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<!-- ##### SECTION Title ##### -->
Reference Counting and Memory Mangement
<!-- ##### SECTION Short_Description ##### -->
Functions to perform reference counting and memory management on a
#GdkPixbuf.
<!-- ##### SECTION Long_Description ##### -->
<para>
#GdkPixbuf 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. When it no longer needs
the pixbuf, it should subtract a reference. The pixbuf will be
destroyed when its reference count drops to zero. Newly-created
#GdkPixbuf structures start with a reference count of one.
</para>
<para>
<emphasis>Finalizing</emphasis> a pixbuf means to free its pixel
data and to free the #GdkPixbuf structure itself. Most of the
library functions that create #GdkPixbuf structures create the
pixel data by themselves and define the way it should be freed;
you do not need to worry about those. The only function that lets
you specify how to free the pixel data is
gdk_pixbuf_new_from_data(). Since you pass it a pre-allocated
pixel buffer, you must also specify a way to free that data. This
is done with a function of type #GdkPixbufDestroyNotify. When a
pixbuf created with gdk_pixbuf_new_from_data() is finalized, your
destroy notification function will be called, and it is its
responsibility to free the pixel array.
</para>
<para>
As an extension to traditional reference counting, #GdkPixbuf
structures support defining a handler for the last unref
operation. If gdk_pixbuf_unref() is called on a #GdkPixbuf
structure that has a reference count of 1, i.e. its last
reference, then the pixbuf's last unref handler function will be
called. It is up to this function to determine whether to
finalize the pixbuf using gdk_pixbuf_finalize() or to just
continue execution. This can be used to implement a pixbuf cache
efficiently; please see the programmer's documentation for
details.
</para>
<!-- FIXME: link the last sentence above to the relevant section of
the programmer's docs.
-->
<!-- ##### SECTION See_Also ##### -->
<para>
#GdkPixbuf, gdk_pixbuf_new_from_data().
</para>
<!-- ##### USER_FUNCTION GdkPixbufDestroyNotify ##### -->
<para>
A function of this type is responsible for freeing the pixel array
of a pixbuf. The gdk_pixbuf_new_from_data() 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 #GdkPixbufDestroyNotify so that the pixel data can be freed
when the pixbuf is finalized.
</para>
@pixels: The pixel array of the pixbuf that is being finalized.
@data: User closure data.
<!-- ##### FUNCTION gdk_pixbuf_ref ##### -->
<para>
</para>
@pixbuf:
@Returns:
<!-- ##### FUNCTION gdk_pixbuf_unref ##### -->
<para>
</para>
@pixbuf:
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