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27 <a name="beast.ref.boost__beast__basic_stream.async_write_some"></a><a class="link" href="async_write_some.html" title="basic_stream::async_write_some">basic_stream::async_write_some</a>
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30 <a class="indexterm" name="idm45873516385808"></a>
31 Write some data asynchronously.
34 <a name="beast.ref.boost__beast__basic_stream.async_write_some.h0"></a>
35 <span class="phrase"><a name="beast.ref.boost__beast__basic_stream.async_write_some.synopsis"></a></span><a class="link" href="async_write_some.html#beast.ref.boost__beast__basic_stream.async_write_some.synopsis">Synopsis</a>
37 <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span>
38 <span class="keyword">class</span> <a href="../../../../../../../doc/html/boost_asio/reference/ConstBufferSequence.html" target="_top"><span class="emphasis"><em>ConstBufferSequence</em></span></a><span class="special">,</span>
39 <span class="keyword">class</span> <a href="../../../../../../../doc/html/boost_asio/reference/WriteHandler.html" target="_top"><span class="emphasis"><em>WriteHandler</em></span></a> <span class="special">=</span> <span class="identifier">net</span><span class="special">::</span><span class="identifier">default_completion_token_t</span><span class="special"><</span><span class="identifier">Executor</span><span class="special">>></span>
40 <a href="../../../../../../../doc/html/boost_asio/reference/asynchronous_operations.html#boost_asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type" target="_top"><span class="emphasis"><em>DEDUCED</em></span></a>
41 <span class="identifier">async_write_some</span><span class="special">(</span>
42 <span class="identifier">ConstBufferSequence</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">buffers</span><span class="special">,</span>
43 <span class="identifier">WriteHandler</span><span class="special">&&</span> <span class="identifier">handler</span> <span class="special">=</span> <span class="identifier">net</span><span class="special">::</span><span class="identifier">default_completion_token_t</span><span class="special"><</span> <span class="identifier">Executor</span> <span class="special">>{});</span>
46 <a name="beast.ref.boost__beast__basic_stream.async_write_some.h1"></a>
47 <span class="phrase"><a name="beast.ref.boost__beast__basic_stream.async_write_some.description"></a></span><a class="link" href="async_write_some.html#beast.ref.boost__beast__basic_stream.async_write_some.description">Description</a>
50 This function is used to asynchronously write data to the underlying socket.
51 This call always returns immediately. The asynchronous operation will continue
52 until one of the following conditions is true:
54 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
56 One or more bytes are written to the stream.
63 The algorithm, known as a <span class="emphasis"><em>composed asynchronous operation</em></span>,
64 is implemented in terms of calls to the next layer's <code class="computeroutput"><span class="identifier">async_write_some</span></code>
65 function. The program must ensure that no other calls to <a class="link" href="async_write_some.html" title="basic_stream::async_write_some"><code class="computeroutput"><span class="identifier">basic_stream</span><span class="special">::</span><span class="identifier">async_write_some</span></code></a> are performed
66 until this operation completes. If the timeout timer expires while the
67 operation is outstanding, the operation will be canceled and the completion
68 handler will be invoked with the error <a class="link" href="../boost__beast__error.html" title="error"><code class="computeroutput"><span class="identifier">timeout</span></code></a>.
71 <a name="beast.ref.boost__beast__basic_stream.async_write_some.h2"></a>
72 <span class="phrase"><a name="beast.ref.boost__beast__basic_stream.async_write_some.parameters"></a></span><a class="link" href="async_write_some.html#beast.ref.boost__beast__basic_stream.async_write_some.parameters">Parameters</a>
74 <div class="informaltable"><table class="table">
95 <code class="computeroutput"><span class="identifier">buffers</span></code>
100 The buffers from which the data will be written. If the size
101 of the buffers is zero bytes, the operation always completes
102 immediately with no error. Although the buffers object may be
103 copied as necessary, ownership of the underlying memory blocks
104 is retained by the caller, which must guarantee that they remain
105 valid until the handler is called.
112 <code class="computeroutput"><span class="identifier">handler</span></code>
117 The completion handler to invoke when the operation completes.
118 The implementation takes ownership of the handler by performing
119 a decay-copy. The equivalent function signature of the handler
122 <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span>
123 <span class="identifier">error_code</span> <span class="identifier">error</span><span class="special">,</span> <span class="comment">// Result of operation.</span>
124 <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>
125 <span class="special">);</span>
128 Regardless of whether the asynchronous operation completes immediately
129 or not, the handler will not be invoked from within this function.
130 Invocation of the handler will be performed in a manner equivalent
131 to using <code class="computeroutput"><span class="identifier">net</span><span class="special">::</span><span class="identifier">post</span></code>.
138 <a name="beast.ref.boost__beast__basic_stream.async_write_some.h3"></a>
139 <span class="phrase"><a name="beast.ref.boost__beast__basic_stream.async_write_some.remarks"></a></span><a class="link" href="async_write_some.html#beast.ref.boost__beast__basic_stream.async_write_some.remarks">Remarks</a>
142 The <code class="computeroutput"><span class="identifier">async_write_some</span></code> operation
143 may not transmit all of the requested number of bytes. Consider using the
144 function <code class="computeroutput"><span class="identifier">net</span><span class="special">::</span><span class="identifier">async_write</span></code> if you need to ensure that
145 the requested amount of data is sent before the asynchronous operation
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