><a href="tutorial.html#align.tutorial.aligned_allocator_adaptor">aligned_allocator_adaptor</a></span></dt> |
| <dt><span class="section"><a href="tutorial.html#align.tutorial.aligned_delete">aligned_delete</a></span></dt> |
| <dt><span class="section"><a href="tutorial.html#align.tutorial.alignment_of">alignment_of</a></span></dt> |
| <dt><span class="section"><a href="tutorial.html#align.tutorial.is_aligned">is_aligned</a></span></dt> |
| </dl></div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="align.tutorial.align"></a><a class="link" href="tutorial.html#align.tutorial.align" title="align">align</a> |
| </h3></div></div></div> |
| <p> |
| The alignment function can be used to find the first address of a given alignment |
| value within a given buffer of a given size. It adjusts the pointer provided, |
| returns that value, and decreases space by the amount advanced, if the alignment |
| succeeds, provided sufficient space in the buffer. Otherwise it yields a |
| null pointer to indicate failure due to insufficient space. |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">align</span><span class="special">/</span><span class="identifier">align</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> |
| <span class="keyword">inline</span> <span class="identifier">T</span><span class="special">*</span> <span class="identifier">make</span><span class="special">(</span><span class="keyword">void</span><span class="special">*</span> <span class="identifier">ptr</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">space</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="keyword">void</span><span class="special">*</span> <span class="identifier">p</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span> |
| <span class="identifier">align</span><span class="special">(</span><span class="keyword">alignof</span><span class="special">(</span><span class="identifier">T</span><span class="special">),</span> <span class="keyword">sizeof</span><span class="special">(</span><span class="identifier">T</span><span class="special">),</span> <span class="identifier">ptr</span><span class="special">,</span> <span class="identifier">space</span><span class="special">);</span> |
| <span class="keyword">if</span> <span class="special">(</span><span class="identifier">p</span><span class="special">)</span> <span class="special">{</span> |
| <span class="keyword">return</span> <span class="special">::</span><span class="keyword">new</span><span class="special">(</span><span class="identifier">p</span><span class="special">)</span> <span class="identifier">T</span><span class="special">();</span> |
| <span class="special">}</span> <span class="keyword">else</span> <span class="special">{</span> |
| <span class="keyword">return</span> <span class="keyword">nullptr</span><span class="special">;</span> |
| <span class="special">}</span> |
| <span class="special">}</span> |
| |
| <span class="keyword">struct</span> <span class="keyword">alignas</span><span class="special">(</span><span class="number">16</span><span class="special">)</span> <span class="identifier">type</span> <span class="special">{</span> |
| <span class="keyword">float</span> <span class="identifier">data</span><span class="special">[</span><span class="number">4</span><span class="special">];</span> |
| <span class="special">};</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="keyword">char</span> <span class="identifier">c</span><span class="special">[</span><span class="number">48</span><span class="special">];</span> |
| <span class="identifier">type</span><span class="special">*</span> <span class="identifier">p</span> <span class="special">=</span> <span class="identifier">make</span><span class="special"><</span><span class="identifier">type</span><span class="special">>(</span><span class="identifier">c</span><span class="special">,</span> <span class="keyword">sizeof</span> <span class="identifier">c</span><span class="special">);</span> |
| <span class="keyword">if</span> <span class="special">(</span><span class="identifier">p</span><span class="special">)</span> <span class="special">{</span> |
| <span class="identifier">p</span><span class="special">->~</span><span class="identifier">type</span><span class="special">();</span> |
| <span class="special">}</span> |
| <span class="special">}</span> |
| </pre> |
| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="align.tutorial.aligned_alloc"></a><a class="link" href="tutorial.html#align.tutorial.aligned_alloc" title="aligned_alloc and aligned_free">aligned_alloc and aligned_free</a> |
| </h3></div></div></div> |
| <p> |
| Consider these functions alignment enabled versions of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">malloc</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span><span class="special">)</span></code> |
| and <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">free</span><span class="special">(</span><span class="keyword">void</span><span class="special">*)</span></code> or <code class="computeroutput"><span class="special">::</span><span class="keyword">operator</span> <span class="keyword">new</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">no_throw_t</span><span class="special">&)</span></code> and <code class="computeroutput"><span class="special">::</span><span class="keyword">operator</span> <span class="keyword">delete</span><span class="special">(</span><span class="keyword">void</span><span class="special">*)</span></code>. |
| The aligned allocation function allocates space with the specified size and |
| alignment. The aligned deallocation function can then deallocate this space. |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">align</span><span class="special">/</span><span class="identifier">aligned_alloc</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| |
| <span class="keyword">void</span> <span class="identifier">use</span><span class="special">(</span><span class="keyword">void</span><span class="special">*</span> <span class="identifier">ptr</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="identifier">ptr</span><span class="special">;</span> |
| <span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="identifier">size</span><span class="special">;</span> |
| <span class="special">}</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="keyword">void</span><span class="special">*</span> <span class="identifier">p</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span><span class="identifier">aligned_alloc</span><span class="special">(</span><span class="number">16</span><span class="special">,</span> <span class="number">100</span><span class="special">);</span> |
| <span class="keyword">if</span> <span class="special">(</span><span class="identifier">p</span><span class="special">)</span> <span class="special">{</span> |
| <span class="identifier">use</span><span class="special">(</span><span class="identifier">p</span><span class="special">,</span> <span class="number">100</span><span class="special">);</span> |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span><span class="identifier">aligned_free</span><span class="special">(</span><span class="identifier">p</span><span class="special">);</span> |
| <span class="special">}</span> |
| <span class="special">}</span> |
| </pre> |
| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="align.tutorial.aligned_allocator"></a><a class="link" href="tutorial.html#align.tutorial.aligned_allocator" title="aligned_allocator">aligned_allocator</a> |
| </h3></div></div></div> |
| <p> |
| Consider this class template a superior version of the default allocator, |
| <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">allocator</span></code>, because it can be used with |
| types that are over-aligned. |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">align</span><span class="special">/</span><span class="identifier">aligned_allocator</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">vector</span><span class="special">></span> |
| |
| <span class="keyword">struct</span> <span class="keyword">alignas</span><span class="special">(</span><span class="number">16</span><span class="special">)</span> <span class="identifier">type</span> <span class="special">{</span> |
| <span class="keyword">float</span> <span class="identifier">data</span><span class="special">[</span><span class="number">4</span><span class="special">];</span> |
| <span class="special">};</span> |
| |
| <span class="keyword">void</span> <span class="identifier">use</span><span class="special">(</span><span class="identifier">type</span><span class="special">*</span> <span class="identifier">ptr</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="identifier">ptr</span><span class="special">;</span> |
| <span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="identifier">size</span><span class="special">;</span> |
| <span class="special">}</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">type</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span> |
| <span class="identifier">aligned_allocator</span><span class="special"><</span><span class="identifier">type</span><span class="special">></span> <span class="special">></span> <span class="identifier">v</span><span class="special">(</span><span class="number">100</span><span class="special">);</span> |
| <span class="identifier">use</span><span class="special">(&</span><span class="identifier">v</span><span class="special">[</span><span class="number">0</span><span class="special">],</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">size</span><span class="special">());</span> |
| <span class="special">}</span> |
| </pre> |
| <p> |
| The optional template parameter of this class allows specifying a minimum |
| alignment to use for allocations. The default minimum alignment is 1. |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">align</span><span class="special">/</span><span class="identifier">aligned_allocator</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">vector</span><span class="special">></span> |
| |
| <span class="keyword">void</span> <span class="identifier">use</span><span class="special">(</span><span class="keyword">char</span><span class="special">*</span> <span class="identifier">ptr</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="identifier">ptr</span><span class="special">;</span> |
| <span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="identifier">size</span><span class="special">;</span> |
| <span class="special">}</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">char</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span> |
| <span class="identifier">aligned_allocator</span><span class="special"><</span><span class="keyword">char</span><span class="special">,</span> <span class="number">16</span><span class="special">></span> <span class="special">></span> <span class="identifier">v</span><span class="special">(</span><span class="number">100</span><span class="special">);</span> |
| <span class="identifier">use</span><span class="special">(&</span><span class="identifier">v</span><span class="special">[</span><span class="number">0</span><span class="special">],</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">size</span><span class="special">());</span> |
| <span class="special">}</span> |
| </pre> |
| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="align.tutorial.aligned_allocator_adaptor"></a><a class="link" href="tutorial.html#align.tutorial.aligned_allocator_adaptor" title="aligned_allocator_adaptor">aligned_allocator_adaptor</a> |
| </h3></div></div></div> |
| <p> |
| This class template can turn any existing allocator type, C++11 or C++03, |
| stateful or stateless, into one that supports types which are over-aligned. |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">align</span><span class="special">/</span><span class="identifier">aligned_allocator_adaptor</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">vector</span><span class="special">></span> |
| |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Allocator</span><span class="special">></span> |
| <span class="keyword">class</span> <span class="identifier">utility</span> <span class="special">{</span> |
| <span class="keyword">public</span><span class="special">:</span> |
| <span class="identifier">utility</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">)</span> |
| <span class="special">:</span> <span class="identifier">v</span><span class="special">(</span><span class="identifier">size</span><span class="special">)</span> <span class="special">{</span> |
| <span class="special">}</span> |
| <span class="keyword">private</span><span class="special">:</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">T</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span> |
| <span class="identifier">aligned_allocator_adaptor</span><span class="special"><</span><span class="identifier">Allocator</span><span class="special">></span> <span class="special">></span> <span class="identifier">v</span><span class="special">;</span> |
| <span class="special">};</span> |
| |
| <span class="keyword">struct</span> <span class="keyword">alignas</span><span class="special">(</span><span class="number">16</span><span class="special">)</span> <span class="identifier">type</span> <span class="special">{</span> |
| <span class="keyword">float</span> <span class="identifier">data</span><span class="special">[</span><span class="number">4</span><span class="special">];</span> |
| <span class="special">};</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="identifier">utility</span><span class="special"><</span><span class="identifier">type</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">allocator</span><span class="special"><</span><span class="identifier">type</span><span class="special">></span> <span class="special">></span> <span class="identifier">u</span><span class="special">(</span><span class="number">100</span><span class="special">);</span> |
| <span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="identifier">u</span><span class="special">;</span> |
| <span class="special">}</span> |
| </pre> |
| <p> |
| The optional template parameter of this class allows specifying a minimum |
| alignment to use for allocations. The default minimum alignment is 1. |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">align</span><span class="special">/</span><span class="identifier">aligned_allocator_adaptor</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">vector</span><span class="special">></span> |
| |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Allocator</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">Alignment</span><span class="special">></span> |
| <span class="keyword">class</span> <span class="identifier">utility</span> <span class="special">{</span> |
| <span class="keyword">public</span><span class="special">:</span> |
| <span class="identifier">utility</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">)</span> |
| <span class="special">:</span> <span class="identifier">v</span><span class="special">(</span><span class="identifier">size</span><span class="special">)</span> <span class="special">{</span> |
| <span class="special">}</span> |
| <span class="keyword">private</span><span class="special">:</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">T</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span> |
| <span class="identifier">aligned_allocator_adaptor</span><span class="special"><</span><span class="identifier">Allocator</span><span class="special">,</span> <span class="identifier">Alignment</span><span class="special">></span> <span class="special">></span> <span class="identifier">v</span><span class="special">;</span> |
| <span class="special">};</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="identifier">utility</span><span class="special"><</span><span class="keyword">char</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">allocator</span><span class="special"><</span><span class="keyword">char</span><span class="special">>,</span> <span class="number">16</span><span class="special">></span> <span class="identifier">u</span><span class="special">(</span><span class="number">100</span><span class="special">);</span> |
| <span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="identifier">u</span><span class="special">;</span> |
| <span class="special">}</span> |
| </pre> |
| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="align.tutorial.aligned_delete"></a><a class="link" href="tutorial.html#align.tutorial.aligned_delete" title="aligned_delete">aligned_delete</a> |
| </h3></div></div></div> |
| <p> |
| Consider this class an alignment aware version of the <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">default_delete</span></code> |
| deleter class template. It is a deleter that destroys the object and then |
| deallocates space using our aligned deallocation function. It should be used |
| with constructed objects that were allocated with our aligned allocation |
| function and is useful with deleter enabled types like <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span></code>. |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">align</span><span class="special">/</span><span class="identifier">aligned_delete</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">memory</span><span class="special">></span> |
| |
| <span class="keyword">struct</span> <span class="keyword">alignas</span><span class="special">(</span><span class="number">16</span><span class="special">)</span> <span class="identifier">type</span> <span class="special">{</span> |
| <span class="keyword">float</span> <span class="identifier">data</span><span class="special">[</span><span class="number">4</span><span class="special">];</span> |
| <span class="special">};</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="keyword">void</span><span class="special">*</span> <span class="identifier">p</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span> |
| <span class="identifier">aligned_alloc</span><span class="special">(</span><span class="keyword">alignof</span><span class="special">(</span><span class="identifier">type</span><span class="special">),</span> <span class="keyword">sizeof</span><span class="special">(</span><span class="identifier">type</span><span class="special">));</span> |
| <span class="keyword">if</span> <span class="special">(</span><span class="identifier">p</span><span class="special">)</span> <span class="special">{</span> |
| <span class="identifier">type</span><span class="special">*</span> <span class="identifier">q</span> <span class="special">=</span> <span class="special">::</span><span class="keyword">new</span><span class="special">(</span><span class="identifier">p</span><span class="special">)</span> <span class="identifier">type</span><span class="special">();</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span><span class="special"><</span><span class="identifier">type</span><span class="special">,</span> |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span><span class="identifier">aligned_delete</span><span class="special">></span> <span class="identifier">u</span><span class="special">(</span><span class="identifier">q</span><span class="special">);</span> |
| <span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="identifier">u</span><span class="special">;</span> |
| <span class="special">}</span> |
| <span class="special">}</span> |
| </pre> |
| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="align.tutorial.alignment_of"></a><a class="link" href="tutorial.html#align.tutorial.alignment_of" title="alignment_of">alignment_of</a> |
| </h3></div></div></div> |
| <p> |
| This type trait can be used to query the alignment requirement of a type |
| at compile time. It is useful in static assertions to validate type alignment. |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">align</span><span class="special">/</span><span class="identifier">alignment_of</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| |
| <span class="keyword">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> |
| <span class="keyword">class</span> <span class="identifier">utility</span> <span class="special">{</span> |
| <span class="keyword">static_assert</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span> |
| <span class="identifier">alignment_of</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">value</span> <span class="special">==</span> <span class="number">16</span><span class="special">,</span> <span class="string">""</span><span class="special">);</span> |
| <span class="keyword">public</span><span class="special">:</span> |
| <span class="identifier">utility</span><span class="special">()</span> |
| <span class="special">:</span> <span class="identifier">object</span><span class="special">()</span> <span class="special">{</span> |
| <span class="special">}</span> |
| <span class="keyword">private</span><span class="special">:</span> |
| <span class="identifier">T</span> <span class="identifier">object</span><span class="special">;</span> |
| <span class="special">};</span> |
| |
| <span class="keyword">struct</span> <span class="keyword">alignas</span><span class="special">(</span><span class="number">16</span><span class="special">)</span> <span class="identifier">type</span> <span class="special">{</span> |
| <span class="keyword">float</span> <span class="identifier">data</span><span class="special">[</span><span class="number">4</span><span class="special">];</span> |
| <span class="special">};</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="identifier">utility</span><span class="special"><</span><span class="identifier">type</span><span class="special">></span> <span class="identifier">u</span><span class="special">;</span> |
| <span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="identifier">u</span><span class="special">;</span> |
| <span class="special">}</span> |
| </pre> |
| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="align.tutorial.is_aligned"></a><a class="link" href="tutorial.html#align.tutorial.is_aligned" title="is_aligned">is_aligned</a> |
| </h3></div></div></div> |
| <p> |
| This function is used to compare the alignment of a pointer. It is useful |
| in assertions that validate a pointer value is aligned on a given boundary. |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">align</span><span class="special">/</span><span class="identifier">is_aligned</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">cassert</span><span class="special">></span> |
| |
| <span class="keyword">void</span> <span class="identifier">use</span><span class="special">(</span><span class="keyword">void</span><span class="special">*</span> <span class="identifier">ptr</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">size</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="identifier">assert</span><span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span><span class="identifier">is_aligned</span><span class="special">(</span><span class="identifier">ptr</span><span class="special">,</span> <span class="number">16</span><span class="special">));</span> |
| <span class="special">(</span><span class="keyword">void</span><span class="special">)</span><span class="identifier">size</span><span class="special">;</span> |
| <span class="special">}</span> |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> |
| <span class="special">{</span> |
| <span class="keyword">alignas</span><span class="special">(</span><span class="number">16</span><span class="special">)</span> <span class="keyword">char</span> <span class="identifier">c</span><span class="special">[</span><span class="number">100</span><span class="special">];</span> |
| <span class="identifier">use</span><span class="special">(</span><span class="identifier">c</span><span class="special">,</span> <span class="keyword">sizeof</span> <span class="identifier">c</span><span class="special">);</span> |
| <span class="special">}</span> |
| </pre> |
| </div> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2014 Glen Fernandes<p> |
| Distributed under the <a href="http://boost.org/LICENSE_1_0.txt" target="_top">Boost |
| Software License, Version 1.0</a>. |
| </p> |
| </div></td> |
| </tr></table> |
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