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| author | Anas Nashif <anas.nashif@intel.com> | 2012-10-30 12:57:26 -0700 |
|---|---|---|
| committer | Anas Nashif <anas.nashif@intel.com> | 2012-10-30 12:57:26 -0700 |
| commit | 1a78a62555be32868418fe52f8e330c9d0f95d5a (patch) | |
| tree | d3765a80e7d3b9640ec2e930743630cd6b9fce2b /doc/html/boost_asio/reference/basic_datagram_socket/native_non_blocking/overload1.html | |
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Imported Upstream version 1.49.0upstream/1.49.0
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diff --git a/doc/html/boost_asio/reference/basic_datagram_socket/native_non_blocking/overload1.html b/doc/html/boost_asio/reference/basic_datagram_socket/native_non_blocking/overload1.html new file mode 100755 index 0000000000..01de45a1fb --- /dev/null +++ b/doc/html/boost_asio/reference/basic_datagram_socket/native_non_blocking/overload1.html @@ -0,0 +1,152 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>basic_datagram_socket::native_non_blocking (1 of 3 overloads)</title> +<link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css"> +<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> +<link rel="home" href="../../../../boost_asio.html" title="Boost.Asio"> +<link rel="up" href="../native_non_blocking.html" title="basic_datagram_socket::native_non_blocking"> +<link rel="prev" href="../native_non_blocking.html" title="basic_datagram_socket::native_non_blocking"> +<link rel="next" href="overload2.html" title="basic_datagram_socket::native_non_blocking (2 of 3 overloads)"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> +<table cellpadding="2" width="100%"><tr> +<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td> +<td align="center"><a href="../../../../../../index.html">Home</a></td> +<td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td> +<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> +<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> +<td align="center"><a href="../../../../../../more/index.htm">More</a></td> +</tr></table> +<hr> +<div class="spirit-nav"> +<a accesskey="p" href="../native_non_blocking.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../native_non_blocking.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../boost_asio.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="overload2.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +<div class="section"> +<div class="titlepage"><div><div><h5 class="title"> +<a name="boost_asio.reference.basic_datagram_socket.native_non_blocking.overload1"></a><a class="link" href="overload1.html" title="basic_datagram_socket::native_non_blocking (1 of 3 overloads)">basic_datagram_socket::native_non_blocking + (1 of 3 overloads)</a> +</h5></div></div></div> +<p> + <span class="emphasis"><em>Inherited from basic_socket.</em></span> + </p> +<p> + Gets the non-blocking mode of the native socket implementation. + </p> +<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">native_non_blocking</span><span class="special">()</span> <span class="keyword">const</span><span class="special">;</span> +</pre> +<p> + This function is used to retrieve the non-blocking mode of the underlying + native socket. This mode has no effect on the behaviour of the socket + object's synchronous operations. + </p> +<h6> +<a name="boost_asio.reference.basic_datagram_socket.native_non_blocking.overload1.h0"></a> + <span><a name="boost_asio.reference.basic_datagram_socket.native_non_blocking.overload1.return_value"></a></span><a class="link" href="overload1.html#boost_asio.reference.basic_datagram_socket.native_non_blocking.overload1.return_value">Return + Value</a> + </h6> +<p> + <code class="computeroutput"><span class="keyword">true</span></code> if the underlying socket + is in non-blocking mode and direct system calls may fail with <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">error</span><span class="special">::</span><span class="identifier">would_block</span></code> (or the equivalent system + error). + </p> +<h6> +<a name="boost_asio.reference.basic_datagram_socket.native_non_blocking.overload1.h1"></a> + <span><a name="boost_asio.reference.basic_datagram_socket.native_non_blocking.overload1.remarks"></a></span><a class="link" href="overload1.html#boost_asio.reference.basic_datagram_socket.native_non_blocking.overload1.remarks">Remarks</a> + </h6> +<p> + The current non-blocking mode is cached by the socket object. Consequently, + the return value may be incorrect if the non-blocking mode was set directly + on the native socket. + </p> +<h6> +<a name="boost_asio.reference.basic_datagram_socket.native_non_blocking.overload1.h2"></a> + <span><a name="boost_asio.reference.basic_datagram_socket.native_non_blocking.overload1.example"></a></span><a class="link" href="overload1.html#boost_asio.reference.basic_datagram_socket.native_non_blocking.overload1.example">Example</a> + </h6> +<p> + This function is intended to allow the encapsulation of arbitrary non-blocking + system calls as asynchronous operations, in a way that is transparent + to the user of the socket object. The following example illustrates how + Linux's <code class="computeroutput"><span class="identifier">sendfile</span></code> system + call might be encapsulated: + </p> +<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Handler</span><span class="special">></span> +<span class="keyword">struct</span> <span class="identifier">sendfile_op</span> +<span class="special">{</span> + <span class="identifier">tcp</span><span class="special">::</span><span class="identifier">socket</span><span class="special">&</span> <span class="identifier">sock_</span><span class="special">;</span> + <span class="keyword">int</span> <span class="identifier">fd_</span><span class="special">;</span> + <span class="identifier">Handler</span> <span class="identifier">handler_</span><span class="special">;</span> + <span class="identifier">off_t</span> <span class="identifier">offset_</span><span class="special">;</span> + <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">total_bytes_transferred_</span><span class="special">;</span> + + <span class="comment">// Function call operator meeting WriteHandler requirements.</span> + <span class="comment">// Used as the handler for the async_write_some operation.</span> + <span class="keyword">void</span> <span class="keyword">operator</span><span class="special">()(</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="identifier">ec</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="special">{</span> + <span class="comment">// Put the underlying socket into non-blocking mode.</span> + <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">ec</span><span class="special">)</span> + <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">sock_</span><span class="special">.</span><span class="identifier">native_non_blocking</span><span class="special">())</span> + <span class="identifier">sock_</span><span class="special">.</span><span class="identifier">native_non_blocking</span><span class="special">(</span><span class="keyword">true</span><span class="special">,</span> <span class="identifier">ec</span><span class="special">);</span> + + <span class="keyword">if</span> <span class="special">(!</span><span class="identifier">ec</span><span class="special">)</span> + <span class="special">{</span> + <span class="keyword">for</span> <span class="special">(;;)</span> + <span class="special">{</span> + <span class="comment">// Try the system call.</span> + <span class="identifier">errno</span> <span class="special">=</span> <span class="number">0</span><span class="special">;</span> + <span class="keyword">int</span> <span class="identifier">n</span> <span class="special">=</span> <span class="special">::</span><span class="identifier">sendfile</span><span class="special">(</span><span class="identifier">sock_</span><span class="special">.</span><span class="identifier">native_handle</span><span class="special">(),</span> <span class="identifier">fd_</span><span class="special">,</span> <span class="special">&</span><span class="identifier">offset_</span><span class="special">,</span> <span class="number">65536</span><span class="special">);</span> + <span class="identifier">ec</span> <span class="special">=</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">(</span><span class="identifier">n</span> <span class="special"><</span> <span class="number">0</span> <span class="special">?</span> <span class="identifier">errno</span> <span class="special">:</span> <span class="number">0</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">error</span><span class="special">::</span><span class="identifier">get_system_category</span><span class="special">());</span> + <span class="identifier">total_bytes_transferred_</span> <span class="special">+=</span> <span class="identifier">ec</span> <span class="special">?</span> <span class="number">0</span> <span class="special">:</span> <span class="identifier">n</span><span class="special">;</span> + + <span class="comment">// Retry operation immediately if interrupted by signal.</span> + <span class="keyword">if</span> <span class="special">(</span><span class="identifier">ec</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">error</span><span class="special">::</span><span class="identifier">interrupted</span><span class="special">)</span> + <span class="keyword">continue</span><span class="special">;</span> + + <span class="comment">// Check if we need to run the operation again.</span> + <span class="keyword">if</span> <span class="special">(</span><span class="identifier">ec</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">error</span><span class="special">::</span><span class="identifier">would_block</span> + <span class="special">||</span> <span class="identifier">ec</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">error</span><span class="special">::</span><span class="identifier">try_again</span><span class="special">)</span> + <span class="special">{</span> + <span class="comment">// We have to wait for the socket to become ready again.</span> + <span class="identifier">sock_</span><span class="special">.</span><span class="identifier">async_write_some</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">null_buffers</span><span class="special">(),</span> <span class="special">*</span><span class="keyword">this</span><span class="special">);</span> + <span class="keyword">return</span><span class="special">;</span> + <span class="special">}</span> + + <span class="keyword">if</span> <span class="special">(</span><span class="identifier">ec</span> <span class="special">||</span> <span class="identifier">n</span> <span class="special">==</span> <span class="number">0</span><span class="special">)</span> + <span class="special">{</span> + <span class="comment">// An error occurred, or we have reached the end of the file.</span> + <span class="comment">// Either way we must exit the loop so we can call the handler.</span> + <span class="keyword">break</span><span class="special">;</span> + <span class="special">}</span> + + <span class="comment">// Loop around to try calling sendfile again.</span> + <span class="special">}</span> + <span class="special">}</span> + + <span class="comment">// Pass result back to user's handler.</span> + <span class="identifier">handler_</span><span class="special">(</span><span class="identifier">ec</span><span class="special">,</span> <span class="identifier">total_bytes_transferred_</span><span class="special">);</span> + <span class="special">}</span> +<span class="special">};</span> + +<span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Handler</span><span class="special">></span> +<span class="keyword">void</span> <span class="identifier">async_sendfile</span><span class="special">(</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">socket</span><span class="special">&</span> <span class="identifier">sock</span><span class="special">,</span> <span class="keyword">int</span> <span class="identifier">fd</span><span class="special">,</span> <span class="identifier">Handler</span> <span class="identifier">h</span><span class="special">)</span> +<span class="special">{</span> + <span class="identifier">sendfile_op</span><span class="special"><</span><span class="identifier">Handler</span><span class="special">></span> <span class="identifier">op</span> <span class="special">=</span> <span class="special">{</span> <span class="identifier">sock</span><span class="special">,</span> <span class="identifier">fd</span><span class="special">,</span> <span class="identifier">h</span><span class="special">,</span> <span class="number">0</span><span class="special">,</span> <span class="number">0</span> <span class="special">};</span> + <span class="identifier">sock</span><span class="special">.</span><span class="identifier">async_write_some</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">null_buffers</span><span class="special">(),</span> <span class="identifier">op</span><span class="special">);</span> +<span class="special">}</span> +</pre> +</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 © 2003-2012 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> +<div class="spirit-nav"> +<a accesskey="p" href="../native_non_blocking.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../native_non_blocking.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../boost_asio.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="overload2.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +</body> +</html> |