GDK-PixBuf Reference Manual: Reference Counting and Memory Mangement

## Reference Counting and Memory Mangement Reference Counting and Memory Mangement — Functions for reference counting and memory management on pixbufs. |

## Functions

GdkPixbuf * | gdk_pixbuf_ref ()
void | gdk_pixbuf_unref ()
void | (*GdkPixbufDestroyNotify) ()

## Object Hierarchy

## Includes

    #include <gdk-pixbuf/gdk-pixbuf.h>

## Description

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 by calling `g_object_ref()`. When it no longer needs the pixbuf, it should subtract a reference by calling `g_object_unref()`. The pixbuf will be destroyed when its reference count drops to zero. Newly-created GdkPixbuf structures start with a reference count of one.

> As GdkPixbuf is derived from GObject now, `gdk_pixbuf_ref()` and > `gdk_pixbuf_unref()` are deprecated in favour of `g_object_ref()` > and `g_object_unref()` resp.

Finalizing 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.

## Functions

### gdk_pixbuf_ref ()

    GdkPixbuf *
    gdk_pixbuf_ref (GdkPixbuf *pixbuf);

`gdk_pixbuf_ref` has been deprecated since version 2.0 and should not be used in newly-written code.

Use `g_object_ref()`.

Adds a reference to a pixbuf.

#### Parameters

pixbuf | A pixbuf. |

#### Returns

The same as the `pixbuf` argument.

### gdk_pixbuf_unref ()

    void
    gdk_pixbuf_unref (GdkPixbuf *pixbuf);

`gdk_pixbuf_unref` has been deprecated since version 2.0 and should not be used in newly-written code.

Use `g_object_unref()`.

Removes a reference from a pixbuf.

#### Parameters

pixbuf | A pixbuf. |

### GdkPixbufDestroyNotify ()

    void
    (*GdkPixbufDestroyNotify) (guchar *pixels,
                               gpointer data);

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.

#### Parameters

pixels | The pixel array of the pixbuf that is being finalized. | [array][element-type guint8]
data | User closure data. | [closure]

## Types and Values

## See Also

GdkPixbuf, `gdk_pixbuf_new_from_data()`.