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2002-10-07 Jonathan Wakely <jw@kayari.org> * docs/html/configopts.html, docs/html/documentation.html, docs/html/explanations.html, docs/html/install.html, docs/html/17_intro/contribute.html, docs/html/17_intro/howto.html, docs/html/17_intro/license.html, docs/html/18_support/howto.html, docs/html/19_diagnostics/howto.html, docs/html/20_util/howto.html, docs/html/21_strings/howto.html, docs/html/22_locale/codecvt.html, docs/html/22_locale/ctype.html, docs/html/22_locale/howto.html, docs/html/22_locale/locale.html, docs/html/22_locale/messages.html, docs/html/23_containers/howto.html, docs/html/24_iterators/howto.html, docs/html/25_algorithms/howto.html, docs/html/26_numerics/howto.html, docs/html/27_io/howto.html, docs/html/ext/howto.html, docs/html/ext/sgiexts.html, docs/html/faq/index.html: Add DOCTYPEs. From-SVN: r57903
639 lines
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HTML
639 lines
27 KiB
HTML
<?xml version="1.0" encoding="ISO-8859-1"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
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<meta name="AUTHOR" content="pme@gcc.gnu.org (Phil Edwards)" />
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<meta name="KEYWORDS" content="HOWTO, libstdc++, GCC, g++, libg++, STL" />
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<meta name="DESCRIPTION" content="Notes for the libstdc++ extensions." />
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<meta name="GENERATOR" content="vi and eight fingers" />
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<title>libstdc++-v3 HOWTO: Extensions</title>
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<link rel="StyleSheet" href="../lib3styles.css" />
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</head>
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<body>
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<h1 class="centered"><a name="top">Extensions</a></h1>
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<p>Here we will make an attempt at describing the non-Standard extensions to
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the library. Some of these are from SGI's STL, some of these are GNU's,
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and some just seemed to appear on the doorstep.
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</p>
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<p><strong>Before you leap in and use these</strong>, be aware of two things:
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</p>
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<ol>
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<li>Non-Standard means exactly that. The behavior, and the very
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existence, of these extensions may change with little or no
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warning. (Ideally, the really good ones will appear in the next
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revision of C++.) Also, other platforms, other compilers, other
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versions of g++ or libstdc++-v3 may not recognize these names, or
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treat them differently, or... </li>
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<li>You should know how to <a href="../faq/index.html#5_4">access
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these headers properly</a>. </li>
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</ol>
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<!-- ####################################################### -->
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<hr />
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<h1>Contents</h1>
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<ul>
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<li><a href="#1">Ropes and trees and hashes, oh my!</a></li>
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<li><a href="#2">Added members and types</a></li>
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<li><a href="#3">Allocators (versions 3.0, 3.1, 3.2)</a></li>
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<li><a href="#6">Allocators (version 3.3)</a></li>
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<li><a href="#4">Compile-time checks</a></li>
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<li><a href="#5">LWG Issues</a></li>
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</ul>
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<hr />
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<!-- ####################################################### -->
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<h2><a name="1">Ropes and trees and hashes, oh my!</a></h2>
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<p>The SGI headers</p>
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<pre>
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<bvector>
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<hash_map>
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<hash_set>
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<rope>
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<slist>
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<tree>
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</pre>
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<p>are all here; <code><bvector></code> exposes the old bit_vector
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class that was used before specialization of vector<bool> was
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available (it's actually a typedef for the specialization now).
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<code><hash_map></code> and <code><hash_set></code>
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are discussed further below. <code><rope></code> is the SGI
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specialization for large strings ("rope," "large
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strings," get it? love those SGI folks).
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<code><slist></code> is a singly-linked list, for when the
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doubly-linked <code>list<></code> is too much space overhead, and
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<code><tree></code> exposes the red-black tree classes used in the
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implementation of the standard maps and sets.
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</p>
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<p>Okay, about those hashing classes... I'm going to foist most of the
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work off onto SGI's own site.
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</p>
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<p>Each of the associative containers map, multimap, set, and multiset
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have a counterpart which uses a
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<a href="http://www.sgi.com/Technology/STL/HashFunction.html">hashing
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function</a> to do the arranging, instead of a strict weak ordering
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function. The classes take as one of their template parameters a
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function object that will return the hash value; by default, an
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instantiation of
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<a href="http://www.sgi.com/Technology/STL/hash.html">hash</a>.
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You should specialize this functor for your class, or define your own,
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before trying to use one of the hashing classes.
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</p>
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<p>The hashing classes support all the usual associative container
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functions, as well as some extra constructors specifying the number
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of buckets, etc.
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</p>
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<p>Why would you want to use a hashing class instead of the
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"normal" implementations? Matt Austern writes:
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</p>
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<blockquote><em>[W]ith a well chosen hash function, hash tables
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generally provide much better average-case performance than binary
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search trees, and much worse worst-case performance. So if your
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implementation has hash_map, if you don't mind using nonstandard
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components, and if you aren't scared about the possibility of
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pathological cases, you'll probably get better performance from
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hash_map.</em></blockquote>
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<p>(Side note: for those of you wondering, <strong>"Why wasn't a hash
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table included in the Standard in the first #!$@ place?"</strong>
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I'll give a quick answer: it was proposed, but too late and in too
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unorganized a fashion. Some sort of hashing will undoubtedly be
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included in a future Standard.)
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</p>
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<p>Return <a href="#top">to top of page</a> or
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<a href="../faq/index.html">to the FAQ</a>.
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</p>
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<hr />
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<h2><a name="2">Added members and types</a></h2>
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<p>Some of the classes in the Standard Library have additional
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publicly-available members, and some classes are themselves not in
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the standard. Of those, some are intended purely for the implementors,
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for example, additional typedefs. Those won't be described here
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(or anywhere else).
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</p>
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<ul>
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<li>The extensions added by SGI are so numerous that they have
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<a href="sgiexts.html">their own page</a>. Since the SGI STL is no
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longer actively maintained, we will try and keep this code working
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ourselves.</li>
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<li>3.0.x <code>filebuf</code>s have another ctor with this signature:
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<br />
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<code>basic_filebuf(__c_file_type*, ios_base::openmode, int_type);</code>
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<br />This comes in very handy in a number of places, such as
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attaching Unix sockets, pipes, and anything else which uses file
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descriptors, into the IOStream buffering classes. The three
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arguments are as follows:
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<ul>
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<li><code>__c_file_type* F </code>
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// the __c_file_type typedef usually boils down to stdio's FILE
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</li>
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<li><code>ios_base::openmode M </code>
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// same as all the other uses of openmode
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</li>
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<li><code>int_type B </code>
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// buffer size, defaults to BUFSIZ if not specified
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</li>
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</ul>
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For those wanting to use file descriptors instead of FILE*'s, I
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invite you to contemplate the mysteries of C's <code>fdopen()</code>.
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</li>
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<li>In library snapshot 3.0.95 and later, <code>filebuf</code>s bring
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back an old extension: the <code>fd()</code> member function. The
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integer returned from this function can be used for whatever file
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descriptors can be used for on your platform. Naturally, the
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library cannot track what you do on your own with a file descriptor,
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so if you perform any I/O directly, don't expect the library to be
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aware of it.
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</li>
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<li>Beginning with 3.1, the extra <code>filebuf</code> constructor and
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the <code>fd()</code> function were removed from the standard
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filebuf. Instead, <code><ext/stdio_filebuf.h></code> contains
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a derived class called <code>__gnu_cxx::stdio_filebuf</code>.
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</li>
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</ul>
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<p>Return <a href="#top">to top of page</a> or
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<a href="../faq/index.html">to the FAQ</a>.
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</p>
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<hr />
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<h2><a name="3">Allocators (versions 3.0, 3.1, 3.2)</a></h2>
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<p>Thread-safety, space efficiency, high speed, portability... this is a
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mess. Where to begin?
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</p>
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<h3>The Rules</h3>
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<p>The C++ standard only gives a few directives in this area:
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</p>
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<ul>
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<li>When you add elements to a container, and the container must allocate
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more memory to hold them, the container makes the request via its
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<code>Allocator</code> template parameter. This includes adding
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char's to the string class, which acts as a regular STL container
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in this respect.
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</li>
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<li>The default <code>Allocator</code> of every container-of-T is
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<code>std::allocator<T></code>.
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</li>
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<li>The interface of the <code>allocator<T></code> class is
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extremely simple. It has about 20 public declarations (nested
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typedefs, member functions, etc), but the two which concern us most
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are:
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<pre>
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T* allocate (size_type n, const void* hint = 0);
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void deallocate (T* p, size_type n);</pre>
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(This is a simplicifcation; the real signatures use nested typedefs.)
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The <code>"n"</code> arguments in both those functions is a
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<em>count</em> of the number of T's to allocate space for,
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<em>not their total size</em>.
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</li>
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<li>"The storage is obtained by calling
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<code>::operator new(size_t)</code>, but it is unspecified when or
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how often this function is called. The use of <code>hint</code>
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is unspecified, but intended as an aid to locality if an
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implementation so desires." [20.4.1.1]/6
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</li>
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</ul>
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<h3>Problems and Possibilities</h3>
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<p>The easiest way of fulfilling the requirements is to call operator new
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each time a container needs memory, and to call operator delete each
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time the container releases memory. <strong>BUT</strong>
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<a href="http://gcc.gnu.org/ml/libstdc++/2001-05/msg00105.html">this
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method is horribly slow</a>.
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</p>
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<p>Or we can keep old memory around, and reuse it in a pool to save time.
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The old libstdc++-v2 used a memory pool, and so do we. As of 3.0,
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<a href="http://gcc.gnu.org/ml/libstdc++/2001-05/msg00136.html">it's
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on by default</a>. The pool is shared among all the containers in the
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program: when your program's std::vector<int> gets cut in half
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and frees a bunch of its storage, that memory can be reused by the
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private std::list<WonkyWidget> brought in from a KDE library
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that you linked against. And we don't have to call operators new and
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delete to pass the memory on, either, which is a speed bonus.
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<strong>BUT</strong>...
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</p>
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<p>What about threads? No problem: in a threadsafe environment, the
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memory pool is manipulated atomically, so you can grow a container in
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one thread and shrink it in another, etc. <strong>BUT</strong> what
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if threads in libstdc++-v3 aren't set up properly?
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<a href="../faq/index.html#5_6">That's been answered already</a>.
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</p>
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<p><strong>BUT</strong> what if you want to use your own allocator? What
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if you plan on using a runtime-loadable version of malloc() which uses
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shared telepathic anonymous mmap'd sections serializable over a
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network, so that memory requests <em>should</em> go through malloc?
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And what if you need to debug it?
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</p>
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<p>Well then:
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</p>
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<h3>Available allocators in namespace std</h3>
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<p>First I'll describe the situation as it exists for the code which
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was released in GCC 3.1 and 3.2. Then I'll describe the differences
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for 3.0. The allocator classes also have source documentation,
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which is described <a href="../documentation.html#4">here</a> (you
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will need to retrieve the maintainer-level docs, as almost none of
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these entities are in the ISO standard).
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</p>
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<p>As a general rule of thumb, users are not allowed to use names which
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begin with an underscore. This means that to be portable between
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compilers, none of the following may be used in your program directly.
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(If you decide to be unportable, then you're free do do what you want,
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but it's not our fault if stuff breaks.) They are presented here for
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information for maintainers and contributors in addition to users.
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</p>
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<p>These classes are always available:
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</p>
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<ul>
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<li><code>__new_alloc</code> simply wraps <code>::operator new</code>
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and <code>::operator delete</code>.
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</li>
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<li><code>__malloc_alloc_template<int inst></code> simply wraps
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<code>malloc</code> and <code>free</code>. There is also a hook
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for an out-of-memory handler (for new/delete this is taken care of
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elsewhere). The <code>inst</code> parameter is described below.
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This class was called <code>malloc_alloc</code> in earlier versions.
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</li>
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<li><code>allocator<T></code> has already been described; it is
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The Standard Allocator for instances of T. It uses the internal
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<code>__alloc</code> typedef (see below) to satisy its requests.
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</li>
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<li><code>__simple_alloc<T,A></code> is a wrapper around another
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allocator, A, which itself is an allocator for instances of T.
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This is primarily used in an internal "allocator traits"
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class which helps encapsulate the different styles of allocators.
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</li>
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<li><code>__debug_alloc<A></code> is also a wrapper around an
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arbitrary allocator A. It passes on slightly increased size
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requests to A, and uses the extra memory to store size information.
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When a pointer is passed to <code>deallocate()</code>, the stored
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size is checked, and assert() is used to guarantee they match.
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</li>
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<li><code>__allocator<T,A></code> is an adaptor. Many of these
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allocator classes have a consistent yet non-standard interface.
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Such classes can be changed to a conforming interface with this
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wrapper: <code>__allocator<T, __alloc></code> is thus the
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same as <code>allocator<T></code>.
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</li>
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</ul>
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<p>An internal typedef, <code> __mem_interface </code>, is defined to be
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<code>__new_alloc</code> by default.
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</p>
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<p>Normally,
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<code> __default_alloc_template<bool thr, int inst> </code>
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is also available. This is the high-speed pool, called the default
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node allocator. The reusable memory is shared among identical
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instantiations of
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this type. It calls through <code>__mem_interface</code> to obtain
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new memory when its lists run out. If a client container requests a
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block larger than a certain threshold size, then the pool is bypassed,
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and the allocate/deallocate request is passed to
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<code>__mem_interface</code> directly.
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</p>
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<p>Its <code>inst</code> parameter is described below. The
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<code>thr</code> boolean determines whether the pool should be
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manipulated atomically or not. Two typedefs are provided:
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<code>__alloc</code> is defined as this node allocator with thr=true,
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and therefore is threadsafe, while <code>__single_client_alloc</code>
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defines thr=false, and is slightly faster but unsafe for multiple
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threads.
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</p>
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<p>(Note that the GCC thread abstraction layer allows us to provide safe
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zero-overhead stubs for the threading routines, if threads were
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disabled at configuration time. In this situation,
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<code>__alloc</code> should not be noticably slower than
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<code>__single_client_alloc</code>.)
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</p>
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<p>[Another threadsafe allocator where each thread keeps its own free
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list, so that no locking is needed, might be described here.]
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</p>
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<h3>A cannon to swat a fly:<code> __USE_MALLOC</code></h3>
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<p>If you've already read <a href="../23_containers/howto.html#3">this
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advice</a> and decided to define this macro, then the situation changes
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thusly:
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</p>
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<ol>
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<li><code>__mem_interface</code>, and</li>
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<li><code>__alloc</code>, and</li>
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<li><code>__single_client_alloc</code> are all typedef'd to
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<code>__malloc_alloc_template</code>.</li>
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<li><code>__default_alloc_template</code> is no longer available.
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At all. Anywhere.</li>
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</ol>
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<h3>Writing your own allocators</h3>
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<p>Depending on your application (a specific program, a generic library,
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etc), allocator classes tend to be one of two styles: "SGI"
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or "standard". See the comments in stl_alloc.h for more
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information on this crucial difference.
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</p>
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<p>At the bottom of that header is a helper type,
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<code>_Alloc_traits</code>, and various specializations of it. This
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allows the container classes to make possible compile-time
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optimizations based on features of the allocator. You should provide
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a specialization of this type for your allocator (doing so takes only
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two or three statements).
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</p>
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<h3>Using non-default allocators</h3>
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<p>You can specify different memory management schemes on a per-container
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basis, by overriding the default <code>Allocator</code> template
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parameter. For example, an easy
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(but nonportable)
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method of specifying that only malloc/free should be used instead of
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the default node allocator is:
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</p>
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<pre>
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std::list <my_type, std::__malloc_alloc_template<0> > my_malloc_based_list;</pre>
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Likewise, a debugging form of whichever allocator is currently in use:
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<pre>
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std::deque <my_type, std::__debug_alloc<std::__alloc> > debug_deque;</pre>
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<h3><code>inst</code></h3>
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<p>The <code>__malloc_alloc_template</code> and
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<code>__default_alloc_template</code> classes take an integer parameter,
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called inst here. This number is completely unused.
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</p>
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<p>The point of the number is to allow multiple instantiations of the
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classes without changing the semantics at all. All three of
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</p>
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<pre>
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typedef __default_alloc_template<true,0> normal;
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typedef __default_alloc_template<true,1> private;
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typedef __default_alloc_template<true,42> also_private;</pre>
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<p>behave exactly the same way. However, the memory pool for each type
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(and remember that different instantiations result in different types)
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remains separate.
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</p>
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<p>The library uses <strong>0</strong> in all its instantiations. If you
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wish to keep separate free lists for a particular purpose, use a
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different number.
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</p>
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<h3>3.0.x</h3>
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<p>For 3.0.x, many of the names were incorrectly <em>not</em> prefixed
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with underscores. So symbols such as "std::single_client_alloc"
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are present. Be very careful to not depend on these names any more
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than you would depend on implementation-only names.
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</p>
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<p>Certain macros like <code>_NOTHREADS</code> and <code>__STL_THREADS</code>
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can affect the 3.0.x allocators. Do not use them. Those macros have
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been completely removed for 3.1.
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</p>
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<p>Return <a href="#top">to top of page</a> or
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<a href="../faq/index.html">to the FAQ</a>.
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</p>
|
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|
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<hr />
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<h2><a name="6">Allocators (version 3.3)</a></h2>
|
|
<p>Changes are coming...
|
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</p>
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<p>Return <a href="#top">to top of page</a> or
|
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<a href="../faq/index.html">to the FAQ</a>.
|
|
</p>
|
|
|
|
<hr />
|
|
<h2><a name="4">Compile-time checks</a></h2>
|
|
<p>Currently libstdc++-v3 uses the concept checkers from the Boost
|
|
library to perform <a href="../19_diagnostics/howto.html#3">optional
|
|
compile-time checking</a> of template instantiations of the standard
|
|
containers. They are described in the linked-to page.
|
|
</p>
|
|
<p>Return <a href="#top">to top of page</a> or
|
|
<a href="../faq/index.html">to the FAQ</a>.
|
|
</p>
|
|
|
|
<hr />
|
|
<h2><a name="5">LWG Issues</a></h2>
|
|
<p>Everybody's got issues. Even the C++ Standard Library.
|
|
</p>
|
|
<p>The Library Working Group, or LWG, is the ISO subcommittee responsible
|
|
for making changes to the library. They periodically publish an
|
|
Issues List containing problems and possible solutions. As they reach
|
|
a consensus on proposed solutions, we often incorporate the solution
|
|
into libstdc++-v3.
|
|
</p>
|
|
<p>Here are the issues which have resulted in code changes to the library.
|
|
The links are to the specific defect reports from a <strong>partial
|
|
copy</strong> of the Issues List. You can read the full version online
|
|
at the <a href="http://www.dkuug.dk/jtc1/sc22/wg21/">ISO C++
|
|
Committee homepage</a>, linked to on the
|
|
<a href="http://gcc.gnu.org/readings.html">GCC "Readings"
|
|
page</a>. If
|
|
you spend a lot of time reading the issues, we recommend downloading
|
|
the ZIP file and reading them locally.
|
|
</p>
|
|
<p>(NB: <strong>partial copy</strong> means that not all links within
|
|
the lwg-*.html pages will work.
|
|
Specifically, links to defect reports that have not been accorded full
|
|
DR status will probably break. Rather than trying to mirror the
|
|
entire issues list on our overworked web server, we recommend you go
|
|
to the LWG homepage instead.)
|
|
</p>
|
|
<p>
|
|
If a DR is not listed here, we may simply not have gotten to it yet;
|
|
feel free to submit a patch. Search the include/bits and src
|
|
directories for appearances of _GLIBCPP_RESOLVE_LIB_DEFECTS for
|
|
examples of style. Note that we usually do not make changes to the code
|
|
until an issue has reached <a href="lwg-active.html#DR">DR</a> status.
|
|
</p>
|
|
<dl>
|
|
<dt><a href="lwg-defects.html#5">5</a>:
|
|
<em>string::compare specification questionable</em>
|
|
</dt>
|
|
<dd>This should be two overloaded functions rather than a single function.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#17">17</a>:
|
|
<em>Bad bool parsing</em>
|
|
</dt>
|
|
<dd>Apparently extracting Boolean values was messed up...
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#22">22</a>:
|
|
<em>Member open vs flags</em>
|
|
</dt>
|
|
<dd>Re-opening a file stream does <em>not</em> clear the state flags.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#25">25</a>:
|
|
<em>String operator<< uses width() value wrong</em>
|
|
</dt>
|
|
<dd>Padding issues.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#48">48</a>:
|
|
<em>Use of non-existent exception constructor</em>
|
|
</dt>
|
|
<dd>An instance of <code>ios_base::failure</code> is constructed instead.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#49">49</a>:
|
|
<em>Underspecification of ios_base::sync_with_stdio</em>
|
|
</dt>
|
|
<dd>The return type is the <em>previous</em> state of synchronization.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#50">50</a>:
|
|
<em>Copy constructor and assignment operator of ios_base</em>
|
|
</dt>
|
|
<dd>These members functions are declared <code>private</code> and are
|
|
thus inaccessible. Specifying the correct semantics of
|
|
"copying stream state" was deemed too complicated.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#68">68</a>:
|
|
<em>Extractors for char* should store null at end</em>
|
|
</dt>
|
|
<dd>And they do now. An editing glitch in the last item in the list of
|
|
[27.6.1.2.3]/7.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#74">74</a>:
|
|
<em>Garbled text for codecvt::do_max_length</em>
|
|
</dt>
|
|
<dd>The text of the standard was gibberish. Typos gone rampant.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#83">83</a>:
|
|
<em>string::npos vs. string::max_size()</em>
|
|
</dt>
|
|
<dd>Safety checks on the size of the string should test against
|
|
<code>max_size()</code> rather than <code>npos</code>.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#109">109</a>:
|
|
<em>Missing binders for non-const sequence elements</em>
|
|
</dt>
|
|
<dd>The <code>binder1st</code> and <code>binder2nd</code> didn't have an
|
|
<code>operator()</code> taking a non-const parameter.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#110">110</a>:
|
|
<em>istreambuf_iterator::equal not const</em>
|
|
</dt>
|
|
<dd>This was not a const member function. Note that the DR says to
|
|
replace the function with a const one; we have instead provided an
|
|
overloaded version with identical contents.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#117">117</a>:
|
|
<em>basic_ostream uses nonexistent num_put member functions</em>
|
|
</dt>
|
|
<dd><code>num_put::put()</code> was overloaded on the wrong types.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#118">118</a>:
|
|
<em>basic_istream uses nonexistent num_get member functions</em>
|
|
</dt>
|
|
<dd>Same as 117, but for <code>num_get::get()</code>.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#129">129</a>:
|
|
<em>Need error indication from seekp() and seekg()</em>
|
|
</dt>
|
|
<dd>These functions set <code>failbit</code> on error now.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#136">136</a>:
|
|
<em>seekp, seekg setting wrong streams?</em>
|
|
</dt>
|
|
<dd><code>seekp</code> should only set the output stream, and
|
|
<code>seekg</code> should only set the input stream.
|
|
</dd>
|
|
|
|
<!--<dt><a href="lwg-defects.html#159">159</a>:
|
|
<em>Strange use of underflow()</em>
|
|
</dt>
|
|
<dd>In fstream.tcc, the basic_filebuf<>::showmanyc() function
|
|
should probably not be calling <code>underflow()</code>.
|
|
</dd> -->
|
|
|
|
<dt><a href="lwg-active.html#167">167</a>:
|
|
<em>Improper use of traits_type::length()</em>
|
|
</dt>
|
|
<dd><code>op<<</code> with a <code>const char*</code> was
|
|
calculating an incorrect number of characters to write.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#181">181</a>:
|
|
<em>make_pair() unintended behavior</em>
|
|
</dt>
|
|
<dd>This function used to take its arguments as reference-to-const, now
|
|
it copies them (pass by value).
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#195">195</a>:
|
|
<em>Should basic_istream::sentry's constructor ever set eofbit?</em>
|
|
</dt>
|
|
<dd>Yes, it can, specifically if EOF is reached while skipping whitespace.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#211">211</a>:
|
|
<em>operator>>(istream&, string&) doesn't set failbit</em>
|
|
</dt>
|
|
<dd>If nothing is extracted into the string, <code>op>></code> now
|
|
sets <code>failbit</code> (which can cause an exception, etc, etc).
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#214">214</a>:
|
|
<em>set::find() missing const overload</em>
|
|
</dt>
|
|
<dd>Both <code>set</code> and <code>multiset</code> were missing
|
|
overloaded find, lower_bound, upper_bound, and equal_range functions
|
|
for const instances.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#251">251</a>:
|
|
<em>basic_stringbuf missing allocator_type</em>
|
|
</dt>
|
|
<dd>This nested typdef was originally not specified.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#265">265</a>:
|
|
<em>std::pair::pair() effects overly restrictive</em>
|
|
</dt>
|
|
<dd>The default ctor would build its members from copies of temporaries;
|
|
now it simply uses their respective default ctors.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#266">266</a>:
|
|
<em>bad_exception::~bad_exception() missing Effects clause</em>
|
|
</dt>
|
|
<dd>The <code>bad_</code>* classes no longer have destructors (they
|
|
are trivial), since no description of them was ever given.
|
|
</dd>
|
|
|
|
<dt><a href="lwg-defects.html#275">275</a>:
|
|
<em>Wrong type in num_get::get() overloads</em>
|
|
</dt>
|
|
<dd>Similar to 118.
|
|
</dd>
|
|
|
|
<!--
|
|
<dt><a href="lwg-defects.html#"></a>:
|
|
<em></em>
|
|
</dt>
|
|
<dd>
|
|
</dd>
|
|
|
|
-->
|
|
</dl>
|
|
<p>Return <a href="#top">to top of page</a> or
|
|
<a href="../faq/index.html">to the FAQ</a>.
|
|
</p>
|
|
|
|
|
|
<!-- ####################################################### -->
|
|
|
|
<hr />
|
|
<p class="fineprint"><em>
|
|
See <a href="../17_intro/license.html">license.html</a> for copying conditions.
|
|
Comments and suggestions are welcome, and may be sent to
|
|
<a href="mailto:libstdc++@gcc.gnu.org">the libstdc++ mailing list</a>.
|
|
</em></p>
|
|
|
|
|
|
</body>
|
|
</html>
|