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| <h1 align="center">pool_alloc - Boost Pool Standard Allocators |
| Implementation</h1> |
| |
| <h2>Dependencies</h2> |
| |
| <p>Includes the system headers <span class="code"><new></span> and |
| <span class="code"><limits></span>.</p> |
| |
| <p>Includes the Boost headers <span class= |
| "code">"singleton_pool.hpp"</span> (see <a href= |
| "singleton_pool.html">singleton_pool.html</a>) and <span class= |
| "code">"detail/mutex.hpp"</span> (see <a href= |
| "mutex.html">mutex.html</a>).</p> |
| |
| <h2>Synopsis</h2> |
| <pre class="code"> |
| template <typename T, |
| typename UserAllocator = default_user_allocator_new_delete, |
| typename Mutex = details::pool::default_mutex, |
| unsigned NextSize = 32> |
| class pool_allocator |
| { |
| public: |
| ... // public interface |
| |
| public: // extensions to public interface |
| typedef Mutex mutex; |
| static const unsigned next_size = NextSize; |
| |
| template <typename U> |
| struct rebind |
| { |
| typedef pool_allocator<U, UserAllocator, Mutex, NextSize> other; |
| }; |
| }; |
| |
| template <typename T, |
| typename UserAllocator = default_user_allocator_new_delete, |
| typename Mutex = details::pool::default_mutex, |
| unsigned NextSize = 32> |
| class fast_pool_allocator |
| { |
| public: |
| ... // public interface |
| |
| public: // extensions to public interface |
| typedef Mutex mutex; |
| static const unsigned next_size = NextSize; |
| |
| template <typename U> |
| struct rebind |
| { |
| typedef fast_pool_allocator<U, UserAllocator, Mutex, NextSize> other; |
| }; |
| }; |
| </pre> |
| |
| <h2>Extensions to Public Interface</h2> |
| |
| <h3>Additional template parameters</h3> |
| |
| <h4 class="code">Mutex</h4> |
| |
| <p>This parameter allows the user to determine the type of synchronization |
| to be used on the underlying singleton pool. See the extensions to the |
| public interface of <a href="singleton_pool.html">singleton pool</a> for |
| more information.</p> |
| |
| <h4 class="code">NextSize</h4> |
| |
| <p>The value of this parameter is passed to the underlying Pool when it is |
| created. See the extensions to the public interface of <a href= |
| "pool.html">pool</a> for more information.</p> |
| |
| <h3>Modification of <span class="code">rebind</span></h3> |
| |
| <p>The struct <span class="code">rebind</span> has been redefined to |
| preserve the values of the additional template parameters.</p> |
| |
| <h3>Additional members</h3> |
| |
| <p>The typedef <span class="code">mutex</span> and the static const value |
| <span class="code">next_size</span> publish the values of the template |
| parameters <span class="code">Mutex</span> and <span class= |
| "code">NextSize</span>, respectively.</p> |
| |
| <h2>Notes</h2> |
| |
| <p>A number of common STL libraries contain bugs in their using of |
| allocators. Specifically, they pass null pointers to the <span class= |
| "code">deallocate</span> function, which is explicitly forbidden by the |
| Standard [20.1.5 Table 32]. PoolAlloc will work around these libraries if |
| it detects them; currently, workarounds are in place for:</p> |
| |
| <ul> |
| <li>Borland C++ (Builder and command-line compiler) with default |
| (RogueWave) library, ver. 5 and earlier</li> |
| |
| <li>STLport (with any compiler), ver. 4.0 and earlier</li> |
| </ul> |
| |
| <h2>Future Directions</h2> |
| |
| <p>When the Boost multithreading library is completed, the <span class= |
| "code">Mutex</span> parameter will be replaced by something from that |
| library providing the same flexibility and will move from an implementation |
| detail into the interface specification.</p> |
| |
| <h2><a href="../interfaces/pool_alloc.html">Interface Description</a></h2> |
| <hr> |
| |
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| |
| <p>Revised |
| <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->05 |
| December, 2006<!--webbot bot="Timestamp" endspan i-checksum="38516" --></p> |
| |
| <p><i>Copyright © 2000, 2001 Stephen Cleary (scleary AT jerviswebb DOT |
| com)</i></p> |
| |
| <p><i>Distributed under the Boost Software License, Version 1.0. (See |
| accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> |
| or copy at <a href= |
| "http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p> |
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