diff options
Diffstat (limited to 'doc/html/boost_asio/overview/core/streams.html')
| -rwxr-xr-x | doc/html/boost_asio/overview/core/streams.html | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/doc/html/boost_asio/overview/core/streams.html b/doc/html/boost_asio/overview/core/streams.html new file mode 100755 index 0000000000..f997143e01 --- /dev/null +++ b/doc/html/boost_asio/overview/core/streams.html @@ -0,0 +1,127 @@ +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> +<title>Streams, Short Reads and Short Writes</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="../core.html" title="Core Concepts and Functionality"> +<link rel="prev" href="buffers.html" title="Buffers"> +<link rel="next" href="reactor.html" title="Reactor-Style Operations"> +</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="buffers.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../core.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="reactor.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +<div class="section"> +<div class="titlepage"><div><div><h4 class="title"> +<a name="boost_asio.overview.core.streams"></a><a class="link" href="streams.html" title="Streams, Short Reads and Short Writes">Streams, Short Reads + and Short Writes</a> +</h4></div></div></div> +<p> + Many I/O objects in Boost.Asio are stream-oriented. This means that: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + There are no message boundaries. The data being transferred is a continuous + sequence of bytes. + </li> +<li class="listitem"> + Read or write operations may transfer fewer bytes than requested. This + is referred to as a short read or short write. + </li> +</ul></div> +<p> + Objects that provide stream-oriented I/O model one or more of the following + type requirements: + </p> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + <code class="computeroutput"><span class="identifier">SyncReadStream</span></code>, where + synchronous read operations are performed using a member function called + <code class="computeroutput"><span class="identifier">read_some</span><span class="special">()</span></code>. + </li> +<li class="listitem"> + <code class="computeroutput"><span class="identifier">AsyncReadStream</span></code>, where + asynchronous read operations are performed using a member function + called <code class="computeroutput"><span class="identifier">async_read_some</span><span class="special">()</span></code>. + </li> +<li class="listitem"> + <code class="computeroutput"><span class="identifier">SyncWriteStream</span></code>, where + synchronous write operations are performed using a member function + called <code class="computeroutput"><span class="identifier">write_some</span><span class="special">()</span></code>. + </li> +<li class="listitem"> + <code class="computeroutput"><span class="identifier">AsyncWriteStream</span></code>, where + synchronous write operations are performed using a member function + called <code class="computeroutput"><span class="identifier">async_write_some</span><span class="special">()</span></code>. + </li> +</ul></div> +<p> + Examples of stream-oriented I/O objects include <code class="computeroutput"><span class="identifier">ip</span><span class="special">::</span><span class="identifier">tcp</span><span class="special">::</span><span class="identifier">socket</span></code>, + <code class="computeroutput"><span class="identifier">ssl</span><span class="special">::</span><span class="identifier">stream</span><span class="special"><></span></code>, + <code class="computeroutput"><span class="identifier">posix</span><span class="special">::</span><span class="identifier">stream_descriptor</span></code>, <code class="computeroutput"><span class="identifier">windows</span><span class="special">::</span><span class="identifier">stream_handle</span></code>, + etc. + </p> +<p> + Programs typically want to transfer an exact number of bytes. When a short + read or short write occurs the program must restart the operation, and + continue to do so until the required number of bytes has been transferred. + Boost.Asio provides generic functions that do this automatically: <code class="computeroutput"><span class="identifier">read</span><span class="special">()</span></code>, + <code class="computeroutput"><span class="identifier">async_read</span><span class="special">()</span></code>, + <code class="computeroutput"><span class="identifier">write</span><span class="special">()</span></code> + and <code class="computeroutput"><span class="identifier">async_write</span><span class="special">()</span></code>. + </p> +<h6> +<a name="boost_asio.overview.core.streams.h0"></a> + <span><a name="boost_asio.overview.core.streams.why_eof_is_an_error"></a></span><a class="link" href="streams.html#boost_asio.overview.core.streams.why_eof_is_an_error">Why EOF + is an Error</a> + </h6> +<div class="itemizedlist"><ul class="itemizedlist" type="disc"> +<li class="listitem"> + The end of a stream can cause <code class="computeroutput"><span class="identifier">read</span></code>, + <code class="computeroutput"><span class="identifier">async_read</span></code>, <code class="computeroutput"><span class="identifier">read_until</span></code> or <code class="computeroutput"><span class="identifier">async_read_until</span></code> + functions to violate their contract. E.g. a read of N bytes may finish + early due to EOF. + </li> +<li class="listitem"> + An EOF error may be used to distinguish the end of a stream from a + successful read of size 0. + </li> +</ul></div> +<h6> +<a name="boost_asio.overview.core.streams.h1"></a> + <span><a name="boost_asio.overview.core.streams.see_also"></a></span><a class="link" href="streams.html#boost_asio.overview.core.streams.see_also">See + Also</a> + </h6> +<p> + <a class="link" href="../../reference/async_read.html" title="async_read">async_read()</a>, <a class="link" href="../../reference/async_write.html" title="async_write">async_write()</a>, <a class="link" href="../../reference/read.html" title="read">read()</a>, <a class="link" href="../../reference/write.html" title="write">write()</a>, + <a class="link" href="../../reference/AsyncReadStream.html" title="Buffer-oriented asynchronous read stream requirements">AsyncReadStream</a>, + <a class="link" href="../../reference/AsyncWriteStream.html" title="Buffer-oriented asynchronous write stream requirements">AsyncWriteStream</a>, + <a class="link" href="../../reference/SyncReadStream.html" title="Buffer-oriented synchronous read stream requirements">SyncReadStream</a>, + <a class="link" href="../../reference/SyncWriteStream.html" title="Buffer-oriented synchronous write stream requirements">SyncWriteStream</a>. + </p> +</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="buffers.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../core.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="reactor.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> +</div> +</body> +</html> |