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110 lines
4.9 KiB
HTML
110 lines
4.9 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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<!-- This file documents the BFD library.
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Copyright (C) 1991-2019 Free Software Foundation, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with the
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Invariant Sections being "GNU General Public License" and "Funding
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Free Software", the Front-Cover texts being (a) (see below), and with
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the Back-Cover Texts being (b) (see below). A copy of the license is
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included in the section entitled "GNU Free Documentation License".
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(a) The FSF's Front-Cover Text is:
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A GNU Manual
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(b) The FSF's Back-Cover Text is:
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You have freedom to copy and modify this GNU Manual, like GNU
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software. Copies published by the Free Software Foundation raise
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funds for GNU development. -->
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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>Looking Up or Entering a String (Untitled Document)</title>
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<meta name="description" content="Looking Up or Entering a String (Untitled Document)">
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<meta name="keywords" content="Looking Up or Entering a String (Untitled Document)">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content="makeinfo">
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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="BFD-Index.html#BFD-Index" rel="index" title="BFD Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Hash-Tables.html#Hash-Tables" rel="up" title="Hash Tables">
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<link href="Traversing-a-Hash-Table.html#Traversing-a-Hash-Table" rel="next" title="Traversing a Hash Table">
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<link href="Creating-and-Freeing-a-Hash-Table.html#Creating-and-Freeing-a-Hash-Table" rel="prev" title="Creating and Freeing a Hash Table">
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<style type="text/css">
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a.summary-letter {text-decoration: none}
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pre.display {font-family: inherit}
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pre.format {font-family: inherit}
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span.roman {font-family: initial; font-weight: normal}
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span.sansserif {font-family: sans-serif; font-weight: normal}
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ul.no-bullet {list-style: none}
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-->
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</style>
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</head>
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<body lang="en">
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<a name="Looking-Up-or-Entering-a-String"></a>
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<div class="header">
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<p>
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Next: <a href="Traversing-a-Hash-Table.html#Traversing-a-Hash-Table" accesskey="n" rel="next">Traversing a Hash Table</a>, Previous: <a href="Creating-and-Freeing-a-Hash-Table.html#Creating-and-Freeing-a-Hash-Table" accesskey="p" rel="prev">Creating and Freeing a Hash Table</a>, Up: <a href="Hash-Tables.html#Hash-Tables" accesskey="u" rel="up">Hash Tables</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="BFD-Index.html#BFD-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Looking-up-or-entering-a-string"></a>
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<h4 class="subsection">2.18.2 Looking up or entering a string</h4>
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<a name="index-bfd_005fhash_005flookup"></a>
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<p>The function <code>bfd_hash_lookup</code> is used both to look up a
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string in the hash table and to create a new entry.
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</p>
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<p>If the <var>create</var> argument is <code>FALSE</code>, <code>bfd_hash_lookup</code>
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will look up a string. If the string is found, it will
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returns a pointer to a <code>struct bfd_hash_entry</code>. If the
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string is not found in the table <code>bfd_hash_lookup</code> will
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return <code>NULL</code>. You should not modify any of the fields in
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the returns <code>struct bfd_hash_entry</code>.
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</p>
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<p>If the <var>create</var> argument is <code>TRUE</code>, the string will be
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entered into the hash table if it is not already there.
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Either way a pointer to a <code>struct bfd_hash_entry</code> will be
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returned, either to the existing structure or to a newly
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created one. In this case, a <code>NULL</code> return means that an
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error occurred.
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</p>
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<p>If the <var>create</var> argument is <code>TRUE</code>, and a new entry is
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created, the <var>copy</var> argument is used to decide whether to
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copy the string onto the hash table objalloc or not. If
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<var>copy</var> is passed as <code>FALSE</code>, you must be careful not to
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deallocate or modify the string as long as the hash table
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exists.
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</p>
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</body>
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</html>
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