1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Chapter 26. Memory Based Streams</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><meta name="keywords" content=" ISO C++ , library " /><link rel="home" href="../spine.html" title="The GNU C++ Library Documentation" /><link rel="up" href="io.html" title="Part XI. Input and Output" /><link rel="prev" href="bk01pt11ch25s02.html" title="Buffering" /><link rel="next" href="fstreams.html" title="Chapter 27. File Based Streams" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 26. Memory Based Streams</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="bk01pt11ch25s02.html">Prev</a> </td><th width="60%" align="center">Part XI. 4 Input and Output 5 6</th><td width="20%" align="right"> <a accesskey="n" href="fstreams.html">Next</a></td></tr></table><hr /></div><div class="chapter" title="Chapter 26. Memory Based Streams"><div class="titlepage"><div><div><h2 class="title"><a id="manual.io.memstreams"></a>Chapter 26. Memory Based Streams</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="stringstreams.html#manual.io.memstreams.compat">Compatibility With strstream</a></span></dt></dl></div><div class="sect1" title="Compatibility With strstream"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="manual.io.memstreams.compat"></a>Compatibility With strstream</h2></div></div></div><p> 7 </p><p>Stringstreams (defined in the header <code class="code"><sstream></code>) 8 are in this author's opinion one of the coolest things since 9 sliced time. An example of their use is in the Received Wisdom 10 section for Chapter 21 (Strings), 11 <a class="link" href="bk01pt05ch13s06.html" title="CString (MFC)"> describing how to 12 format strings</a>. 13 </p><p>The quick definition is: they are siblings of ifstream and ofstream, 14 and they do for <code class="code">std::string</code> what their siblings do for 15 files. All that work you put into writing <code class="code"><<</code> and 16 <code class="code">>></code> functions for your classes now pays off 17 <span class="emphasis"><em>again!</em></span> Need to format a string before passing the string 18 to a function? Send your stuff via <code class="code"><<</code> to an 19 ostringstream. You've read a string as input and need to parse it? 20 Initialize an istringstream with that string, and then pull pieces 21 out of it with <code class="code">>></code>. Have a stringstream and need to 22 get a copy of the string inside? Just call the <code class="code">str()</code> 23 member function. 24 </p><p>This only works if you've written your 25 <code class="code"><<</code>/<code class="code">>></code> functions correctly, though, 26 and correctly means that they take istreams and ostreams as 27 parameters, not i<span class="emphasis"><em>f</em></span>streams and o<span class="emphasis"><em>f</em></span>streams. If they 28 take the latter, then your I/O operators will work fine with 29 file streams, but with nothing else -- including stringstreams. 30 </p><p>If you are a user of the strstream classes, you need to update 31 your code. You don't have to explicitly append <code class="code">ends</code> to 32 terminate the C-style character array, you don't have to mess with 33 "freezing" functions, and you don't have to manage the 34 memory yourself. The strstreams have been officially deprecated, 35 which means that 1) future revisions of the C++ Standard won't 36 support them, and 2) if you use them, people will laugh at you. 37 </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="bk01pt11ch25s02.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="io.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="fstreams.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Buffering </td><td width="20%" align="center"><a accesskey="h" href="../spine.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 27. File Based Streams</td></tr></table></div></body></html> 38