<html lang="en"> <head> <title>Looking Up or Entering a String - Untitled</title> <meta http-equiv="Content-Type" content="text/html"> <meta name="description" content="Untitled"> <meta name="generator" content="makeinfo 4.7"> <link title="Top" rel="start" href="index.html#Top"> <link rel="up" href="Hash-Tables.html#Hash-Tables" title="Hash Tables"> <link rel="prev" href="Creating-and-Freeing-a-Hash-Table.html#Creating-and-Freeing-a-Hash-Table" title="Creating and Freeing a Hash Table"> <link rel="next" href="Traversing-a-Hash-Table.html#Traversing-a-Hash-Table" title="Traversing a Hash Table"> <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> <!-- This file documents the BFD library. Copyright (C) 1991, 2000, 2001, 2003, 2006, 2007 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with the Invariant Sections being ``GNU General Public License'' and ``Funding Free Software'', the Front-Cover texts being (a) (see below), and with the Back-Cover Texts being (b) (see below). A copy of the license is included in the section entitled ``GNU Free Documentation License''. (a) The FSF's Front-Cover Text is: A GNU Manual (b) The FSF's Back-Cover Text is: You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development.--> <meta http-equiv="Content-Style-Type" content="text/css"> <style type="text/css"><!-- pre.display { font-family:inherit } pre.format { font-family:inherit } pre.smalldisplay { font-family:inherit; font-size:smaller } pre.smallformat { font-family:inherit; font-size:smaller } pre.smallexample { font-size:smaller } pre.smalllisp { font-size:smaller } span.sc { font-variant:small-caps } span.roman { font-family: serif; font-weight: normal; } --></style> </head> <body> <div class="node"> <p> <a name="Looking-Up-or-Entering-a-String"></a>Next: <a rel="next" accesskey="n" href="Traversing-a-Hash-Table.html#Traversing-a-Hash-Table">Traversing a Hash Table</a>, Previous: <a rel="previous" accesskey="p" href="Creating-and-Freeing-a-Hash-Table.html#Creating-and-Freeing-a-Hash-Table">Creating and Freeing a Hash Table</a>, Up: <a rel="up" accesskey="u" href="Hash-Tables.html#Hash-Tables">Hash Tables</a> <hr><br> </div> <h4 class="subsection">2.18.2 Looking up or entering a string</h4> <p><a name="index-bfd_005fhash_005flookup-1388"></a>The function <code>bfd_hash_lookup</code> is used both to look up a string in the hash table and to create a new entry. <p>If the <var>create</var> argument is <code>FALSE</code>, <code>bfd_hash_lookup</code> will look up a string. If the string is found, it will returns a pointer to a <code>struct bfd_hash_entry</code>. If the string is not found in the table <code>bfd_hash_lookup</code> will return <code>NULL</code>. You should not modify any of the fields in the returns <code>struct bfd_hash_entry</code>. <p>If the <var>create</var> argument is <code>TRUE</code>, the string will be entered into the hash table if it is not already there. Either way a pointer to a <code>struct bfd_hash_entry</code> will be returned, either to the existing structure or to a newly created one. In this case, a <code>NULL</code> return means that an error occurred. <p>If the <var>create</var> argument is <code>TRUE</code>, and a new entry is created, the <var>copy</var> argument is used to decide whether to copy the string onto the hash table objalloc or not. If <var>copy</var> is passed as <code>FALSE</code>, you must be careful not to deallocate or modify the string as long as the hash table exists. </body></html>