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<title>Reference Counting and Memory Mangement: GDK-PixBuf Reference Manual</title>
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<a name="gdk-pixbuf-Reference-Counting-and-Memory-Mangement"></a><div class="titlepage"></div>
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<h2><span class="refentrytitle"><a name="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.top_of_page"></a>Reference Counting and Memory Mangement</span></h2>
<p>Reference Counting and Memory Mangement — Functions for reference counting and memory management on pixbufs.</p>
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<div class="refsect1">
<a name="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.functions"></a><h2>Functions</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="functions_return">
<col class="functions_name">
</colgroup>
<tbody>
<tr>
<td class="function_type">
<a class="link" href="gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="returnvalue">GdkPixbuf</span></a> *
</td>
<td class="function_name">
<a class="link" href="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.html#gdk-pixbuf-ref" title="gdk_pixbuf_ref ()">gdk_pixbuf_ref</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.html#gdk-pixbuf-unref" title="gdk_pixbuf_unref ()">gdk_pixbuf_unref</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<span class="c_punctuation">(</span><a class="link" href="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.html#GdkPixbufDestroyNotify" title="GdkPixbufDestroyNotify ()">*GdkPixbufDestroyNotify</a><span class="c_punctuation">)</span> <span class="c_punctuation">()</span>
</td>
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</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.includes"></a><h2>Includes</h2>
<pre class="synopsis">#include <gdk-pixbuf/gdk-pixbuf.h>
</pre>
</div>
<div class="refsect1">
<a name="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.description"></a><h2>Description</h2>
<p><a class="link" href="gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a> structures are reference counted. This means that an
application can share a single pixbuf among many parts of the
code. When a piece of the program needs to keep a pointer to a
pixbuf, it should add a reference to it by calling <a href="../gobject/gobject-The-Base-Object-Type.html#g-object-ref"><code class="function">g_object_ref()</code></a>.
When it no longer needs the pixbuf, it should subtract a reference
by calling <a href="../gobject/gobject-The-Base-Object-Type.html#g-object-unref"><code class="function">g_object_unref()</code></a>. The pixbuf will be destroyed when
its reference count drops to zero. Newly-created <a class="link" href="gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a>
structures start with a reference count of one.</p>
<div class="blockquote"><blockquote class="blockquote"><p>As <a class="link" href="gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a> is derived from <a href="../gobject/gobject-The-Base-Object-Type.html#GObject-struct"><span class="type">GObject</span></a> now, <a class="link" href="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.html#gdk-pixbuf-ref" title="gdk_pixbuf_ref ()"><code class="function">gdk_pixbuf_ref()</code></a> and
<a class="link" href="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.html#gdk-pixbuf-unref" title="gdk_pixbuf_unref ()"><code class="function">gdk_pixbuf_unref()</code></a> are deprecated in favour of <a href="../gobject/gobject-The-Base-Object-Type.html#g-object-ref"><code class="function">g_object_ref()</code></a>
and <a href="../gobject/gobject-The-Base-Object-Type.html#g-object-unref"><code class="function">g_object_unref()</code></a> resp.</p></blockquote></div>
<p>Finalizing a pixbuf means to free its pixel data and to free the
<a class="link" href="gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a> structure itself. Most of the library functions that
create <a class="link" href="gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a> structures create the pixel data by themselves
and define the way it should be freed; you do not need to worry
about those.</p>
<p>To provide preallocated pixel data, use
<a class="link" href="gdk-pixbuf-Image-Data-in-Memory.html#gdk-pixbuf-new-from-bytes" title="gdk_pixbuf_new_from_bytes ()"><code class="function">gdk_pixbuf_new_from_bytes()</code></a>. The <a class="link" href="gdk-pixbuf-Image-Data-in-Memory.html#gdk-pixbuf-new-from-data" title="gdk_pixbuf_new_from_data ()"><code class="function">gdk_pixbuf_new_from_data()</code></a> API is
an older variant that predates the existence of <a href="../glib/glib-Byte-Arrays.html#GBytes"><span class="type">GBytes</span></a>.</p>
</div>
<div class="refsect1">
<a name="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.functions_details"></a><h2>Functions</h2>
<div class="refsect2">
<a name="gdk-pixbuf-ref"></a><h3>gdk_pixbuf_ref ()</h3>
<pre class="programlisting"><a class="link" href="gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="returnvalue">GdkPixbuf</span></a> *
gdk_pixbuf_ref (<em class="parameter"><code><a class="link" href="gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a> *pixbuf</code></em>);</pre>
<div class="warning">
<p><code class="literal">gdk_pixbuf_ref</code> has been deprecated since version 2.0 and should not be used in newly-written code.</p>
<p>Use <a href="../gobject/gobject-The-Base-Object-Type.html#g-object-ref"><code class="function">g_object_ref()</code></a>.</p>
</div>
<p>Adds a reference to a pixbuf.</p>
<p><span class="annotation">[<acronym title="Exposed in C code, not necessarily available in other languages."><span class="acronym">skip</span></acronym>]</span></p>
<div class="refsect3">
<a name="gdk-pixbuf-ref.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>pixbuf</p></td>
<td class="parameter_description"><p>A pixbuf.</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gdk-pixbuf-ref.returns"></a><h4>Returns</h4>
<p> The same as the <em class="parameter"><code>pixbuf</code></em>
argument.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gdk-pixbuf-unref"></a><h3>gdk_pixbuf_unref ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gdk_pixbuf_unref (<em class="parameter"><code><a class="link" href="gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a> *pixbuf</code></em>);</pre>
<div class="warning">
<p><code class="literal">gdk_pixbuf_unref</code> has been deprecated since version 2.0 and should not be used in newly-written code.</p>
<p>Use <a href="../gobject/gobject-The-Base-Object-Type.html#g-object-unref"><code class="function">g_object_unref()</code></a>.</p>
</div>
<p>Removes a reference from a pixbuf.</p>
<p><span class="annotation">[<acronym title="Exposed in C code, not necessarily available in other languages."><span class="acronym">skip</span></acronym>]</span></p>
<div class="refsect3">
<a name="gdk-pixbuf-unref.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>pixbuf</p></td>
<td class="parameter_description"><p>A pixbuf.</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="GdkPixbufDestroyNotify"></a><h3>GdkPixbufDestroyNotify ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
<span class="c_punctuation">(</span>*GdkPixbufDestroyNotify<span class="c_punctuation">)</span> (<em class="parameter"><code><a href="../glib/glib-Basic-Types.html#guchar"><span class="type">guchar</span></a> *pixels</code></em>,
<em class="parameter"><code><a href="../glib/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> data</code></em>);</pre>
<p>A function of this type is responsible for freeing the pixel array
of a pixbuf. The <a class="link" href="gdk-pixbuf-Image-Data-in-Memory.html#gdk-pixbuf-new-from-data" title="gdk_pixbuf_new_from_data ()"><code class="function">gdk_pixbuf_new_from_data()</code></a> function lets you
pass in a pre-allocated pixel array so that a pixbuf can be
created from it; in this case you will need to pass in a function
of <a class="link" href="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.html#GdkPixbufDestroyNotify" title="GdkPixbufDestroyNotify ()"><span class="type">GdkPixbufDestroyNotify</span></a> so that the pixel data can be freed
when the pixbuf is finalized.</p>
<div class="refsect3">
<a name="GdkPixbufDestroyNotify.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>pixels</p></td>
<td class="parameter_description"><p> The pixel array of the pixbuf
that is being finalized. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym>][<acronym title="Generics and defining elements of containers and arrays."><span class="acronym">element-type</span></acronym> guint8]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>data</p></td>
<td class="parameter_description"><p> User closure data. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="This parameter is a 'user_data', for callbacks; many bindings can pass NULL here."><span class="acronym">closure</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
</div>
</div>
<div class="refsect1">
<a name="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.other_details"></a><h2>Types and Values</h2>
</div>
<div class="refsect1">
<a name="gdk-pixbuf-Reference-Counting-and-Memory-Mangement.see-also"></a><h2>See Also</h2>
<p><a class="link" href="gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a>, <a class="link" href="gdk-pixbuf-Image-Data-in-Memory.html#gdk-pixbuf-new-from-data" title="gdk_pixbuf_new_from_data ()"><code class="function">gdk_pixbuf_new_from_data()</code></a>.</p>
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