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| author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
|---|---|---|
| committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
| commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
| tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libstdc++-v3/doc/html/manual/bk01pt03ch21s03.html | |
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Diffstat (limited to 'libstdc++-v3/doc/html/manual/bk01pt03ch21s03.html')
| -rw-r--r-- | libstdc++-v3/doc/html/manual/bk01pt03ch21s03.html | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/libstdc++-v3/doc/html/manual/bk01pt03ch21s03.html b/libstdc++-v3/doc/html/manual/bk01pt03ch21s03.html new file mode 100644 index 000000000..2f75d608b --- /dev/null +++ b/libstdc++-v3/doc/html/manual/bk01pt03ch21s03.html @@ -0,0 +1,50 @@ +<?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>Deprecated HP/SGI</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.76.1"/><meta name="keywords" content=" ISO C++ , library "/><link rel="home" href="../spine.html" title="The GNU C++ Library"/><link rel="up" href="ext_containers.html" title="Chapter 21. Containers"/><link rel="prev" href="bk01pt03ch21s02.html" title="HP/SGI"/><link rel="next" href="ext_utilities.html" title="Chapter 22. Utilities"/></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Deprecated HP/SGI</th></tr><tr><td align="left"><a accesskey="p" href="bk01pt03ch21s02.html">Prev</a> </td><th width="60%" align="center">Chapter 21. Containers</th><td align="right"> <a accesskey="n" href="ext_utilities.html">Next</a></td></tr></table><hr/></div><div class="section" title="Deprecated HP/SGI"><div class="titlepage"><div><div><h2 class="title"><a id="manual.ext.containers.deprecated_sgi"/>Deprecated HP/SGI</h2></div></div></div><p> + The SGI hashing classes <code class="classname">hash_set</code> and + <code class="classname">hash_set</code> have been deprecated by the + unordered_set, unordered_multiset, unordered_map, + unordered_multimap containers in TR1 and the upcoming C++0x, and + may be removed in future releases. + </p><p>The SGI headers</p><pre class="programlisting"> + <hash_map> + <hash_set> + <rope> + <slist> + <rb_tree> + </pre><p>are all here; + <code class="code"><hash_map></code> and <code class="code"><hash_set></code> + are deprecated but available as backwards-compatible extensions, + as discussed further below. <code class="code"><rope></code> is the + SGI specialization for large strings ("rope," + "large strings," get it? Love that geeky humor.) + <code class="code"><slist></code> is a singly-linked list, for when the + doubly-linked <code class="code">list<></code> is too much space + overhead, and <code class="code"><rb_tree></code> exposes the red-black + tree classes used in the implementation of the standard maps and + sets. + </p><p>Each of the associative containers map, multimap, set, and multiset + have a counterpart which uses a + <a class="link" href="http://www.sgi.com/tech/stl/HashFunction.html">hashing + function</a> to do the arranging, instead of a strict weak ordering + function. The classes take as one of their template parameters a + function object that will return the hash value; by default, an + instantiation of + <a class="link" href="http://www.sgi.com/tech/stl/hash.html">hash</a>. + You should specialize this functor for your class, or define your own, + before trying to use one of the hashing classes. + </p><p>The hashing classes support all the usual associative container + functions, as well as some extra constructors specifying the number + of buckets, etc. + </p><p>Why would you want to use a hashing class instead of the + <span class="quote">“<span class="quote">normal</span>”</span>implementations? Matt Austern writes: + </p><div class="blockquote"><blockquote class="blockquote"><p> + <span class="emphasis"><em>[W]ith a well chosen hash function, hash tables + generally provide much better average-case performance than + binary search trees, and much worse worst-case performance. So + if your implementation has hash_map, if you don't mind using + nonstandard components, and if you aren't scared about the + possibility of pathological cases, you'll probably get better + performance from hash_map. + </em></span> + </p></blockquote></div></div><div class="navfooter"><hr/><table width="100%" summary="Navigation footer"><tr><td align="left"><a accesskey="p" href="bk01pt03ch21s02.html">Prev</a> </td><td align="center"><a accesskey="u" href="ext_containers.html">Up</a></td><td align="right"> <a accesskey="n" href="ext_utilities.html">Next</a></td></tr><tr><td align="left" valign="top">HP/SGI </td><td align="center"><a accesskey="h" href="../spine.html">Home</a></td><td align="right" valign="top"> Chapter 22. Utilities</td></tr></table></div></body></html> |