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diff --git a/doc/html/align/examples.html b/doc/html/align/examples.html index daa0e48afe..d2cd52321e 100644 --- a/doc/html/align/examples.html +++ b/doc/html/align/examples.html @@ -7,7 +7,7 @@ <meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> <link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> <link rel="up" href="../align.html" title="Chapter 4. Boost.Align"> -<link rel="prev" href="tutorial.html" title="Tutorial"> +<link rel="prev" href="rationale.html" title="Rationale"> <link rel="next" href="reference.html" title="Reference"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> @@ -21,122 +21,175 @@ </tr></table> <hr> <div class="spirit-nav"> -<a accesskey="p" href="tutorial.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../align.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="reference.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> +<a accesskey="p" href="rationale.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../align.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="reference.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> </div> <div class="section"> <div class="titlepage"><div><div><h2 class="title" style="clear: both"> <a name="align.examples"></a><a class="link" href="examples.html" title="Examples">Examples</a> </h2></div></div></div> -<div class="toc"><dl class="toc"> -<dt><span class="section"><a href="examples.html#align.examples.aligned_ptr">aligned_ptr and make_aligned</a></span></dt> -<dt><span class="section"><a href="examples.html#align.examples.aligned_vector">aligned_vector</a></span></dt> -</dl></div> -<div class="section"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="align.examples.aligned_ptr"></a><a class="link" href="examples.html#align.examples.aligned_ptr" title="aligned_ptr and make_aligned">aligned_ptr and make_aligned</a> -</h3></div></div></div> +<h4> +<a name="align.examples.h0"></a> + <span class="phrase"><a name="align.examples.aligned_allocation"></a></span><a class="link" href="examples.html#align.examples.aligned_allocation">Aligned + allocation</a> + </h4> <p> - This example presents an alternative to <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span></code> - for objects allocated with the aligned allocation function. It is defined - simply by providing an alias template which uses <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span></code> - with our aligned deleter in place of the default <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">default_delete</span></code> - deleter. It also presents an alternative to <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">make_unique</span></code> - for the creation of these aligned unique pointer objects. It is implemented - using our aligned allocation function. - </p> -<h5> -<a name="align.examples.aligned_ptr.h0"></a> - <span class="phrase"><a name="align.examples.aligned_ptr.implementation"></a></span><a class="link" href="examples.html#align.examples.aligned_ptr.implementation">Implementation</a> - </h5> -<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="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">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="preprocessor">#include</span> <span class="special"><</span><span class="identifier">memory</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">using</span> <span class="identifier">aligned_ptr</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">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_delete</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="special">...</span> <span class="identifier">Args</span><span class="special">></span> -<span class="keyword">inline</span> <span class="identifier">aligned_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> <span class="identifier">make_aligned</span><span class="special">(</span><span class="identifier">Args</span><span class="special">&&...</span> <span class="identifier">args</span><span class="special">)</span> -<span class="special">{</span> - <span class="keyword">auto</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="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="keyword">sizeof</span><span class="special">(</span><span class="identifier">T</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">throw</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">bad_alloc</span><span class="special">();</span> - <span class="special">}</span> - <span class="keyword">try</span> <span class="special">{</span> - <span class="keyword">auto</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">T</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special"><</span><span class="identifier">Args</span><span class="special">>(</span><span class="identifier">args</span><span class="special">)...);</span> - <span class="keyword">return</span> <span class="identifier">aligned_ptr</span><span class="special"><</span><span class="identifier">T</span><span class="special">>(</span><span class="identifier">q</span><span class="special">);</span> - <span class="special">}</span> <span class="keyword">catch</span> <span class="special">(...)</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="keyword">throw</span><span class="special">;</span> - <span class="special">}</span> -<span class="special">}</span> -</pre> -<h5> -<a name="align.examples.aligned_ptr.h1"></a> - <span class="phrase"><a name="align.examples.aligned_ptr.usage"></a></span><a class="link" href="examples.html#align.examples.aligned_ptr.usage">Usage</a> - </h5> -<pre class="programlisting"><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">auto</span> <span class="identifier">p</span> <span class="special">=</span> <span class="identifier">make_aligned</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">reset</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.examples.aligned_vector"></a><a class="link" href="examples.html#align.examples.aligned_vector" title="aligned_vector">aligned_vector</a> -</h3></div></div></div> + To dynamically allocate storage with desired alignment, you can use the <code class="computeroutput"><span class="identifier">aligned_alloc</span></code> function: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> + <code class="computeroutput"><span class="keyword">void</span><span class="special">*</span> + <span class="identifier">storage</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="identifier">alignment</span><span class="special">,</span> + <span class="identifier">size</span><span class="special">);</span></code> + </li></ol></div> <p> - This example presents an alternative to <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span></code> - that can be used with over-aligned types, and allows specifying a minimum - alignment. It is defined simply by providing an alias template which uses - <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span></code> with our aligned allocator. - </p> -<h5> -<a name="align.examples.aligned_vector.h0"></a> - <span class="phrase"><a name="align.examples.aligned_vector.implementation"></a></span><a class="link" href="examples.html#align.examples.aligned_vector.implementation">Implementation</a> - </h5> -<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">template</span><span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</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="number">1</span><span class="special">></span> -<span class="keyword">using</span> <span class="identifier">aligned_vector</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</span><span class="special"><</span><span class="identifier">T</span><span class="special">,</span> <span class="identifier">Alignment</span><span class="special">></span> <span class="special">>;</span> -</pre> -<h5> -<a name="align.examples.aligned_vector.h1"></a> - <span class="phrase"><a name="align.examples.aligned_vector.usage"></a></span><a class="link" href="examples.html#align.examples.aligned_vector.usage">Usage</a> - </h5> -<pre class="programlisting"><span class="keyword">enum</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="identifier">cache_line</span> <span class="special">=</span> <span class="number">64</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">aligned_vector</span><span class="special"><</span><span class="keyword">char</span><span class="special">,</span> <span class="identifier">cache_line</span><span class="special">></span> <span class="identifier">v</span><span class="special">;</span> - <span class="identifier">v</span><span class="special">.</span><span class="identifier">emplace_back</span><span class="special">();</span> -<span class="special">}</span> -</pre> -</div> + To deallocate storage allocated with the <code class="computeroutput"><span class="identifier">aligned_alloc</span></code> + function, use the <code class="computeroutput"><span class="identifier">aligned_free</span></code> + function: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> + <code class="computeroutput"><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">storage</span><span class="special">);</span></code> + </li></ol></div> +<h4> +<a name="align.examples.h1"></a> + <span class="phrase"><a name="align.examples.aligned_allocator"></a></span><a class="link" href="examples.html#align.examples.aligned_allocator">Aligned + allocator</a> + </h4> +<p> + For C++ allocator aware code, you can use the <code class="computeroutput"><span class="identifier">aligned_allocator</span></code> + class template for an allocator that respects over-alignment: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> + <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="identifier">int128_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</span><span class="special"><</span><span class="identifier">int128_t</span><span class="special">></span> + <span class="special">></span> <span class="identifier">vector</span><span class="special">;</span></code> + </li></ol></div> +<p> + This template allows specifying minimum alignment for all dynamic allocations: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> + <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">double</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">double</span><span class="special">,</span> <span class="number">64</span><span class="special">></span> <span class="special">></span> + <span class="identifier">vector</span><span class="special">;</span></code> + </li></ol></div> +<h4> +<a name="align.examples.h2"></a> + <span class="phrase"><a name="align.examples.aligned_allocator_adaptor"></a></span><a class="link" href="examples.html#align.examples.aligned_allocator_adaptor">Aligned + allocator adaptor</a> + </h4> +<p> + To turn an allocator into an allocator that respects over-alignment, you can + use the <code class="computeroutput"><span class="identifier">aligned_allocator_adaptor</span></code> + class template: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"> +<li class="listitem"> + <code class="computeroutput"><span class="identifier">Allocator</span><span class="special"><</span><span class="identifier">int128_t</span><span class="special">></span> + <span class="identifier">first</span><span class="special">;</span></code> + </li> +<li class="listitem"> + <code class="computeroutput"><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">int128_t</span><span class="special">></span> + <span class="special">></span> <span class="identifier">second</span><span class="special">(</span><span class="identifier">first</span><span class="special">);</span></code> + </li> +</ol></div> +<p> + This template allows specifying minimum alignment for all dynamic allocations: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"> +<li class="listitem"> + <code class="computeroutput"><span class="identifier">Allocator</span><span class="special"><</span><span class="keyword">double</span><span class="special">></span> <span class="identifier">first</span><span class="special">;</span></code> + </li> +<li class="listitem"> + <code class="computeroutput"><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="keyword">double</span><span class="special">>,</span> <span class="number">64</span><span class="special">></span> <span class="identifier">second</span><span class="special">(</span><span class="identifier">first</span><span class="special">);</span></code> + </li> +</ol></div> +<h4> +<a name="align.examples.h3"></a> + <span class="phrase"><a name="align.examples.aligned_deleter"></a></span><a class="link" href="examples.html#align.examples.aligned_deleter">Aligned + deleter</a> + </h4> +<p> + For a deleter that can be paired with <code class="computeroutput"><span class="identifier">aligned_alloc</span></code>, + you can use the <code class="computeroutput"><span class="identifier">aligned_delete</span></code> + class: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> + <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">unique_ptr</span><span class="special"><</span><span class="keyword">double</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">pointer</span><span class="special">;</span></code> + </li></ol></div> +<h4> +<a name="align.examples.h4"></a> + <span class="phrase"><a name="align.examples.pointer_alignment"></a></span><a class="link" href="examples.html#align.examples.pointer_alignment">Pointer + alignment</a> + </h4> +<p> + To advance a pointer to the next address with the desired alignment: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"> +<li class="listitem"> + <code class="computeroutput"><span class="keyword">void</span><span class="special">*</span> + <span class="identifier">pointer</span> <span class="special">=</span> + <span class="identifier">storage</span><span class="special">;</span></code> + </li> +<li class="listitem"> + <code class="computeroutput"><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="identifier">size</span><span class="special">;</span></code> + </li> +<li class="listitem"> + <code class="computeroutput"><span class="keyword">void</span><span class="special">*</span> + <span class="identifier">result</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="number">64</span><span class="special">,</span> <span class="keyword">sizeof</span><span class="special">(</span><span class="keyword">double</span><span class="special">),</span> <span class="identifier">pointer</span><span class="special">,</span> <span class="identifier">space</span><span class="special">);</span></code> + </li> +</ol></div> +<h4> +<a name="align.examples.h5"></a> + <span class="phrase"><a name="align.examples.querying_alignment"></a></span><a class="link" href="examples.html#align.examples.querying_alignment">Querying + alignment</a> + </h4> +<p> + To obtain the alignment of a given type at compie time, you can use: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> + <code class="computeroutput"><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">int128_t</span><span class="special">>::</span><span class="identifier">value</span></code> + </li></ol></div> +<p> + If your compiler supports C++14 variable templates, you can also use: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> + <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">alignment</span><span class="special">::</span><span class="identifier">alignment_of_v</span><span class="special"><</span><span class="identifier">int128_t</span><span class="special">></span></code> + </li></ol></div> +<h4> +<a name="align.examples.h6"></a> + <span class="phrase"><a name="align.examples.hinting_alignment"></a></span><a class="link" href="examples.html#align.examples.hinting_alignment">Hinting + alignment</a> + </h4> +<p> + To inform the compiler about the alignment of a pointer, you can use: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> + <code class="computeroutput"><span class="identifier">BOOST_ALIGN_ASSUME_ALIGNED</span><span class="special">(</span><span class="identifier">pointer</span><span class="special">,</span> <span class="number">64</span><span class="special">)</span></code> + </li></ol></div> +<h4> +<a name="align.examples.h7"></a> + <span class="phrase"><a name="align.examples.checking_alignment"></a></span><a class="link" href="examples.html#align.examples.checking_alignment">Checking + alignment</a> + </h4> +<p> + To check alignment of a pointer you can use the <code class="computeroutput"><span class="identifier">is_aligned</span></code> + function: + </p> +<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> + <code class="computeroutput"><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">pointer</span><span class="special">,</span> <span class="number">64</span><span class="special">));</span></code> + </li></ol></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 © 2014-2016 Glen Joseph Fernandes<p> +<td align="right"><div class="copyright-footer">Copyright © 2014-2017 Glen + Joseph Fernandes<p> Distributed under the Boost Software License, Version 1.0. </p> </div></td> </tr></table> <hr> <div class="spirit-nav"> -<a accesskey="p" href="tutorial.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../align.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="reference.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> +<a accesskey="p" href="rationale.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../align.html"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="reference.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html> |