## GstGhostPad

GstGhostPad — Pseudo link pads

## Synopsis

    #include <gst/gst.h>

                        GstGhostPad;
    GstPad*             gst_ghost_pad_new                   (const gchar *name,
                                                             GstPad *target);
    GstPad*             gst_ghost_pad_new_no_target         (const gchar *name,
                                                             GstPadDirection dir);
    GstPad*             gst_ghost_pad_new_from_template     (const gchar *name,
                                                             GstPad *target,
                                                             GstPadTemplate *templ);
    GstPad*             gst_ghost_pad_new_no_target_from_template
                                                            (const gchar *name,
                                                             GstPadTemplate *templ);
    gboolean            gst_ghost_pad_set_target            (GstGhostPad *gpad,
                                                             GstPad *newtarget);
    GstPad*             gst_ghost_pad_get_target            (GstGhostPad *gpad);
    gboolean            gst_ghost_pad_construct             (GstGhostPad *gpad);

## Object Hierarchy

      GObject
       +----GstObject
             +----GstPad
                   +----GstProxyPad
                         +----GstGhostPad

## Description

GhostPads are useful when organizing pipelines with GstBin like elements. The idea here is to create hierarchical element graphs. The bin element contains a sub-graph. Now one would like to treat the bin-element like any other GstElement. This is where GhostPads come into play. A GhostPad acts as a proxy for another pad. Thus the bin can have sink and source ghost-pads that are associated with sink and source pads of the child elements.

If the target pad is known at creation time, `gst_ghost_pad_new()` is the function to use to get a ghost-pad. Otherwise one can use `gst_ghost_pad_new_no_target()` to create the ghost-pad and use `gst_ghost_pad_set_target()` to establish the association later on.

Note that GhostPads add overhead to the data processing of a pipeline.

Last reviewed on 2005-11-18 (0.9.5)

## Details

### GstGhostPad

    typedef struct _GstGhostPad GstGhostPad;

Opaque GstGhostPad structure.

### gst_ghost_pad_new ()

    GstPad*             gst_ghost_pad_new                   (const gchar *name,
                                                             GstPad *target);

Create a new ghostpad with `target` as the target. The direction will be taken from the target pad. `target` must be unlinked.

Will ref the target.

`name` : | the name of the new pad, or NULL to assign a default name.
`target` : | the pad to ghost.
Returns : | a new GstPad, or NULL in case of an error.

### gst_ghost_pad_new_no_target ()

    GstPad*             gst_ghost_pad_new_no_target         (const gchar *name,
                                                             GstPadDirection dir);

Create a new ghostpad without a target with the given direction. A target can be set on the ghostpad later with the `gst_ghost_pad_set_target()` function.

The created ghostpad will not have a padtemplate.

`name` : | the name of the new pad, or NULL to assign a default name.
`dir` : | the direction of the ghostpad
Returns : | a new GstPad, or NULL in case of an error.

### gst_ghost_pad_new_from_template ()

    GstPad*             gst_ghost_pad_new_from_template     (const gchar *name,
                                                             GstPad *target,
                                                             GstPadTemplate *templ);

Create a new ghostpad with `target` as the target. The direction will be taken from the target pad. The template used on the ghostpad will be `template`.

Will ref the target.

`name` : | the name of the new pad, or NULL to assign a default name.
`target` : | the pad to ghost.
`templ` : | the GstPadTemplate to use on the ghostpad.
Returns : | a new GstPad, or NULL in case of an error.

Since 0.10.10

### gst_ghost_pad_new_no_target_from_template ()

    GstPad*             gst_ghost_pad_new_no_target_from_template
                                                            (const gchar *name,
                                                             GstPadTemplate *templ);

Create a new ghostpad based on `templ`, without setting a target. The direction will be taken from the `templ`.

`name` : | the name of the new pad, or NULL to assign a default name.
`templ` : | the GstPadTemplate to create the ghostpad from.
Returns : | a new GstPad, or NULL in case of an error.

Since 0.10.10

### gst_ghost_pad_set_target ()

    gboolean            gst_ghost_pad_set_target            (GstGhostPad *gpad,
                                                             GstPad *newtarget);

Set the new target of the ghostpad `gpad`. Any existing target is unlinked and links to the new target are established. if `newtarget` is NULL the target will be cleared.

`gpad` : | the GstGhostPad
`newtarget` : | the new pad target
Returns : | TRUE if the new target could be set. This function can return FALSE when the internal pads could not be linked.

### gst_ghost_pad_get_target ()

    GstPad*             gst_ghost_pad_get_target            (GstGhostPad *gpad);

Get the target pad of `gpad`. Unref target pad after usage.

`gpad` : | the GstGhostPad
Returns : | the target GstPad, can be NULL if the ghostpad has no target set. Unref target pad after usage.

### gst_ghost_pad_construct ()

    gboolean            gst_ghost_pad_construct             (GstGhostPad *gpad);

Finish initialization of a newly allocated ghost pad.

This function is most useful in language bindings and when subclassing GstGhostPad; plugin and application developers normally will not call this function. Call this function directly after a call to g_object_new (GST_TYPE_GHOST_PAD, "direction", `dir`, ..., NULL).

`gpad` : | the newly allocated ghost pad
Returns : | `TRUE` if the construction succeeds, `FALSE` otherwise.

Since 0.10.22

## See Also

GstPad