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  26 <div class="titlepage"><div><div><h4 class="title">
  27 <a name="boost_asio.reference.windows__basic_random_access_handle.async_write_some_at"></a><a class="link" href="async_write_some_at.html" title="windows::basic_random_access_handle::async_write_some_at">windows::basic_random_access_handle::async_write_some_at</a>
  28 </h4></div></div></div>
  29 <p>
  30           <a class="indexterm" name="idp175938688"></a>
  31 Start an asynchronous
  32           write at the specified offset.
  33         </p>
  34 <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
  35     <span class="keyword">typename</span> <a class="link" href="../ConstBufferSequence.html" title="Constant buffer sequence requirements">ConstBufferSequence</a><span class="special">,</span>
  36     <span class="keyword">typename</span> <a class="link" href="../WriteHandler.html" title="Write handler requirements">WriteHandler</a><span class="special">&gt;</span>
  37 <a class="link" href="../asynchronous_operations.html#boost_asio.reference.asynchronous_operations.return_type_of_an_initiating_function"><span class="emphasis"><em>void-or-deduced</em></span></a> <span class="identifier">async_write_some_at</span><span class="special">(</span>
  38     <span class="identifier">uint64_t</span> <span class="identifier">offset</span><span class="special">,</span>
  39     <span class="keyword">const</span> <span class="identifier">ConstBufferSequence</span> <span class="special">&amp;</span> <span class="identifier">buffers</span><span class="special">,</span>
  40     <span class="identifier">WriteHandler</span> <span class="identifier">handler</span><span class="special">);</span>
  41 </pre>
  42 <p>
  43           This function is used to asynchronously write data to the random-access
  44           handle. The function call always returns immediately.
  45         </p>
  46 <h6>
  47 <a name="boost_asio.reference.windows__basic_random_access_handle.async_write_some_at.h0"></a>
  48           <span class="phrase"><a name="boost_asio.reference.windows__basic_random_access_handle.async_write_some_at.parameters"></a></span><a class="link" href="async_write_some_at.html#boost_asio.reference.windows__basic_random_access_handle.async_write_some_at.parameters">Parameters</a>
  49         </h6>
  50 <div class="variablelist">
  51 <p class="title"><b></b></p>
  52 <dl class="variablelist">
  53 <dt><span class="term">offset</span></dt>
  54 <dd><p>
  55                 The offset at which the data will be written.
  56               </p></dd>
  57 <dt><span class="term">buffers</span></dt>
  58 <dd><p>
  59                 One or more data buffers to be written to the handle. Although the
  60                 buffers object may be copied as necessary, ownership of the underlying
  61                 memory blocks is retained by the caller, which must guarantee that
  62                 they remain valid until the handler is called.
  63               </p></dd>
  64 <dt><span class="term">handler</span></dt>
  65 <dd>
  66 <p>
  67                 The handler to be called when the write operation completes. Copies
  68                 will be made of the handler as required. The function signature of
  69                 the handler must be:
  70 </p>
  71 <pre class="programlisting"><span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span>
  72   <span class="keyword">const</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">error_code</span><span class="special">&amp;</span> <span class="identifier">error</span><span class="special">,</span> <span class="comment">// Result of operation.</span>
  73   <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">bytes_transferred</span>           <span class="comment">// Number of bytes written.</span>
  74 <span class="special">);</span>
  75 </pre>
  76 <p>
  77                 Regardless of whether the asynchronous operation completes immediately
  78                 or not, the handler will not be invoked from within this function.
  79                 Invocation of the handler will be performed in a manner equivalent
  80                 to using <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">io_service</span><span class="special">::</span><span class="identifier">post</span><span class="special">()</span></code>.
  81               </p>
  82 </dd>
  83 </dl>
  84 </div>
  85 <h6>
  86 <a name="boost_asio.reference.windows__basic_random_access_handle.async_write_some_at.h1"></a>
  87           <span class="phrase"><a name="boost_asio.reference.windows__basic_random_access_handle.async_write_some_at.remarks"></a></span><a class="link" href="async_write_some_at.html#boost_asio.reference.windows__basic_random_access_handle.async_write_some_at.remarks">Remarks</a>
  88         </h6>
  89 <p>
  90           The write operation may not transmit all of the data to the peer. Consider
  91           using the <a class="link" href="../async_write_at.html" title="async_write_at"><code class="computeroutput"><span class="identifier">async_write_at</span></code></a> function if you
  92           need to ensure that all data is written before the asynchronous operation
  93           completes.
  94         </p>
  95 <h6>
  96 <a name="boost_asio.reference.windows__basic_random_access_handle.async_write_some_at.h2"></a>
  97           <span class="phrase"><a name="boost_asio.reference.windows__basic_random_access_handle.async_write_some_at.example"></a></span><a class="link" href="async_write_some_at.html#boost_asio.reference.windows__basic_random_access_handle.async_write_some_at.example">Example</a>
  98         </h6>
  99 <p>
 100           To write a single data buffer use the <a class="link" href="../buffer.html" title="buffer"><code class="computeroutput"><span class="identifier">buffer</span></code></a> function as follows:
 101         </p>
 102 <pre class="programlisting"><span class="identifier">handle</span><span class="special">.</span><span class="identifier">async_write_some_at</span><span class="special">(</span><span class="number">42</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">(</span><span class="identifier">data</span><span class="special">,</span> <span class="identifier">size</span><span class="special">),</span> <span class="identifier">handler</span><span class="special">);</span>
 103 </pre>
 104 <p>
 105           See the <a class="link" href="../buffer.html" title="buffer"><code class="computeroutput"><span class="identifier">buffer</span></code></a>
 106           documentation for information on writing multiple buffers in one go, and
 107           how to use it with arrays, boost::array or std::vector.
 108         </p>
 109 </div>
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