gstreamer/docs/gst/tmpl/gstobject.sgml

<!-- ##### SECTION Title ##### -->
GstObject

<!-- ##### SECTION Short_Description ##### -->
Base class for the GStreamer object hierarchy

<!-- ##### SECTION Long_Description ##### -->
<para>
GstObject provides a root for the object hierarchy tree filed in by the
GST library.  It is currently a thin wrapper on top of
<classname>GObject</classname>. It is an abstract class that is not
very usable on its own.
</para>

<para>
GstObject gives us basic refcounting, parenting functionality and locking.
Most of the function are just extended for special GStreamer needs and can be
found under the same name in the base class of GstObject which is GObject
(e.g. g_object_ref becomes gst_object_ref).
</para>

<para>
The most interesting difference between GstObject and GObject is the "floating"
reference count. A GObject is created with a reference count of 1, owned by the
creator of the GObject. (The owner of a reference is the code section that has
the right to call gst_object_unref() in order to remove that reference.)
A GstObject is created with a reference count of 1 also, but it isn't owned by
anyone; calling gst_object_unref() on the newly-created GtkObject is incorrect.
Instead, the initial reference count of a GstObject is "floating". The floating
reference can be removed by anyone at any time, by calling gst_object_sink().
gst_object_sink() does nothing if an object is already sunk (has no floating
reference).
</para>
<para>
When you add a GstElement to its parent container, the parent container will do
this:
<programlisting>
  gst_object_ref (GST_OBJECT (child_element));
  gst_object_sink (GST_OBJECT (child_element));
</programlisting>
This means that the container now owns a reference to the child element (since
it called gst_object_ref()), and the child element has no floating reference.
</para>
<para>
The purpose of the floating reference is to keep the child element alive until
you add it to a parent container:
<programlisting>
   element = gst_element_factory_make (factoryname, name);
   /* element has one floating reference to keep it alive */
   gtk_bin_add (GTK_BIN (bin), element);
   /* element has one non-floating reference owned by the container */
</programlisting>
</para>
<para>
Another effect of this is, that calling gst_object_unref() on a bin object, will
also destoy all the GstElement objects in it. The same is true for calling
gst_bin_remove().
</para>

<para>
gst_object_set_name() and gst_object_get_name() are used to set/get the name of the 
object.
</para>

<!-- ##### SECTION See_Also ##### -->
<para>

</para>

<!-- ##### STRUCT GstObject ##### -->
<para>

</para>


<!-- ##### SIGNAL GstObject::deep-notify ##### -->
<para>
The deep notify signal is used to be notified of property changes.
it is typically attached to the toplevel bin to receive notifications
from all the elements contained in that bin.
</para>

@gstobject: the object which received the signal.
@arg1: the object that originated the signal
@arg2: the property that changed

<!-- ##### SIGNAL GstObject::object-saved ##### -->
<para>
Is trigered whenever a new object is saved to XML. You can connect to
this signal to insert custom XML tags into the core XML.
</para>

@gstobject: the object which received the signal.
@arg1: the xmlNodePtr of the parent node

<!-- ##### SIGNAL GstObject::parent-set ##### -->
<para>
Is emitted when the parent of an object is set.
</para>

@gstobject: the object which received the signal.
@arg1: the new parent

<!-- ##### SIGNAL GstObject::parent-unset ##### -->
<para>
Is emitted when the parent of an object is unset.
</para>

@gstobject: the object which received the signal.
@arg1: the old parent

<!-- ##### ARG GstObject:name ##### -->
<para>
The name of the object
</para>

<!-- ##### ENUM GstObjectFlags ##### -->
<para>
Flags for an object
</para>

@GST_DESTROYED: The object is flagged for destruction
@GST_FLOATING: The object is created but has no parent yet to manage it
@GST_OBJECT_FLAG_LAST: subclasses can add additional flags starting from this flag

<!-- ##### MACRO GST_FLAGS ##### -->
<para>
This macro returns the entire set of flags for the object.
</para>

@obj: Object to return flags for.


<!-- ##### MACRO GST_FLAG_IS_SET ##### -->
<para>
This macro checks to see if the given flag is set.
</para>

@obj: GstSrc to check for flag in.
@flag: Flag to check for, must be a single bit in guint32.


<!-- ##### MACRO GST_FLAG_SET ##### -->
<para>
This macro sets the given bits.
</para>

@obj: Object to set flag in.
@flag: Flag to set, can by any number of bits in guint32.


<!-- ##### MACRO GST_FLAG_UNSET ##### -->
<para>
This macro usets the given bits.
</para>

@obj: Object to unset flag in.
@flag: Flag to set, must be a single bit in guint32.


<!-- ##### MACRO GST_OBJECT_NAME ##### -->
<para>
Get the name of this object
</para>

@obj: Object to get the name of.


<!-- ##### MACRO GST_OBJECT_PARENT ##### -->
<para>
Get the parent of this object
</para>

@obj: Object to get the parent of.


<!-- ##### MACRO GST_OBJECT_DESTROYED ##### -->
<para>
Check if the object has been destroyed.
</para>

@obj: The Object to check


<!-- ##### MACRO GST_OBJECT_FLOATING ##### -->
<para>
Check if the object is floating.
</para>

@obj: The Object to check


<!-- ##### MACRO GST_LOCK ##### -->
<para>
This macro will obtain a lock on the object, making serialization
possible.
</para>

@obj: Object to lock.


<!-- ##### MACRO GST_TRYLOCK ##### -->
<para>
This macro will try to obtain a lock on the object, but will return with
FALSE if it can't get it immediately.
</para>

@obj: Object to try to get a lock on.


<!-- ##### MACRO GST_UNLOCK ##### -->
<para>
This macro releases a lock on the object.
</para>

@obj: Object to unlock.


<!-- ##### MACRO GST_GET_LOCK ##### -->
<para>
Acquire a reference to the mutex of this object.
</para>

@obj: Object to get the mutex of.


<!-- ##### FUNCTION gst_object_set_name ##### -->
<para>

</para>

@object: 
@name: 


<!-- ##### FUNCTION gst_object_get_name ##### -->
<para>

</para>

@object: 
@Returns: 


<!-- ##### FUNCTION gst_object_set_parent ##### -->
<para>

</para>

@object: 
@parent: 


<!-- ##### FUNCTION gst_object_get_parent ##### -->
<para>

</para>

@object: 
@Returns: 


<!-- ##### FUNCTION gst_object_unparent ##### -->
<para>

</para>

@object: 


<!-- ##### FUNCTION gst_object_default_deep_notify ##### -->
<para>

</para>

@object: 
@orig: 
@pspec: 
@excluded_props: 


<!-- ##### FUNCTION gst_object_check_uniqueness ##### -->
<para>

</para>

@list: 
@name: 
@Returns: 


<!-- ##### FUNCTION gst_object_save_thyself ##### -->
<para>

</para>

@object: 
@parent: 
@Returns: 


<!-- ##### FUNCTION gst_object_restore_thyself ##### -->
<para>

</para>

@object: 
@self: 


<!-- ##### FUNCTION gst_object_ref ##### -->
<para>

</para>

@object: the object
@Returns: 


<!-- ##### FUNCTION gst_object_unref ##### -->
<para>

</para>

@object: the object


<!-- ##### FUNCTION gst_object_sink ##### -->
<para>

</para>

@object: the object


<!-- ##### FUNCTION gst_object_replace ##### -->
<para>

</para>

@oldobj: 
@newobj: 


<!-- ##### FUNCTION gst_object_get_path_string ##### -->
<para>

</para>

@object: 
@Returns: 


<!-- ##### FUNCTION gst_class_signal_connect ##### -->
<para>

</para>

@klass: 
@name: 
@func: 
@func_data: 
@Returns: 


<!-- ##### FUNCTION gst_class_signal_emit_by_name ##### -->
<para>

</para>

@object: 
@name: 
@self: