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103 lines
4.0 KiB
HTML
103 lines
4.0 KiB
HTML
4 years ago
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
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<head>
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<title>bsearch (The Red Hat newlib C Library)</title>
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<meta name="description" content="bsearch (The Red Hat newlib C Library)">
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<meta name="keywords" content="bsearch (The Red Hat newlib C Library)">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="Document-Index.html#Document-Index" rel="index" title="Document Index">
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<link href="Document-Index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Stdlib.html#Stdlib" rel="up" title="Stdlib">
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<link href="calloc.html#calloc" rel="next" title="calloc">
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<link href="atoll.html#atoll" rel="prev" title="atoll">
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</head>
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<body lang="en">
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<a name="bsearch"></a>
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<div class="header">
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<p>
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Next: <a href="calloc.html#calloc" accesskey="n" rel="next">calloc</a>, Previous: <a href="atoll.html#atoll" accesskey="p" rel="prev">atoll</a>, Up: <a href="Stdlib.html#Stdlib" accesskey="u" rel="up">Stdlib</a> [<a href="Document-Index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Document-Index.html#Document-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="bsearch_002d_002d_002dbinary-search"></a>
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<h3 class="section">2.10 <code>bsearch</code>—binary search</h3>
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<a name="index-bsearch"></a>
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<p><strong>Synopsis</strong>
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</p><div class="example">
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<pre class="example">#include <stdlib.h>
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void *bsearch(const void *<var>key</var>, const void *<var>base</var>,
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size_t <var>nmemb</var>, size_t <var>size</var>,
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int (*<var>compar</var>)(const void *, const void *));
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</pre></div>
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<p><strong>Description</strong><br>
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<code>bsearch</code> searches an array beginning at <var>base</var> for any element
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that matches <var>key</var>, using binary search. <var>nmemb</var> is the element
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count of the array; <var>size</var> is the size of each element.
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</p>
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<p>The array must be sorted in ascending order with respect to the
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comparison function <var>compar</var> (which you supply as the last argument of
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<code>bsearch</code>).
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</p>
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<p>You must define the comparison function <code>(*<var>compar</var>)</code> to have two
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arguments; its result must be negative if the first argument is
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less than the second, zero if the two arguments match, and
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positive if the first argument is greater than the second (where
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“less than” and “greater than” refer to whatever arbitrary
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ordering is appropriate).
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</p>
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<br>
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<p><strong>Returns</strong><br>
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Returns a pointer to an element of <var>array</var> that matches <var>key</var>. If
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more than one matching element is available, the result may point to
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any of them.
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</p>
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<br>
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<p><strong>Portability</strong><br>
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<code>bsearch</code> is ANSI.
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</p>
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<p>No supporting OS subroutines are required.
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</p>
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<br>
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</body>
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</html>
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