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| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="boost_asio.overview.implementation"></a><a class="link" href="implementation.html" title="Platform-Specific Implementation Notes">Platform-Specific |
| Implementation Notes</a> |
| </h3></div></div></div> |
| <p> |
| This section lists platform-specific implementation details, such as the |
| default demultiplexing mechanism, the number of threads created internally, |
| and when threads are created. |
| </p> |
| <h5> |
| <a name="boost_asio.overview.implementation.h0"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.linux_kernel_2_4"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.linux_kernel_2_4">Linux |
| Kernel 2.4</a> |
| </h5> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Uses <code class="computeroutput"><span class="identifier">select</span></code> for demultiplexing. |
| This means that the number of file descriptors in the process cannot |
| be permitted to exceed <code class="computeroutput"><span class="identifier">FD_SETSIZE</span></code>. |
| </li></ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Demultiplexing using <code class="computeroutput"><span class="identifier">select</span></code> |
| is performed in one of the threads that calls <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run_one</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll_one</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to emulate asynchronous host resolution. This thread is created |
| on the first call to either <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">udp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| At most <code class="computeroutput"><span class="identifier">min</span><span class="special">(</span><span class="number">64</span><span class="special">,</span><span class="identifier">IOV_MAX</span><span class="special">)</span></code> buffers may be transferred in a single |
| operation. |
| </li></ul></div> |
| <h5> |
| <a name="boost_asio.overview.implementation.h1"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.linux_kernel_2_6"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.linux_kernel_2_6">Linux |
| Kernel 2.6</a> |
| </h5> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Uses <code class="computeroutput"><span class="identifier">epoll</span></code> for demultiplexing. |
| </li></ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Demultiplexing using <code class="computeroutput"><span class="identifier">epoll</span></code> |
| is performed in one of the threads that calls <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run_one</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll_one</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to emulate asynchronous host resolution. This thread is created |
| on the first call to either <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">udp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| At most <code class="computeroutput"><span class="identifier">min</span><span class="special">(</span><span class="number">64</span><span class="special">,</span><span class="identifier">IOV_MAX</span><span class="special">)</span></code> buffers may be transferred in a single |
| operation. |
| </li></ul></div> |
| <h5> |
| <a name="boost_asio.overview.implementation.h2"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.solaris"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.solaris">Solaris</a> |
| </h5> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Uses <code class="literal">/dev/poll</code> for demultiplexing. |
| </li></ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Demultiplexing using <code class="literal">/dev/poll</code> is performed in one |
| of the threads that calls <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run_one</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll_one</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to emulate asynchronous host resolution. This thread is created |
| on the first call to either <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">udp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| At most <code class="computeroutput"><span class="identifier">min</span><span class="special">(</span><span class="number">64</span><span class="special">,</span><span class="identifier">IOV_MAX</span><span class="special">)</span></code> buffers may be transferred in a single |
| operation. |
| </li></ul></div> |
| <h5> |
| <a name="boost_asio.overview.implementation.h3"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.qnx_neutrino"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.qnx_neutrino">QNX |
| Neutrino</a> |
| </h5> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Uses <code class="computeroutput"><span class="identifier">select</span></code> for demultiplexing. |
| This means that the number of file descriptors in the process cannot |
| be permitted to exceed <code class="computeroutput"><span class="identifier">FD_SETSIZE</span></code>. |
| </li></ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Demultiplexing using <code class="computeroutput"><span class="identifier">select</span></code> |
| is performed in one of the threads that calls <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run_one</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll_one</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to emulate asynchronous host resolution. This thread is created |
| on the first call to either <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">udp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| At most <code class="computeroutput"><span class="identifier">min</span><span class="special">(</span><span class="number">64</span><span class="special">,</span><span class="identifier">IOV_MAX</span><span class="special">)</span></code> buffers may be transferred in a single |
| operation. |
| </li></ul></div> |
| <h5> |
| <a name="boost_asio.overview.implementation.h4"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.mac_os_x"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.mac_os_x">Mac |
| OS X</a> |
| </h5> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Uses <code class="computeroutput"><span class="identifier">kqueue</span></code> for demultiplexing. |
| </li></ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Demultiplexing using <code class="computeroutput"><span class="identifier">kqueue</span></code> |
| is performed in one of the threads that calls <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run_one</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll_one</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to emulate asynchronous host resolution. This thread is created |
| on the first call to either <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">udp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| At most <code class="computeroutput"><span class="identifier">min</span><span class="special">(</span><span class="number">64</span><span class="special">,</span><span class="identifier">IOV_MAX</span><span class="special">)</span></code> buffers may be transferred in a single |
| operation. |
| </li></ul></div> |
| <h5> |
| <a name="boost_asio.overview.implementation.h5"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.freebsd"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.freebsd">FreeBSD</a> |
| </h5> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Uses <code class="computeroutput"><span class="identifier">kqueue</span></code> for demultiplexing. |
| </li></ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Demultiplexing using <code class="computeroutput"><span class="identifier">kqueue</span></code> |
| is performed in one of the threads that calls <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run_one</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll_one</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to emulate asynchronous host resolution. This thread is created |
| on the first call to either <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">udp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| At most <code class="computeroutput"><span class="identifier">min</span><span class="special">(</span><span class="number">64</span><span class="special">,</span><span class="identifier">IOV_MAX</span><span class="special">)</span></code> buffers may be transferred in a single |
| operation. |
| </li></ul></div> |
| <h5> |
| <a name="boost_asio.overview.implementation.h6"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.aix"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.aix">AIX</a> |
| </h5> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Uses <code class="computeroutput"><span class="identifier">select</span></code> for demultiplexing. |
| This means that the number of file descriptors in the process cannot |
| be permitted to exceed <code class="computeroutput"><span class="identifier">FD_SETSIZE</span></code>. |
| </li></ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Demultiplexing using <code class="computeroutput"><span class="identifier">select</span></code> |
| is performed in one of the threads that calls <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run_one</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll_one</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to emulate asynchronous host resolution. This thread is created |
| on the first call to either <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">udp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| At most <code class="computeroutput"><span class="identifier">min</span><span class="special">(</span><span class="number">64</span><span class="special">,</span><span class="identifier">IOV_MAX</span><span class="special">)</span></code> buffers may be transferred in a single |
| operation. |
| </li></ul></div> |
| <h5> |
| <a name="boost_asio.overview.implementation.h7"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.hp_ux"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.hp_ux">HP-UX</a> |
| </h5> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Uses <code class="computeroutput"><span class="identifier">select</span></code> for demultiplexing. |
| This means that the number of file descriptors in the process cannot |
| be permitted to exceed <code class="computeroutput"><span class="identifier">FD_SETSIZE</span></code>. |
| </li></ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Demultiplexing using <code class="computeroutput"><span class="identifier">select</span></code> |
| is performed in one of the threads that calls <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run_one</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll_one</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to emulate asynchronous host resolution. This thread is created |
| on the first call to either <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">udp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| At most <code class="computeroutput"><span class="identifier">min</span><span class="special">(</span><span class="number">64</span><span class="special">,</span><span class="identifier">IOV_MAX</span><span class="special">)</span></code> buffers may be transferred in a single |
| operation. |
| </li></ul></div> |
| <h5> |
| <a name="boost_asio.overview.implementation.h8"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.tru64"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.tru64">Tru64</a> |
| </h5> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Uses <code class="computeroutput"><span class="identifier">select</span></code> for demultiplexing. |
| This means that the number of file descriptors in the process cannot |
| be permitted to exceed <code class="computeroutput"><span class="identifier">FD_SETSIZE</span></code>. |
| </li></ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Demultiplexing using <code class="computeroutput"><span class="identifier">select</span></code> |
| is performed in one of the threads that calls <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run_one</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll_one</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to emulate asynchronous host resolution. This thread is created |
| on the first call to either <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">udp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| At most <code class="computeroutput"><span class="identifier">min</span><span class="special">(</span><span class="number">64</span><span class="special">,</span><span class="identifier">IOV_MAX</span><span class="special">)</span></code> buffers may be transferred in a single |
| operation. |
| </li></ul></div> |
| <h5> |
| <a name="boost_asio.overview.implementation.h9"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.windows_95__98_and_me"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.windows_95__98_and_me">Windows |
| 95, 98 and Me</a> |
| </h5> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Uses <code class="computeroutput"><span class="identifier">select</span></code> for demultiplexing. |
| </li></ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Demultiplexing using <code class="computeroutput"><span class="identifier">select</span></code> |
| is performed in one of the threads that calls <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run_one</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll_one</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to emulate asynchronous host resolution. This thread is created |
| on the first call to either <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">udp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| For sockets, at most 16 buffers may be transferred in a single operation. |
| </li></ul></div> |
| <h5> |
| <a name="boost_asio.overview.implementation.h10"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.windows_nt__2000__xp__2003__vista__7_and_8"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.windows_nt__2000__xp__2003__vista__7_and_8">Windows |
| NT, 2000, XP, 2003, Vista, 7 and 8</a> |
| </h5> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Uses overlapped I/O and I/O completion ports for all asynchronous socket |
| operations except for asynchronous connect. |
| </li> |
| <li class="listitem"> |
| Uses <code class="computeroutput"><span class="identifier">select</span></code> for emulating |
| asynchronous connect. |
| </li> |
| </ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Demultiplexing using I/O completion ports is performed in all threads |
| that call <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">run_one</span><span class="special">()</span></code>, <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">poll_one</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to trigger timers. This thread is created on construction of |
| the first <code class="computeroutput"><span class="identifier">deadline_timer</span></code> |
| or <code class="computeroutput"><span class="identifier">deadline_timer_service</span></code> |
| objects. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used for the <code class="computeroutput"><span class="identifier">select</span></code> |
| demultiplexing. This thread is created on the first call to <code class="computeroutput"><span class="identifier">async_connect</span><span class="special">()</span></code>. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to emulate asynchronous host resolution. This thread is created |
| on the first call to either <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code> or <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">udp</span><span class="special">::</span><span class="identifier">resolver</span><span class="special">::</span><span class="identifier">async_resolve</span><span class="special">()</span></code>. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| For sockets, at most 64 buffers may be transferred in a single operation. |
| </li> |
| <li class="listitem"> |
| For stream-oriented handles, only one buffer may be transferred in a |
| single operation. |
| </li> |
| </ul></div> |
| <h5> |
| <a name="boost_asio.overview.implementation.h11"></a> |
| <span class="phrase"><a name="boost_asio.overview.implementation.windows_runtime"></a></span><a class="link" href="implementation.html#boost_asio.overview.implementation.windows_runtime">Windows |
| Runtime</a> |
| </h5> |
| <p> |
| Boost.Asio provides limited support for the Windows Runtime. It requires |
| that the language extensions be enabled. Due to the restricted facilities |
| exposed by the Windows Runtime API, the support comes with the following |
| caveats: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| The core facilities such as the <code class="computeroutput"><span class="identifier">io_service</span></code>, |
| <code class="computeroutput"><span class="identifier">strand</span></code>, buffers, composed |
| operations, timers, etc., should all work as normal. |
| </li> |
| <li class="listitem"> |
| For sockets, only client-side TCP is supported. |
| </li> |
| <li class="listitem"> |
| Explicit binding of a client-side TCP socket is not supported. |
| </li> |
| <li class="listitem"> |
| The <code class="computeroutput"><span class="identifier">cancel</span><span class="special">()</span></code> |
| function is not supported for sockets. Asynchronous operations may only |
| be cancelled by closing the socket. |
| </li> |
| <li class="listitem"> |
| Operations that use <code class="computeroutput"><span class="identifier">null_buffers</span></code> |
| are not supported. |
| </li> |
| <li class="listitem"> |
| Only <code class="computeroutput"><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">no_delay</span></code> and <code class="computeroutput"><span class="identifier">socket_base</span><span class="special">::</span><span class="identifier">keep_alive</span></code> |
| options are supported. |
| </li> |
| <li class="listitem"> |
| Resolvers do not support service names, only numbers. I.e. you must use |
| "80" rather than "http". |
| </li> |
| <li class="listitem"> |
| Most resolver query flags have no effect. |
| </li> |
| </ul></div> |
| <p> |
| Demultiplexing mechanism: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| Uses the <code class="computeroutput"><span class="identifier">Windows</span><span class="special">::</span><span class="identifier">Networking</span><span class="special">::</span><span class="identifier">Sockets</span><span class="special">::</span><span class="identifier">StreamSocket</span></code> class to implement asynchronous |
| TCP socket operations. |
| </li></ul></div> |
| <p> |
| Threads: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> |
| <li class="listitem"> |
| Event completions are delivered to the Windows thread pool and posted |
| to the <code class="computeroutput"><span class="identifier">io_service</span></code> for |
| the handler to be executed. |
| </li> |
| <li class="listitem"> |
| An additional thread per <code class="computeroutput"><span class="identifier">io_service</span></code> |
| is used to trigger timers. This thread is created on construction of |
| the first timer objects. |
| </li> |
| </ul></div> |
| <p> |
| Scatter-Gather: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"> |
| For sockets, at most one buffer may be transferred in a single operation. |
| </li></ul></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 © 2003-2015 Christopher M. |
| Kohlhoff<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>) |
| </p> |
| </div></td> |
| </tr></table> |
| <hr> |
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