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This removes unnecessary whitespace following <pre> blocks in the HTML output. libstdc++-v3/ChangeLog: * doc/xml/faq.xml: Remove unwanted whitespace inside programlisting elements. * doc/xml/manual/allocator.xml: Likewise. * doc/xml/manual/auto_ptr.xml: Likewise. * doc/xml/manual/backwards_compatibility.xml: Likewise. * doc/xml/manual/build_hacking.xml: Likewise. * doc/xml/manual/containers.xml: Likewise. * doc/xml/manual/diagnostics.xml: Likewise. * doc/xml/manual/extensions.xml: Likewise. * doc/xml/manual/intro.xml: Likewise. * doc/xml/manual/io.xml: Likewise. * doc/xml/manual/iterators.xml: Likewise. * doc/xml/manual/numerics.xml: Likewise. * doc/xml/manual/policy_data_structures.xml: Likewise. * doc/xml/manual/strings.xml: Likewise. * doc/xml/manual/support.xml: Likewise. * doc/xml/manual/test.xml: Likewise. * doc/xml/manual/using.xml: Likewise. * doc/xml/manual/utilities.xml: Likewise. * doc/html/*: Regenerate.
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567 lines
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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!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>Backwards Compatibility</title><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><meta name="keywords" content="ISO C++, backwards" /><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="appendix_porting.html" title="Appendix B. Porting and Maintenance" /><link rel="prev" href="api.html" title="API Evolution and Deprecation History" /><link rel="next" href="appendix_free.html" title="Appendix C. Free Software Needs Free Documentation" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Backwards Compatibility</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="api.html">Prev</a> </td><th width="60%" align="center">Appendix B.
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Porting and Maintenance
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</th><td width="20%" align="right"> <a accesskey="n" href="appendix_free.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="manual.appendix.porting.backwards"></a>Backwards Compatibility</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="backwards.first"></a>First</h3></div></div></div><p>The first generation GNU C++ library was called libg++. It was a
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separate GNU project, although reliably paired with GCC. Rumors imply
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that it had a working relationship with at least two kinds of
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dinosaur.
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</p><p>Some background: libg++ was designed and created when there was no
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ISO standard to provide guidance. Classes like linked lists are now
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provided for by <code class="classname">std::list<T></code> and do not need to be
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created by <code class="function">genclass</code>. (For that matter, templates exist
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now and are well-supported, whereas genclass (mostly) predates them.)
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</p><p>There are other classes in libg++ that are not specified in the
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ISO Standard (e.g., statistical analysis). While there are a lot of
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really useful things that are used by a lot of people, the Standards
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||
Committee couldn't include everything, and so a lot of those
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<span class="quote">“<span class="quote">obvious</span>”</span> classes didn't get included.
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</p><p>That project is no longer maintained or supported, and the sources
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archived. For the desperate, the
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<a class="link" href="https://ftp.gnu.org/old-gnu/libg++/" target="_top">ftp.gnu.org</a>
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server still has the libg++ source.
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</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="backwards.second"></a>Second</h3></div></div></div><p>
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The second generation GNU C++ library was called libstdc++, or
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libstdc++-v2. It spans the time between libg++ and pre-ISO C++
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standardization and is usually associated with the following GCC
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releases: egcs 1.x, gcc 2.95, and gcc 2.96.
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</p><p>
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The STL portions of that library are based on SGI/HP STL release 3.11.
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</p><p>
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That project is no longer maintained or supported, and the sources
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archived. The code was replaced and rewritten for libstdc++-v3.
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</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="backwards.third"></a>Third</h3></div></div></div><p> The third generation GNU C++ library is called libstdc++, or
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libstdc++-v3.
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</p><p>The subset commonly known as the Standard Template Library
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(clauses 23 through 25 in C++98, mostly) is adapted from the final release
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of the SGI STL (version 3.3), with extensive changes.
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</p><p>A more formal description of the V3 goals can be found in the
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official <a class="link" href="source_design_notes.html" title="Design Notes">design document</a>.
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</p><p>Portability notes and known implementation limitations are as follows.</p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="backwards.third.headers"></a>Pre-ISO headers removed</h4></div></div></div><p> The pre-ISO C++ headers
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(<code class="filename"><iostream.h></code>,
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<code class="filename"><defalloc.h></code> etc.) are
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not supported.
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</p><p>For those of you new to ISO C++ (welcome, time travelers!), the
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ancient pre-ISO headers have new names.
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The C++ FAQ has a good explanation in <a class="link" href="https://isocpp.org/wiki/faq/coding-standards#std-headers" target="_top">What's
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the difference between <xxx> and <xxx.h> headers?</a>.
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</p><p>Porting between pre-ISO headers and ISO headers is simple: headers
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like <code class="filename"><vector.h></code> can be replaced with <code class="filename"><vector></code> and a using
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directive <code class="code">using namespace std;</code> can be put at the global
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scope. This should be enough to get this code compiling, assuming the
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other usage is correct.
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</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="backwards.third.hash"></a>Extension headers hash_map, hash_set moved to ext or backwards</h4></div></div></div><p>At this time most of the features of the SGI STL extension have been
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replaced by standardized libraries.
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In particular, the <code class="classname">unordered_map</code> and
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<code class="classname">unordered_set</code> containers of TR1 and C++ 2011
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are suitable replacements for the non-standard
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<code class="classname">hash_map</code> and <code class="classname">hash_set</code>
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containers in the SGI STL.
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</p><p> Header files <code class="filename"><hash_map></code> and <code class="filename"><hash_set></code> moved
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to <code class="filename"><ext/hash_map></code> and <code class="filename"><ext/hash_set></code>,
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respectively. At the same time, all types in these files are enclosed
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in <code class="code">namespace __gnu_cxx</code>. Later versions deprecate
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these files, and suggest using TR1's <code class="filename"><unordered_map></code>
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and <code class="filename"><unordered_set></code> instead.
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</p><p>The extensions are no longer in the global or <code class="code">std</code>
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namespaces, instead they are declared in the <code class="code">__gnu_cxx</code>
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namespace. For maximum portability, consider defining a namespace
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alias to use to talk about extensions, e.g.:
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</p><pre class="programlisting">
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#ifdef __GNUC__
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#if __GNUC__ < 3
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#include <hash_map.h>
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namespace extension { using ::hash_map; }; // inherit globals
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#else
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#include <backward/hash_map>
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#if __GNUC__ == 3 && __GNUC_MINOR__ == 0
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namespace extension = std; // GCC 3.0
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#else
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namespace extension = ::__gnu_cxx; // GCC 3.1 and later
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#endif
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#endif
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#else // ... there are other compilers, right?
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namespace extension = std;
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#endif
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extension::hash_map<int,int> my_map;
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</pre><p>This is a bit cleaner than defining typedefs for all the
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instantiations you might need.
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</p><p>The following autoconf tests check for working HP/SGI hash containers.
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</p><pre class="programlisting">
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# AC_HEADER_EXT_HASH_MAP
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AC_DEFUN([AC_HEADER_EXT_HASH_MAP], [
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AC_CACHE_CHECK(for ext/hash_map,
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ac_cv_cxx_ext_hash_map,
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[AC_LANG_SAVE
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AC_LANG_CPLUSPLUS
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ac_save_CXXFLAGS="$CXXFLAGS"
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CXXFLAGS="$CXXFLAGS -Werror"
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AC_TRY_COMPILE([#include <ext/hash_map>], [using __gnu_cxx::hash_map;],
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ac_cv_cxx_ext_hash_map=yes, ac_cv_cxx_ext_hash_map=no)
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||
CXXFLAGS="$ac_save_CXXFLAGS"
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||
AC_LANG_RESTORE
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||
])
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||
if test "$ac_cv_cxx_ext_hash_map" = yes; then
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AC_DEFINE(HAVE_EXT_HASH_MAP,,[Define if ext/hash_map is present. ])
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fi
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])
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</pre><pre class="programlisting">
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# AC_HEADER_EXT_HASH_SET
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AC_DEFUN([AC_HEADER_EXT_HASH_SET], [
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AC_CACHE_CHECK(for ext/hash_set,
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ac_cv_cxx_ext_hash_set,
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[AC_LANG_SAVE
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AC_LANG_CPLUSPLUS
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ac_save_CXXFLAGS="$CXXFLAGS"
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CXXFLAGS="$CXXFLAGS -Werror"
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AC_TRY_COMPILE([#include <ext/hash_set>], [using __gnu_cxx::hash_set;],
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ac_cv_cxx_ext_hash_set=yes, ac_cv_cxx_ext_hash_set=no)
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CXXFLAGS="$ac_save_CXXFLAGS"
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AC_LANG_RESTORE
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])
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||
if test "$ac_cv_cxx_ext_hash_set" = yes; then
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AC_DEFINE(HAVE_EXT_HASH_SET,,[Define if ext/hash_set is present. ])
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fi
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])
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</pre></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="backwards.third.nocreate_noreplace"></a>No <code class="code">ios::nocreate/ios::noreplace</code>.
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</h4></div></div></div><p>Historically these flags were used with iostreams to control whether
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new files are created or not when opening a file stream, similar to the
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<code class="code">O_CREAT</code> and <code class="code">O_EXCL</code> flags for the
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<code class="function">open(2)</code> system call. Because iostream modes correspond
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to <code class="function">fopen(3)</code> modes these flags are not supported.
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For input streams a new file will not be created anyway, so
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<code class="code">ios::nocreate</code> is not needed.
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For output streams, a new file will be created if it does not exist, which is
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||
consistent with the behaviour of <code class="function">fopen</code>.
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</p><p>When one of these flags is needed a possible alternative is to attempt
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to open the file using <span class="type">std::ifstream</span> first to determine whether
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the file already exists or not. This may not be reliable however, because
|
||
whether the file exists or not could change between opening the
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<span class="type">std::istream</span> and re-opening with an output stream. If you need
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to check for existence and open a file as a single operation then you will
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||
need to use OS-specific facilities outside the C++ standard library, such
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as <code class="function">open(2)</code>.
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</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="backwards.third.streamattach"></a>
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No <code class="code">stream::attach(int fd)</code>
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||
</h4></div></div></div><p>
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Phil Edwards writes: It was considered and rejected for the ISO
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standard. Not all environments use file descriptors. Of those
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that do, not all of them use integers to represent them.
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||
</p><p>
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For a portable solution (among systems which use
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file descriptors), you need to implement a subclass of
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<code class="code">std::streambuf</code> (or
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<code class="code">std::basic_streambuf<..></code>) which opens a file
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given a descriptor, and then pass an instance of this to the
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stream-constructor.
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</p><p>
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An extension is available that implements this.
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<code class="filename"><ext/stdio_filebuf.h></code>
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||
contains a derived class called
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<code class="classname">__gnu_cxx::stdio_filebuf</code>.
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||
This class can be constructed from a C <code class="code">FILE*</code> or a file
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descriptor, and provides the <code class="code">fd()</code> function.
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</p><p>
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For another example of this, refer to
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||
<a class="link" href="http://www.josuttis.com/cppcode/fdstream.html" target="_top">fdstream example</a>
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||
by Nicolai Josuttis.
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</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="backwards.third.support_cxx98"></a>
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Support for C++98 dialect.
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||
</h4></div></div></div><p>Check for complete library coverage of the C++1998/2003 standard.
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</p><pre class="programlisting">
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# AC_HEADER_STDCXX_98
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AC_DEFUN([AC_HEADER_STDCXX_98], [
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AC_CACHE_CHECK(for ISO C++ 98 include files,
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ac_cv_cxx_stdcxx_98,
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||
[AC_LANG_SAVE
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||
AC_LANG_CPLUSPLUS
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||
AC_TRY_COMPILE([
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||
#include <cassert>
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||
#include <cctype>
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||
#include <cerrno>
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||
#include <cfloat>
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||
#include <ciso646>
|
||
#include <climits>
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||
#include <clocale>
|
||
#include <cmath>
|
||
#include <csetjmp>
|
||
#include <csignal>
|
||
#include <cstdarg>
|
||
#include <cstddef>
|
||
#include <cstdio>
|
||
#include <cstdlib>
|
||
#include <cstring>
|
||
#include <ctime>
|
||
|
||
#include <algorithm>
|
||
#include <bitset>
|
||
#include <complex>
|
||
#include <deque>
|
||
#include <exception>
|
||
#include <fstream>
|
||
#include <functional>
|
||
#include <iomanip>
|
||
#include <ios>
|
||
#include <iosfwd>
|
||
#include <iostream>
|
||
#include <istream>
|
||
#include <iterator>
|
||
#include <limits>
|
||
#include <list>
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||
#include <locale>
|
||
#include <map>
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||
#include <memory>
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||
#include <new>
|
||
#include <numeric>
|
||
#include <ostream>
|
||
#include <queue>
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||
#include <set>
|
||
#include <sstream>
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||
#include <stack>
|
||
#include <stdexcept>
|
||
#include <streambuf>
|
||
#include <string>
|
||
#include <typeinfo>
|
||
#include <utility>
|
||
#include <valarray>
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||
#include <vector>
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],,
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ac_cv_cxx_stdcxx_98=yes, ac_cv_cxx_stdcxx_98=no)
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AC_LANG_RESTORE
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||
])
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||
if test "$ac_cv_cxx_stdcxx_98" = yes; then
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AC_DEFINE(STDCXX_98_HEADERS,,[Define if ISO C++ 1998 header files are present. ])
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fi
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||
])
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||
</pre></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="backwards.third.support_tr1"></a>
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Support for C++TR1 dialect.
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</h4></div></div></div><p>Check for library coverage of the TR1 standard.
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</p><pre class="programlisting">
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||
# AC_HEADER_STDCXX_TR1
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AC_DEFUN([AC_HEADER_STDCXX_TR1], [
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AC_CACHE_CHECK(for ISO C++ TR1 include files,
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ac_cv_cxx_stdcxx_tr1,
|
||
[AC_LANG_SAVE
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||
AC_LANG_CPLUSPLUS
|
||
AC_TRY_COMPILE([
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#include <tr1/array>
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||
#include <tr1/ccomplex>
|
||
#include <tr1/cctype>
|
||
#include <tr1/cfenv>
|
||
#include <tr1/cfloat>
|
||
#include <tr1/cinttypes>
|
||
#include <tr1/climits>
|
||
#include <tr1/cmath>
|
||
#include <tr1/complex>
|
||
#include <tr1/cstdarg>
|
||
#include <tr1/cstdbool>
|
||
#include <tr1/cstdint>
|
||
#include <tr1/cstdio>
|
||
#include <tr1/cstdlib>
|
||
#include <tr1/ctgmath>
|
||
#include <tr1/ctime>
|
||
#include <tr1/cwchar>
|
||
#include <tr1/cwctype>
|
||
#include <tr1/functional>
|
||
#include <tr1/memory>
|
||
#include <tr1/random>
|
||
#include <tr1/regex>
|
||
#include <tr1/tuple>
|
||
#include <tr1/type_traits>
|
||
#include <tr1/unordered_set>
|
||
#include <tr1/unordered_map>
|
||
#include <tr1/utility>
|
||
],,
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||
ac_cv_cxx_stdcxx_tr1=yes, ac_cv_cxx_stdcxx_tr1=no)
|
||
AC_LANG_RESTORE
|
||
])
|
||
if test "$ac_cv_cxx_stdcxx_tr1" = yes; then
|
||
AC_DEFINE(STDCXX_TR1_HEADERS,,[Define if ISO C++ TR1 header files are present. ])
|
||
fi
|
||
])
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||
</pre><p>An alternative is to check just for specific TR1 includes, such as <unordered_map> and <unordered_set>.
|
||
</p><pre class="programlisting">
|
||
# AC_HEADER_TR1_UNORDERED_MAP
|
||
AC_DEFUN([AC_HEADER_TR1_UNORDERED_MAP], [
|
||
AC_CACHE_CHECK(for tr1/unordered_map,
|
||
ac_cv_cxx_tr1_unordered_map,
|
||
[AC_LANG_SAVE
|
||
AC_LANG_CPLUSPLUS
|
||
AC_TRY_COMPILE([#include <tr1/unordered_map>], [using std::tr1::unordered_map;],
|
||
ac_cv_cxx_tr1_unordered_map=yes, ac_cv_cxx_tr1_unordered_map=no)
|
||
AC_LANG_RESTORE
|
||
])
|
||
if test "$ac_cv_cxx_tr1_unordered_map" = yes; then
|
||
AC_DEFINE(HAVE_TR1_UNORDERED_MAP,,[Define if tr1/unordered_map is present. ])
|
||
fi
|
||
])
|
||
</pre><pre class="programlisting">
|
||
# AC_HEADER_TR1_UNORDERED_SET
|
||
AC_DEFUN([AC_HEADER_TR1_UNORDERED_SET], [
|
||
AC_CACHE_CHECK(for tr1/unordered_set,
|
||
ac_cv_cxx_tr1_unordered_set,
|
||
[AC_LANG_SAVE
|
||
AC_LANG_CPLUSPLUS
|
||
AC_TRY_COMPILE([#include <tr1/unordered_set>], [using std::tr1::unordered_set;],
|
||
ac_cv_cxx_tr1_unordered_set=yes, ac_cv_cxx_tr1_unordered_set=no)
|
||
AC_LANG_RESTORE
|
||
])
|
||
if test "$ac_cv_cxx_tr1_unordered_set" = yes; then
|
||
AC_DEFINE(HAVE_TR1_UNORDERED_SET,,[Define if tr1/unordered_set is present. ])
|
||
fi
|
||
])
|
||
</pre></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="backwards.third.support_cxx11"></a>
|
||
Support for C++11 dialect.
|
||
</h4></div></div></div><p>Check for baseline language coverage in the compiler for the C++11 standard.
|
||
</p><pre class="programlisting">
|
||
# AC_COMPILE_STDCXX_11
|
||
AC_DEFUN([AC_COMPILE_STDCXX_11], [
|
||
AC_CACHE_CHECK(if g++ supports C++11 features without additional flags,
|
||
ac_cv_cxx_compile_cxx11_native,
|
||
[AC_LANG_SAVE
|
||
AC_LANG_CPLUSPLUS
|
||
AC_TRY_COMPILE([
|
||
template <typename T>
|
||
struct check final
|
||
{
|
||
static constexpr T value{ __cplusplus };
|
||
};
|
||
|
||
typedef check<check<bool>> right_angle_brackets;
|
||
|
||
int a;
|
||
decltype(a) b;
|
||
|
||
typedef check<int> check_type;
|
||
check_type c{};
|
||
check_type&& cr = static_cast<check_type&&>(c);
|
||
|
||
static_assert(check_type::value == 201103L, "C++11 compiler");],,
|
||
ac_cv_cxx_compile_cxx11_native=yes, ac_cv_cxx_compile_cxx11_native=no)
|
||
AC_LANG_RESTORE
|
||
])
|
||
|
||
AC_CACHE_CHECK(if g++ supports C++11 features with -std=c++11,
|
||
ac_cv_cxx_compile_cxx11_cxx,
|
||
[AC_LANG_SAVE
|
||
AC_LANG_CPLUSPLUS
|
||
ac_save_CXXFLAGS="$CXXFLAGS"
|
||
CXXFLAGS="$CXXFLAGS -std=c++11"
|
||
AC_TRY_COMPILE([
|
||
template <typename T>
|
||
struct check final
|
||
{
|
||
static constexpr T value{ __cplusplus };
|
||
};
|
||
|
||
typedef check<check<bool>> right_angle_brackets;
|
||
|
||
int a;
|
||
decltype(a) b;
|
||
|
||
typedef check<int> check_type;
|
||
check_type c{};
|
||
check_type&& cr = static_cast<check_type&&>(c);
|
||
|
||
static_assert(check_type::value == 201103L, "C++11 compiler");],,
|
||
ac_cv_cxx_compile_cxx11_cxx=yes, ac_cv_cxx_compile_cxx11_cxx=no)
|
||
CXXFLAGS="$ac_save_CXXFLAGS"
|
||
AC_LANG_RESTORE
|
||
])
|
||
|
||
AC_CACHE_CHECK(if g++ supports C++11 features with -std=gnu++11,
|
||
ac_cv_cxx_compile_cxx11_gxx,
|
||
[AC_LANG_SAVE
|
||
AC_LANG_CPLUSPLUS
|
||
ac_save_CXXFLAGS="$CXXFLAGS"
|
||
CXXFLAGS="$CXXFLAGS -std=gnu++11"
|
||
AC_TRY_COMPILE([
|
||
template <typename T>
|
||
struct check final
|
||
{
|
||
static constexpr T value{ __cplusplus };
|
||
};
|
||
|
||
typedef check<check<bool>> right_angle_brackets;
|
||
|
||
int a;
|
||
decltype(a) b;
|
||
|
||
typedef check<int> check_type;
|
||
check_type c{};
|
||
check_type&& cr = static_cast<check_type&&>(c);
|
||
|
||
static_assert(check_type::value == 201103L, "C++11 compiler");],,
|
||
ac_cv_cxx_compile_cxx11_gxx=yes, ac_cv_cxx_compile_cxx11_gxx=no)
|
||
CXXFLAGS="$ac_save_CXXFLAGS"
|
||
AC_LANG_RESTORE
|
||
])
|
||
|
||
if test "$ac_cv_cxx_compile_cxx11_native" = yes ||
|
||
test "$ac_cv_cxx_compile_cxx11_cxx" = yes ||
|
||
test "$ac_cv_cxx_compile_cxx11_gxx" = yes; then
|
||
AC_DEFINE(HAVE_STDCXX_11,,[Define if g++ supports C++11 features. ])
|
||
fi
|
||
])
|
||
</pre><p>Check for library coverage of the C++2011 standard.
|
||
(Some library headers are commented out in this check, they are
|
||
not currently provided by libstdc++).
|
||
</p><pre class="programlisting">
|
||
# AC_HEADER_STDCXX_11
|
||
AC_DEFUN([AC_HEADER_STDCXX_11], [
|
||
AC_CACHE_CHECK(for ISO C++11 include files,
|
||
ac_cv_cxx_stdcxx_11,
|
||
[AC_REQUIRE([AC_COMPILE_STDCXX_11])
|
||
AC_LANG_SAVE
|
||
AC_LANG_CPLUSPLUS
|
||
ac_save_CXXFLAGS="$CXXFLAGS"
|
||
CXXFLAGS="$CXXFLAGS -std=gnu++11"
|
||
|
||
AC_TRY_COMPILE([
|
||
#include <cassert>
|
||
#include <ccomplex>
|
||
#include <cctype>
|
||
#include <cerrno>
|
||
#include <cfenv>
|
||
#include <cfloat>
|
||
#include <cinttypes>
|
||
#include <ciso646>
|
||
#include <climits>
|
||
#include <clocale>
|
||
#include <cmath>
|
||
#include <csetjmp>
|
||
#include <csignal>
|
||
#include <cstdalign>
|
||
#include <cstdarg>
|
||
#include <cstdbool>
|
||
#include <cstddef>
|
||
#include <cstdint>
|
||
#include <cstdio>
|
||
#include <cstdlib>
|
||
#include <cstring>
|
||
#include <ctgmath>
|
||
#include <ctime>
|
||
// #include <cuchar>
|
||
#include <cwchar>
|
||
#include <cwctype>
|
||
|
||
#include <algorithm>
|
||
#include <array>
|
||
#include <atomic>
|
||
#include <bitset>
|
||
#include <chrono>
|
||
// #include <codecvt>
|
||
#include <complex>
|
||
#include <condition_variable>
|
||
#include <deque>
|
||
#include <exception>
|
||
#include <forward_list>
|
||
#include <fstream>
|
||
#include <functional>
|
||
#include <future>
|
||
#include <initializer_list>
|
||
#include <iomanip>
|
||
#include <ios>
|
||
#include <iosfwd>
|
||
#include <iostream>
|
||
#include <istream>
|
||
#include <iterator>
|
||
#include <limits>
|
||
#include <list>
|
||
#include <locale>
|
||
#include <map>
|
||
#include <memory>
|
||
#include <mutex>
|
||
#include <new>
|
||
#include <numeric>
|
||
#include <ostream>
|
||
#include <queue>
|
||
#include <random>
|
||
#include <ratio>
|
||
#include <regex>
|
||
#include <scoped_allocator>
|
||
#include <set>
|
||
#include <sstream>
|
||
#include <stack>
|
||
#include <stdexcept>
|
||
#include <streambuf>
|
||
#include <string>
|
||
#include <system_error>
|
||
#include <thread>
|
||
#include <tuple>
|
||
#include <typeindex>
|
||
#include <typeinfo>
|
||
#include <type_traits>
|
||
#include <unordered_map>
|
||
#include <unordered_set>
|
||
#include <utility>
|
||
#include <valarray>
|
||
#include <vector>
|
||
],,
|
||
ac_cv_cxx_stdcxx_11=yes, ac_cv_cxx_stdcxx_11=no)
|
||
AC_LANG_RESTORE
|
||
CXXFLAGS="$ac_save_CXXFLAGS"
|
||
])
|
||
if test "$ac_cv_cxx_stdcxx_11" = yes; then
|
||
AC_DEFINE(STDCXX_11_HEADERS,,[Define if ISO C++11 header files are present. ])
|
||
fi
|
||
])
|
||
</pre><p>As is the case for TR1 support, these autoconf macros can be made for a finer-grained, per-header-file check. For
|
||
<code class="filename"><unordered_map></code>
|
||
</p><pre class="programlisting">
|
||
# AC_HEADER_UNORDERED_MAP
|
||
AC_DEFUN([AC_HEADER_UNORDERED_MAP], [
|
||
AC_CACHE_CHECK(for unordered_map,
|
||
ac_cv_cxx_unordered_map,
|
||
[AC_REQUIRE([AC_COMPILE_STDCXX_11])
|
||
AC_LANG_SAVE
|
||
AC_LANG_CPLUSPLUS
|
||
ac_save_CXXFLAGS="$CXXFLAGS"
|
||
CXXFLAGS="$CXXFLAGS -std=gnu++11"
|
||
AC_TRY_COMPILE([#include <unordered_map>], [using std::unordered_map;],
|
||
ac_cv_cxx_unordered_map=yes, ac_cv_cxx_unordered_map=no)
|
||
CXXFLAGS="$ac_save_CXXFLAGS"
|
||
AC_LANG_RESTORE
|
||
])
|
||
if test "$ac_cv_cxx_unordered_map" = yes; then
|
||
AC_DEFINE(HAVE_UNORDERED_MAP,,[Define if unordered_map is present. ])
|
||
fi
|
||
])
|
||
</pre><pre class="programlisting">
|
||
# AC_HEADER_UNORDERED_SET
|
||
AC_DEFUN([AC_HEADER_UNORDERED_SET], [
|
||
AC_CACHE_CHECK(for unordered_set,
|
||
ac_cv_cxx_unordered_set,
|
||
[AC_REQUIRE([AC_COMPILE_STDCXX_11])
|
||
AC_LANG_SAVE
|
||
AC_LANG_CPLUSPLUS
|
||
ac_save_CXXFLAGS="$CXXFLAGS"
|
||
CXXFLAGS="$CXXFLAGS -std=gnu++11"
|
||
AC_TRY_COMPILE([#include <unordered_set>], [using std::unordered_set;],
|
||
ac_cv_cxx_unordered_set=yes, ac_cv_cxx_unordered_set=no)
|
||
CXXFLAGS="$ac_save_CXXFLAGS"
|
||
AC_LANG_RESTORE
|
||
])
|
||
if test "$ac_cv_cxx_unordered_set" = yes; then
|
||
AC_DEFINE(HAVE_UNORDERED_SET,,[Define if unordered_set is present. ])
|
||
fi
|
||
])
|
||
</pre><p>
|
||
Some C++11 features first appeared in GCC 4.3 and could be enabled by
|
||
<code class="option">-std=c++0x</code> and <code class="option">-std=gnu++0x</code> for GCC
|
||
releases which pre-date the 2011 standard. Those C++11 features and GCC's
|
||
support for them were still changing until the 2011 standard was finished,
|
||
but the autoconf checks above could be extended to test for incomplete
|
||
C++11 support with <code class="option">-std=c++0x</code> and
|
||
<code class="option">-std=gnu++0x</code>.
|
||
</p></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="backwards.third.iterator_type"></a>
|
||
<code class="code">Container::iterator_type</code> is not necessarily <code class="code">Container::value_type*</code>
|
||
</h4></div></div></div><p>
|
||
This is a change in behavior from older versions. Now, most
|
||
<span class="type">iterator_type</span> typedefs in container classes are POD
|
||
objects, not <span class="type">value_type</span> pointers.
|
||
</p></div></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="api.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="appendix_porting.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="appendix_free.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">API Evolution and Deprecation History </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Appendix C.
|
||
Free Software Needs Free Documentation
|
||
|
||
</td></tr></table></div></body></html> |