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diff --git a/libstdc++-v3/doc/html/manual/strings.html b/libstdc++-v3/doc/html/manual/strings.html index 73b9a7fc01b..82df2a751d5 100644 --- a/libstdc++-v3/doc/html/manual/strings.html +++ b/libstdc++-v3/doc/html/manual/strings.html @@ -1,14 +1,14 @@ <?xml version="1.0" encoding="UTF-8" standalone="no"?> -<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> -<html xmlns="http://www.w3.org/1999/xhtml"><head><title>Chapter 7. Strings</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.76.1"/><meta name="keywords" content=" ISO C++ , library "/><meta name="keywords" content=" ISO C++ , runtime , library "/><link rel="home" href="../index.html" title="The GNU C++ Library"/><link rel="up" href="bk01pt02.html" title="Part II. Standard Contents"/><link rel="prev" href="traits.html" title="Traits"/><link rel="next" href="localization.html" title="Chapter 8. Localization"/></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 7. +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Chapter 7. Strings</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.76.1" /><meta name="keywords" content=" ISO C++ , library " /><meta name="keywords" content=" ISO C++ , runtime , library " /><link rel="home" href="../index.html" title="The GNU C++ Library" /><link rel="up" href="bk01pt02.html" title="Part II. Standard Contents" /><link rel="prev" href="traits.html" title="Traits" /><link rel="next" href="localization.html" title="Chapter 8. Localization" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 7. Strings -</th></tr><tr><td align="left"><a accesskey="p" href="traits.html">Prev</a> </td><th width="60%" align="center">Part II. +</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="traits.html">Prev</a> </td><th width="60%" align="center">Part II. Standard Contents - </th><td align="right"> <a accesskey="n" href="localization.html">Next</a></td></tr></table><hr/></div><div class="chapter" title="Chapter 7. Strings"><div class="titlepage"><div><div><h2 class="title"><a id="std.strings"/>Chapter 7. + </th><td width="20%" align="right"> <a accesskey="n" href="localization.html">Next</a></td></tr></table><hr /></div><div class="chapter" title="Chapter 7. Strings"><div class="titlepage"><div><div><h2 class="title"><a id="std.strings"></a>Chapter 7. Strings - <a id="id499563" class="indexterm"/> -</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl><dt><span class="section"><a href="strings.html#std.strings.string">String Classes</a></span></dt><dd><dl><dt><span class="section"><a href="strings.html#strings.string.simple">Simple Transformations</a></span></dt><dt><span class="section"><a href="strings.html#strings.string.case">Case Sensitivity</a></span></dt><dt><span class="section"><a href="strings.html#strings.string.character_types">Arbitrary Character Types</a></span></dt><dt><span class="section"><a href="strings.html#strings.string.token">Tokenizing</a></span></dt><dt><span class="section"><a href="strings.html#strings.string.shrink">Shrink to Fit</a></span></dt><dt><span class="section"><a href="strings.html#strings.string.Cstring">CString (MFC)</a></span></dt></dl></dd></dl></div><div class="section" title="String Classes"><div class="titlepage"><div><div><h2 class="title"><a id="std.strings.string"/>String Classes</h2></div></div></div><div class="section" title="Simple Transformations"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.simple"/>Simple Transformations</h3></div></div></div><p> + <a id="idp15576144" class="indexterm"></a> +</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl><dt><span class="section"><a href="strings.html#std.strings.string">String Classes</a></span></dt><dd><dl><dt><span class="section"><a href="strings.html#strings.string.simple">Simple Transformations</a></span></dt><dt><span class="section"><a href="strings.html#strings.string.case">Case Sensitivity</a></span></dt><dt><span class="section"><a href="strings.html#strings.string.character_types">Arbitrary Character Types</a></span></dt><dt><span class="section"><a href="strings.html#strings.string.token">Tokenizing</a></span></dt><dt><span class="section"><a href="strings.html#strings.string.shrink">Shrink to Fit</a></span></dt><dt><span class="section"><a href="strings.html#strings.string.Cstring">CString (MFC)</a></span></dt></dl></dd></dl></div><div class="section" title="String Classes"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="std.strings.string"></a>String Classes</h2></div></div></div><div class="section" title="Simple Transformations"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.simple"></a>Simple Transformations</h3></div></div></div><p> Here are Standard, simple, and portable ways to perform common transformations on a <code class="code">string</code> instance, such as "convert to all upper case." The word transformations @@ -64,7 +64,7 @@ are overloaded names (declared in <code class="code"><cctype></code> and <code class="code"><locale></code>) so the template-arguments for <code class="code">transform<></code> cannot be deduced, as explained in - <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-11/msg00180.html">this + <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-11/msg00180.html" target="_top">this message</a>. At minimum, you can write short wrappers like @@ -89,9 +89,9 @@ str.erase(notwhite+1); </pre><p>Obviously, the calls to <code class="code">find</code> could be inserted directly into the calls to <code class="code">erase</code>, in case your compiler does not optimize named temporaries out of existence. - </p></div><div class="section" title="Case Sensitivity"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.case"/>Case Sensitivity</h3></div></div></div><p> + </p></div><div class="section" title="Case Sensitivity"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.case"></a>Case Sensitivity</h3></div></div></div><p> </p><p>The well-known-and-if-it-isn't-well-known-it-ought-to-be - <a class="link" href="http://www.gotw.ca/gotw/">Guru of the Week</a> + <a class="link" href="http://www.gotw.ca/gotw/" target="_top">Guru of the Week</a> discussions held on Usenet covered this topic in January of 1998. Briefly, the challenge was, <span class="quote">“<span class="quote">write a 'ci_string' class which is identical to the standard 'string' class, but is @@ -108,10 +108,10 @@ assert( strcmp( s.c_str(), "AbCdE" ) == 0 ); assert( strcmp( s.c_str(), "abcde" ) != 0 ); </pre><p>The solution is surprisingly easy. The original answer was posted on Usenet, and a revised version appears in Herb Sutter's - book <span class="emphasis"><em>Exceptional C++</em></span> and on his website as <a class="link" href="http://www.gotw.ca/gotw/029.htm">GotW 29</a>. + book <span class="emphasis"><em>Exceptional C++</em></span> and on his website as <a class="link" href="http://www.gotw.ca/gotw/029.htm" target="_top">GotW 29</a>. </p><p>See? Told you it was easy!</p><p> <span class="emphasis"><em>Added June 2000:</em></span> The May 2000 issue of C++ - Report contains a fascinating <a class="link" href="http://lafstern.org/matt/col2_new.pdf"> article</a> by + Report contains a fascinating <a class="link" href="http://lafstern.org/matt/col2_new.pdf" target="_top"> article</a> by Matt Austern (yes, <span class="emphasis"><em>the</em></span> Matt Austern) on why case-insensitive comparisons are not as easy as they seem, and why creating a class is the <span class="emphasis"><em>wrong</em></span> way to go @@ -123,10 +123,10 @@ that nobody ever called me on it...) The GotW question and answer remain useful instructional tools, however. </p><p><span class="emphasis"><em>Added September 2000:</em></span> James Kanze provided a link to a - <a class="link" href="http://www.unicode.org/reports/tr21/tr21-5.html">Unicode + <a class="link" href="http://www.unicode.org/reports/tr21/tr21-5.html" target="_top">Unicode Technical Report discussing case handling</a>, which provides some very good information. - </p></div><div class="section" title="Arbitrary Character Types"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.character_types"/>Arbitrary Character Types</h3></div></div></div><p> + </p></div><div class="section" title="Arbitrary Character Types"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.character_types"></a>Arbitrary Character Types</h3></div></div></div><p> </p><p>The <code class="code">std::basic_string</code> is tantalizingly general, in that it is parameterized on the type of the characters which it holds. In theory, you could whip up a Unicode character class and instantiate @@ -169,18 +169,18 @@ works and can be specialized even for <code class="code">int</code> and other built-in types. </p><p>If you want to use your own special character class, then you have - <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-08/msg00163.html">a lot + <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-08/msg00163.html" target="_top">a lot of work to do</a>, especially if you with to use i18n features (facets require traits information but don't have a traits argument). - </p><p>Another example of how to specialize char_traits was given <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-08/msg00260.html">on the + </p><p>Another example of how to specialize char_traits was given <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-08/msg00260.html" target="_top">on the mailing list</a> and at a later date was put into the file <code class="code"> include/ext/pod_char_traits.h</code>. We agree that the way it's used with basic_string (scroll down to main()) - doesn't look nice, but that's because <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-08/msg00236.html">the - nice-looking first attempt</a> turned out to <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-08/msg00242.html">not + doesn't look nice, but that's because <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-08/msg00236.html" target="_top">the + nice-looking first attempt</a> turned out to <a class="link" href="http://gcc.gnu.org/ml/libstdc++/2002-08/msg00242.html" target="_top">not be conforming C++</a>, due to the rule that CharT must be a POD. (See how tricky this is?) - </p></div><div class="section" title="Tokenizing"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.token"/>Tokenizing</h3></div></div></div><p> + </p></div><div class="section" title="Tokenizing"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.token"></a>Tokenizing</h3></div></div></div><p> </p><p>The Standard C (and C++) function <code class="code">strtok()</code> leaves a lot to be desired in terms of user-friendliness. It's unintuitive, it destroys the character string on which it operates, and it requires @@ -256,7 +256,7 @@ stringtok(Container &container, string const &in, tokenizing as well. Build an istringstream from the input text, and then use std::getline with varying delimiters (the three-argument signature) to extract tokens into a string. - </p></div><div class="section" title="Shrink to Fit"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.shrink"/>Shrink to Fit</h3></div></div></div><p> + </p></div><div class="section" title="Shrink to Fit"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.shrink"></a>Shrink to Fit</h3></div></div></div><p> </p><p>From GCC 3.4 calling <code class="code">s.reserve(res)</code> on a <code class="code">string s</code> with <code class="code">res < s.capacity()</code> will reduce the string's capacity to <code class="code">std::max(s.size(), res)</code>. @@ -272,7 +272,7 @@ stringtok(Container &container, string const &in, </p><p>In <a class="link" href="status.html#status.iso.2011" title="C++ 2011">C++11</a> mode you can call <code class="code">s.shrink_to_fit()</code> to achieve the same effect as <code class="code">s.reserve(s.size())</code>. - </p></div><div class="section" title="CString (MFC)"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.Cstring"/>CString (MFC)</h3></div></div></div><p> + </p></div><div class="section" title="CString (MFC)"><div class="titlepage"><div><div><h3 class="title"><a id="strings.string.Cstring"></a>CString (MFC)</h3></div></div></div><p> </p><p>A common lament seen in various newsgroups deals with the Standard string class as opposed to the Microsoft Foundation Class called CString. Often programmers realize that a standard portable @@ -280,9 +280,9 @@ stringtok(Container &container, string const &in, their application from a Win32 platform, they discover that they are relying on special functions offered by the CString class. </p><p>Things are not as bad as they seem. In - <a class="link" href="http://gcc.gnu.org/ml/gcc/1999-04n/msg00236.html">this + <a class="link" href="http://gcc.gnu.org/ml/gcc/1999-04n/msg00236.html" target="_top">this message</a>, Joe Buck points out a few very important things: - </p><div class="itemizedlist"><ul class="itemizedlist"><li class="listitem"><p>The Standard <code class="code">string</code> supports all the operations + </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>The Standard <code class="code">string</code> supports all the operations that CString does, with three exceptions. </p></li><li class="listitem"><p>Two of those exceptions (whitespace trimming and case conversion) are trivial to implement. In fact, we do so @@ -340,7 +340,7 @@ stringtok(Container &container, string const &in, performance is O(n). </pre><p>Joe Buck also pointed out some other things to keep in mind when comparing CString and the Standard string class: - </p><div class="itemizedlist"><ul class="itemizedlist"><li class="listitem"><p>CString permits access to its internal representation; coders + </p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><p>CString permits access to its internal representation; coders who exploited that may have problems moving to <code class="code">string</code>. </p></li><li class="listitem"><p>Microsoft ships the source to CString (in the files MFC\SRC\Str{core,ex}.cpp), so you could fix the allocation @@ -360,7 +360,7 @@ stringtok(Container &container, string const &in, libstdc++ string, the SGI string, and the SGI rope, and this is all before any allocator or traits customizations! (More choices than you can shake a stick at -- want fries with that?) - </p></li></ul></div></div></div></div><div class="navfooter"><hr/><table width="100%" summary="Navigation footer"><tr><td align="left"><a accesskey="p" href="traits.html">Prev</a> </td><td align="center"><a accesskey="u" href="bk01pt02.html">Up</a></td><td align="right"> <a accesskey="n" href="localization.html">Next</a></td></tr><tr><td align="left" valign="top">Traits </td><td align="center"><a accesskey="h" href="../index.html">Home</a></td><td align="right" valign="top"> Chapter 8. + </p></li></ul></div></div></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="traits.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="bk01pt02.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="localization.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Traits </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 8. 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