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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"><title>Hash Tables</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2"><link rel="start" href="index.html" title="GLib Reference Manual"><link rel="up" href="glib-data-types.html" title="GLib Data Types"><link rel="prev" href="glib-Trash-Stacks.html" title="Trash Stacks"><link rel="next" href="glib-Strings.html" title="Strings"><meta name="generator" content="GTK-Doc V1.9 (XML mode)"><link rel="stylesheet" href="style.css" type="text/css"><link rel="chapter" href="glib.html" title="GLib Overview"><link rel="chapter" href="glib-fundamentals.html" title="GLib Fundamentals"><link rel="chapter" href="glib-core.html" title="GLib Core Application Support"><link rel="chapter" href="glib-utilities.html" title="GLib Utilities"><link rel="chapter" href="glib-data-types.html" title="GLib Data Types"><link rel="chapter" 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href="glib-Trash-Stacks.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td><td><a accesskey="u" href="glib-data-types.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td><td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td><th width="100%" align="center">GLib Reference Manual</th><td><a accesskey="n" href="glib-Strings.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td></tr><tr><td colspan="5" class="shortcuts"><nobr><a href="#id3287160" class="shortcut">Top</a>  |  <a href="#id3288266" class="shortcut">Description</a></nobr></td></tr></table><div class="refentry" lang="en"><a name="glib-Hash-Tables"></a><div class="titlepage"></div><div class="refnamediv"><table width="100%"><tr><td valign="top"><h2><a name="id3287160"></a><span class="refentrytitle">Hash Tables</span></h2><p>Hash Tables — associations between keys and values so that given a key the valuecan be found quickly</p></td><td valign="top" align="right"></td></tr></table></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">#include <glib.h> <a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a>;<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a>* <a class="link" href="glib-Hash-Tables.html#g-hash-table-new">g_hash_table_new</a> (<a class="link" href="glib-Hash-Tables.html#GHashFunc">GHashFunc</a> hash_func, <a class="link" href="glib-Hash-Tables.html#GEqualFunc">GEqualFunc</a> key_equal_func);<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a>* <a class="link" href="glib-Hash-Tables.html#g-hash-table-new-full">g_hash_table_new_full</a> (<a class="link" href="glib-Hash-Tables.html#GHashFunc">GHashFunc</a> hash_func, <a class="link" href="glib-Hash-Tables.html#GEqualFunc">GEqualFunc</a> key_equal_func, <a class="link" href="glib-Datasets.html#GDestroyNotify">GDestroyNotify</a> key_destroy_func, <a class="link" href="glib-Datasets.html#GDestroyNotify">GDestroyNotify</a> value_destroy_func);<a class="link" href="glib-Basic-Types.html#guint">guint</a> (<a class="link" href="glib-Hash-Tables.html#GHashFunc">*GHashFunc</a>) (<a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> key);<a class="link" href="glib-Basic-Types.html#gboolean">gboolean</a> (<a class="link" href="glib-Hash-Tables.html#GEqualFunc">*GEqualFunc</a>) (<a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> a, <a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> b);void <a class="link" href="glib-Hash-Tables.html#g-hash-table-insert">g_hash_table_insert</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> key, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> value);void <a class="link" href="glib-Hash-Tables.html#g-hash-table-replace">g_hash_table_replace</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> key, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> value);<a class="link" href="glib-Basic-Types.html#guint">guint</a> <a class="link" href="glib-Hash-Tables.html#g-hash-table-size">g_hash_table_size</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table);<a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> <a class="link" href="glib-Hash-Tables.html#g-hash-table-lookup">g_hash_table_lookup</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table, <a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> key);<a class="link" href="glib-Basic-Types.html#gboolean">gboolean</a> <a class="link" href="glib-Hash-Tables.html#g-hash-table-lookup-extended">g_hash_table_lookup_extended</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table, <a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> lookup_key, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> *orig_key, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> *value);void <a class="link" href="glib-Hash-Tables.html#g-hash-table-foreach">g_hash_table_foreach</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table, <a class="link" href="glib-Hash-Tables.html#GHFunc">GHFunc</a> func, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> user_data);<a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> <a class="link" href="glib-Hash-Tables.html#g-hash-table-find">g_hash_table_find</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table, <a class="link" href="glib-Hash-Tables.html#GHRFunc">GHRFunc</a> predicate, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> user_data);void (<a class="link" href="glib-Hash-Tables.html#GHFunc">*GHFunc</a>) (<a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> key, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> value, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> user_data);<a class="link" href="glib-Basic-Types.html#gboolean">gboolean</a> <a class="link" href="glib-Hash-Tables.html#g-hash-table-remove">g_hash_table_remove</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table, <a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> key);<a class="link" href="glib-Basic-Types.html#gboolean">gboolean</a> <a class="link" href="glib-Hash-Tables.html#g-hash-table-steal">g_hash_table_steal</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table, <a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> key);<a class="link" href="glib-Basic-Types.html#guint">guint</a> <a class="link" href="glib-Hash-Tables.html#g-hash-table-foreach-remove">g_hash_table_foreach_remove</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table, <a class="link" href="glib-Hash-Tables.html#GHRFunc">GHRFunc</a> func, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> user_data);<a class="link" href="glib-Basic-Types.html#guint">guint</a> <a class="link" href="glib-Hash-Tables.html#g-hash-table-foreach-steal">g_hash_table_foreach_steal</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table, <a class="link" href="glib-Hash-Tables.html#GHRFunc">GHRFunc</a> func, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> user_data);void <a class="link" href="glib-Hash-Tables.html#g-hash-table-remove-all">g_hash_table_remove_all</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table);void <a class="link" href="glib-Hash-Tables.html#g-hash-table-steal-all">g_hash_table_steal_all</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table);<a class="link" href="glib-Doubly-Linked-Lists.html#GList">GList</a>* <a class="link" href="glib-Hash-Tables.html#g-hash-table-get-keys">g_hash_table_get_keys</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table);<a class="link" href="glib-Doubly-Linked-Lists.html#GList">GList</a>* <a class="link" href="glib-Hash-Tables.html#g-hash-table-get-values">g_hash_table_get_values</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table);<a class="link" href="glib-Basic-Types.html#gboolean">gboolean</a> (<a class="link" href="glib-Hash-Tables.html#GHRFunc">*GHRFunc</a>) (<a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> key, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> value, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> user_data);#define <a class="link" href="glib-Hash-Tables.html#g-hash-table-freeze">g_hash_table_freeze</a> (hash_table)#define <a class="link" href="glib-Hash-Tables.html#g-hash-table-thaw">g_hash_table_thaw</a> (hash_table)void <a class="link" href="glib-Hash-Tables.html#g-hash-table-destroy">g_hash_table_destroy</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table);<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a>* <a class="link" href="glib-Hash-Tables.html#g-hash-table-ref">g_hash_table_ref</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table);void <a class="link" href="glib-Hash-Tables.html#g-hash-table-unref">g_hash_table_unref</a> (<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table); <a class="link" href="glib-Hash-Tables.html#GHashTableIter">GHashTableIter</a>;void <a class="link" href="glib-Hash-Tables.html#g-hash-table-iter-init">g_hash_table_iter_init</a> (<a class="link" href="glib-Hash-Tables.html#GHashTableIter">GHashTableIter</a> *iter, <a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a> *hash_table);<a class="link" href="glib-Basic-Types.html#gboolean">gboolean</a> <a class="link" href="glib-Hash-Tables.html#g-hash-table-iter-next">g_hash_table_iter_next</a> (<a class="link" href="glib-Hash-Tables.html#GHashTableIter">GHashTableIter</a> *iter, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> *key, <a class="link" href="glib-Basic-Types.html#gpointer">gpointer</a> *value);<a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a>* <a class="link" href="glib-Hash-Tables.html#g-hash-table-iter-get-hash-table">g_hash_table_iter_get_hash_table</a> (<a class="link" href="glib-Hash-Tables.html#GHashTableIter">GHashTableIter</a> *iter);void <a class="link" href="glib-Hash-Tables.html#g-hash-table-iter-remove">g_hash_table_iter_remove</a> (<a class="link" href="glib-Hash-Tables.html#GHashTableIter">GHashTableIter</a> *iter);void <a class="link" href="glib-Hash-Tables.html#g-hash-table-iter-steal">g_hash_table_iter_steal</a> (<a class="link" href="glib-Hash-Tables.html#GHashTableIter">GHashTableIter</a> *iter);<a class="link" href="glib-Basic-Types.html#gboolean">gboolean</a> <a class="link" href="glib-Hash-Tables.html#g-direct-equal">g_direct_equal</a> (<a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> v1, <a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> v2);<a class="link" href="glib-Basic-Types.html#guint">guint</a> <a class="link" href="glib-Hash-Tables.html#g-direct-hash">g_direct_hash</a> (<a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> v);<a class="link" href="glib-Basic-Types.html#gboolean">gboolean</a> <a class="link" href="glib-Hash-Tables.html#g-int-equal">g_int_equal</a> (<a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> v1, <a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> v2);<a class="link" href="glib-Basic-Types.html#guint">guint</a> <a class="link" href="glib-Hash-Tables.html#g-int-hash">g_int_hash</a> (<a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> v);<a class="link" href="glib-Basic-Types.html#gboolean">gboolean</a> <a class="link" href="glib-Hash-Tables.html#g-str-equal">g_str_equal</a> (<a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> v1, <a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> v2);<a class="link" href="glib-Basic-Types.html#guint">guint</a> <a class="link" href="glib-Hash-Tables.html#g-str-hash">g_str_hash</a> (<a class="link" href="glib-Basic-Types.html#gconstpointer">gconstpointer</a> v);</pre></div><div class="refsect1" lang="en"><a name="id3288266"></a><h2>Description</h2><p>A <a class="link" href="glib-Hash-Tables.html#GHashTable"><span class="type">GHashTable</span></a> provides associations between keys and values whichis optimized so that given a key, the associated value can be foundvery quickly.</p><p>Note that neither keys nor values are copied when inserted into the<a class="link" href="glib-Hash-Tables.html#GHashTable"><span class="type">GHashTable</span></a>, so they must exist for the lifetime of the <a class="link" href="glib-Hash-Tables.html#GHashTable"><span class="type">GHashTable</span></a>.This means that the use of static strings is OK, but temporarystrings (i.e. those created in buffers and those returned by GTK+ widgets)should be copied with <a class="link" href="glib-String-Utility-Functions.html#g-strdup"><code class="function">g_strdup()</code></a> before being inserted.</p><p>If keys or values are dynamically allocated, you must be careful to ensurethat they are freed when they are removed from the <a class="link" href="glib-Hash-Tables.html#GHashTable"><span class="type">GHashTable</span></a>, and alsowhen they are overwritten by new insertions into the <a class="link" href="glib-Hash-Tables.html#GHashTable"><span class="type">GHashTable</span></a>.It is also not advisable to mix static strings and dynamically-allocatedstrings in a <a class="link" href="glib-Hash-Tables.html#GHashTable"><span class="type">GHashTable</span></a>, because it then becomes difficult to determinewhether the string should be freed.</p><p>To create a <a class="link" href="glib-Hash-Tables.html#GHashTable"><span class="type">GHashTable</span></a>, use <a class="link" href="glib-Hash-Tables.html#g-hash-table-new"><code class="function">g_hash_table_new()</code></a>.</p><p>To insert a key and value into a <a class="link" href="glib-Hash-Tables.html#GHashTable"><span class="type">GHashTable</span></a>, use <a class="link" href="glib-Hash-Tables.html#g-hash-table-insert"><code class="function">g_hash_table_insert()</code></a>.</p><p>To lookup a value corresponding to a given key, use <a class="link" href="glib-Hash-Tables.html#g-hash-table-lookup"><code class="function">g_hash_table_lookup()</code></a>and <a class="link" href="glib-Hash-Tables.html#g-hash-table-lookup-extended"><code class="function">g_hash_table_lookup_extended()</code></a>.</p><p>To remove a key and value, use <a class="link" href="glib-Hash-Tables.html#g-hash-table-remove"><code class="function">g_hash_table_remove()</code></a>.</p><p>To call a function for each key and value pair use <a class="link" href="glib-Hash-Tables.html#g-hash-table-foreach"><code class="function">g_hash_table_foreach()</code></a>or use a iterator to iterate over the key/value pairs in the hash table, see<a class="link" href="glib-Hash-Tables.html#GHashTableIter"><span class="type">GHashTableIter</span></a>.</p><p>To destroy a <a class="link" href="glib-Hash-Tables.html#GHashTable"><span class="type">GHashTable</span></a> use <a class="link" href="glib-Hash-Tables.html#g-hash-table-destroy"><code class="function">g_hash_table_destroy()</code></a>.</p></div><div class="refsect1" lang="en"><a name="id3288490"></a><h2>Details</h2><div class="refsect2" lang="en"><a name="id3288500"></a><h3><a name="GHashTable"></a>GHashTable</h3><a class="indexterm" name="id3288512"></a><pre class="programlisting">typedef struct _GHashTable GHashTable;</pre><p>The <span class="structname">GHashTable</span> struct is an opaque data structure to represent a<a class="link" href="glib-Hash-Tables.html" title="Hash Tables">Hash Table</a>.It should only be accessed via the following functions.</p></div><hr><div class="refsect2" lang="en"><a name="id3288542"></a><h3><a name="g-hash-table-new"></a>g_hash_table_new ()</h3><a class="indexterm" name="id3288554"></a><pre class="programlisting"><a class="link" href="glib-Hash-Tables.html#GHashTable">GHashTable</a>* g_hash_table_new (<a class="link" href="glib-Hash-Tables.html#GHashFunc">GHashFunc</a> hash_func, <a class="link" href="glib-Hash-Tables.html#GEqualFunc">GEqualFunc</a> key_equal_func);</pre><p>Creates a new <a class="link" href="glib-Hash-Tables.html#GHashTable"><span class="type">GHashTable</span></a> with a reference count of 1.</p><p></p><div class="variablelist"><table border="0"><col align="left" valign="top"><tbody><tr><td><p><span class="term"><em class="parameter"><code>hash_func</code></em> :</span></p></td><td> a function to create a hash value from a key. Hash values are used to determine where keys are stored within the <a class="link" href="glib-Hash-Tables.html#GHashTable"><span class="type">GHashTable</span></a> data structure. The <a class="link" href="glib-Hash-Tables.html#g-direct-hash"><code class="function">g_direct_hash()</code></a>, <a class="link" href="glib-Hash-Tables.html#g-int-hash"><code class="function">g_int_hash()</code></a> and⌨️ 快捷键说明
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