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<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Memory Allocators</title><meta name="generator" content="DocBook XSL Stylesheets V1.65.1"><link rel="home" href="index.html" title="GLib Reference Manual"><link rel="up" href="glib-data-types.html" title="GLib Data Types"><link rel="previous" href="glib-Caches.html" title="Caches"><link rel="next" href="tools.html" title="GLib Tools"><link rel="chapter" href="glib.html" title="GLib Overview"><link rel="refentry" href="glib-building.html" title="Compiling the GLib package"><link rel="refentry" href="glib-cross-compiling.html" title="Cross-compiling the GLib package"><link rel="refentry" href="glib-compiling.html" title="Compiling GLib Applications"><link rel="refentry" href="glib-running.html" title="Running GLib Applications"><link rel="refentry" href="glib-changes.html" title="Changes to GLib"><link rel="refentry" href="glib-resources.html" title="Mailing lists and bug reports"><link rel="chapter" href="glib-fundamentals.html" title="GLib Fundamentals"><link rel="refentry" href="glib-Basic-Types.html" title="Basic Types"><link rel="refentry" href="glib-Limits-of-Basic-Types.html" title="Limits of Basic Types"><link rel="refentry" href="glib-Standard-Macros.html" title="Standard Macros"><link rel="refentry" href="glib-Type-Conversion-Macros.html" title="Type Conversion Macros"><link rel="refentry" href="glib-Byte-Order-Macros.html" title="Byte Order Macros"><link rel="refentry" href="glib-Numerical-Definitions.html" title="Numerical Definitions"><link rel="refentry" href="glib-Miscellaneous-Macros.html" title="Miscellaneous Macros"><link rel="refentry" href="glib-Atomic-Operations.html" title="Atomic Operations"><link rel="chapter" href="glib-core.html" title="GLib Core Application Support"><link rel="refentry" href="glib-The-Main-Event-Loop.html" title="The Main Event Loop"><link rel="refentry" href="glib-Threads.html" title="
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href="glib-Memory-Allocators.html#id3341392" title="Description"><link rel="section" href="glib-Memory-Allocators.html#id3341625" title="Details"><meta name="generator" content="GTK-Doc V1.2 (XML mode)"><link rel="stylesheet" href="style.css" type="text/css"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><table class="navigation" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2"><tr valign="middle"><td><a accesskey="p" href="glib-Caches.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="tools.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td></tr></table><div class="refentry" lang="en"><a name="glib-Memory-Allocators"></a><div class="titlepage"><div></div><div></div></div><div class="refnamediv"><h2><span class="refentrytitle">Memory Allocators</span></h2><p>Memory Allocators — allocates chunks of memory for <a href="glib-Doubly-Linked-Lists.html#GList"><span class="type">GList</span></a>, <a href="glib-Singly-Linked-Lists.html#GSList"><span class="type">GSList</span></a> and <a href="glib-N-ary-Trees.html#GNode"><span class="type">GNode</span></a>.</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">
#include <glib.h>
struct <a href="glib-Memory-Allocators.html#GAllocator">GAllocator</a>;
<a href="glib-Memory-Allocators.html#GAllocator">GAllocator</a>* <a href="glib-Memory-Allocators.html#g-allocator-new">g_allocator_new</a> (const <a href="glib-Basic-Types.html#gchar">gchar</a> *name,
<a href="glib-Basic-Types.html#guint">guint</a> n_preallocs);
void <a href="glib-Memory-Allocators.html#g-allocator-free">g_allocator_free</a> (<a href="glib-Memory-Allocators.html#GAllocator">GAllocator</a> *allocator);
</pre></div><div class="refsect1" lang="en"><a name="id3341392"></a><h2>Description</h2><p>
The <a href="glib-Memory-Allocators.html#GAllocator"><span class="type">GAllocator</span></a> is used as an efficient way to allocate small pieces of
memory for use with the <a href="glib-Doubly-Linked-Lists.html#GList"><span class="type">GList</span></a>, <a href="glib-Singly-Linked-Lists.html#GSList"><span class="type">GSList</span></a> and <a href="glib-N-ary-Trees.html#GNode"><span class="type">GNode</span></a> data structures.
It uses a <a href="glib-Memory-Chunks.html#GMemChunk"><span class="type">GMemChunk</span></a> so elements are allocated in groups, rather than
individually.
</p><p>
The <a href="glib-Doubly-Linked-Lists.html#GList"><span class="type">GList</span></a>, <a href="glib-Singly-Linked-Lists.html#GSList"><span class="type">GSList</span></a> and <a href="glib-N-ary-Trees.html#GNode"><span class="type">GNode</span></a> implementations create default <a href="glib-Memory-Allocators.html#GAllocator"><span class="type">GAllocator</span></a>
objects, which are probably sufficient for most purposes. These default
allocators use blocks of 128 elements.
</p><p>
To use your own <a href="glib-Memory-Allocators.html#GAllocator"><span class="type">GAllocator</span></a>, create it with <a href="glib-Memory-Allocators.html#g-allocator-new"><tt class="function">g_allocator_new()</tt></a>. Then
use <a href="glib-Doubly-Linked-Lists.html#g-list-push-allocator"><tt class="function">g_list_push_allocator()</tt></a>, <a href="glib-Singly-Linked-Lists.html#g-slist-push-allocator"><tt class="function">g_slist_push_allocator()</tt></a> or
<a href="glib-N-ary-Trees.html#g-node-push-allocator"><tt class="function">g_node_push_allocator()</tt></a> before any code which allocates new <a href="glib-Doubly-Linked-Lists.html#GList"><span class="type">GList</span></a>, <a href="glib-Singly-Linked-Lists.html#GSList"><span class="type">GSList</span></a>
or <a href="glib-N-ary-Trees.html#GNode"><span class="type">GNode</span></a> elements respectively. After allocating the new elements, you must
use <a href="glib-Doubly-Linked-Lists.html#g-list-pop-allocator"><tt class="function">g_list_pop_allocator()</tt></a>, <a href="glib-Singly-Linked-Lists.html#g-slist-pop-allocator"><tt class="function">g_slist_pop_allocator()</tt></a> or <a href="glib-N-ary-Trees.html#g-node-pop-allocator"><tt class="function">g_node_pop_allocator()</tt></a>
to restore the previous allocators.
</p><p>
Note that you cannot use the same allocator for <a href="glib-Doubly-Linked-Lists.html#GList"><span class="type">GList</span></a>, <a href="glib-Singly-Linked-Lists.html#GSList"><span class="type">GSList</span></a> and <a href="glib-N-ary-Trees.html#GNode"><span class="type">GNode</span></a>
elements. Each must use separate allocators.
</p></div><div class="refsect1" lang="en"><a name="id3341625"></a><h2>Details</h2><div class="refsect2" lang="en"><a name="id3341630"></a><h3><a name="GAllocator"></a>struct GAllocator</h3><a class="indexterm" name="id3341641"></a><pre class="programlisting">struct GAllocator;</pre><p>
The <span class="structname">GAllocator</span> struct contains private data. and should only be accessed
using the following functions.
</p></div><hr><div class="refsect2" lang="en"><a name="id3341661"></a><h3><a name="g-allocator-new"></a>g_allocator_new ()</h3><a class="indexterm" name="id3341672"></a><pre class="programlisting"><a href="glib-Memory-Allocators.html#GAllocator">GAllocator</a>* g_allocator_new (const <a href="glib-Basic-Types.html#gchar">gchar</a> *name,
<a href="glib-Basic-Types.html#guint">guint</a> n_preallocs);</pre><p>
Creates a new <a href="glib-Memory-Allocators.html#GAllocator"><span class="type">GAllocator</span></a>.
</p><div class="variablelist"><table border="0"><col align="left" valign="top"><tbody><tr><td><span class="term"><i class="parameter"><tt>name</tt></i> :</span></td><td>the name of the <a href="glib-Memory-Allocators.html#GAllocator"><span class="type">GAllocator</span></a>. This name is used to set the name of the
<a href="glib-Memory-Chunks.html#GMemChunk"><span class="type">GMemChunk</span></a> used by the <a href="glib-Memory-Allocators.html#GAllocator"><span class="type">GAllocator</span></a>, and is only used for debugging.
</td></tr><tr><td><span class="term"><i class="parameter"><tt>n_preallocs</tt></i> :</span></td><td>the number of elements in each block of memory allocated.
Larger blocks mean less calls to <a href="glib-Memory-Allocation.html#g-malloc"><tt class="function">g_malloc()</tt></a>, but some memory may be wasted.
(GLib uses 128 elements per block by default.) The value must be between 1
and 65535.
</td></tr><tr><td><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></td><td>a new <a href="glib-Memory-Allocators.html#GAllocator"><span class="type">GAllocator</span></a>.
</td></tr></tbody></table></div></div><hr><div class="refsect2" lang="en"><a name="id3341804"></a><h3><a name="g-allocator-free"></a>g_allocator_free ()</h3><a class="indexterm" name="id3341815"></a><pre class="programlisting">void g_allocator_free (<a href="glib-Memory-Allocators.html#GAllocator">GAllocator</a> *allocator);</pre><p>
Frees all of the memory allocated by the <a href="glib-Memory-Allocators.html#GAllocator"><span class="type">GAllocator</span></a>.
</p><div class="variablelist"><table border="0"><col align="left" valign="top"><tbody><tr><td><span class="term"><i class="parameter"><tt>allocator</tt></i> :</span></td><td>a <a href="glib-Memory-Allocators.html#GAllocator"><span class="type">GAllocator</span></a>.
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