|  |  |  | GStreamer 0.10 Core Reference Manual |  | 
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#include <gst/gst.h> GQuark gst_plugin_error_quark (void); #define GST_PLUGIN_ERROR enum GstPluginError; GstPlugin; GstPluginDesc; gboolean (*GstPluginInitFunc) (GstPlugin *plugin); #define GST_PLUGIN_DEFINE (major,minor,name,description,init,version,license,package,origin) #define GST_PLUGIN_DEFINE_STATIC (major,minor,name,description,init,version,license,package,origin) #define GST_LICENSE_UNKNOWN gboolean (*GstPluginFilter) (GstPlugin *plugin, gpointer user_data); const gchar* gst_plugin_get_name (GstPlugin *plugin); const gchar* gst_plugin_get_description (GstPlugin *plugin); const gchar* gst_plugin_get_filename (GstPlugin *plugin); const gchar* gst_plugin_get_license (GstPlugin *plugin); const gchar* gst_plugin_get_package (GstPlugin *plugin); const gchar* gst_plugin_get_origin (GstPlugin *plugin); const gchar* gst_plugin_get_source (GstPlugin *plugin); const gchar* gst_plugin_get_version (GstPlugin *plugin); GModule* gst_plugin_get_module (GstPlugin *plugin); gboolean gst_plugin_is_loaded (GstPlugin *plugin); gboolean gst_plugin_name_filter (GstPlugin *plugin, const gchar *name); GstPlugin* gst_plugin_load_file (const gchar *filename, GError **error); GstPlugin* gst_plugin_load (GstPlugin *plugin); GstPlugin* gst_plugin_load_by_name (const gchar *name); void gst_plugin_list_free (GList *list);
GStreamer is extensible, so GstElement instances can be loaded at runtime. A plugin system can provide one or more of the basic GStreamer GstPluginFeature subclasses.
A plugin should export a symbol gst_plugin_desc that is a struct of type GstPluginDesc. the plugin loader will check the version of the core library the plugin was linked against and will create a new GstPlugin. It will then call the GstPluginInitFunc function that was provided in the gst_plugin_desc.
Once you have a handle to a GstPlugin (e.g. from the GstRegistryPool), you can add any object that subclasses GstPluginFeature.
Use gst_plugin_find_feature() and gst_plugin_get_feature_list() to find
features in a plugin.
Usually plugins are always automaticlly loaded so you don't need to call
gst_plugin_load() explicitly to bring it into memory. There are options to
statically link plugins to an app or even use GStreamer without a plugin
repository in which case gst_plugin_load() can be needed to bring the plugin
into memory.
GQuark gst_plugin_error_quark (void);
Get the error quark.
| Returns : | The error quark used in GError messages | 
#define GST_PLUGIN_ERROR gst_plugin_error_quark ()
The error message category quark
typedef enum
{
  GST_PLUGIN_ERROR_MODULE,
  GST_PLUGIN_ERROR_DEPENDENCIES,
  GST_PLUGIN_ERROR_NAME_MISMATCH
} GstPluginError;
The plugin loading errors
typedef struct {
  gint major_version;
  gint minor_version;
  const gchar *name;
  gchar *description;
  GstPluginInitFunc plugin_init;
  const gchar *version;
  const gchar *license;
  const gchar *source;
  const gchar *package;
  const gchar *origin;
  gpointer _gst_reserved[GST_PADDING];
} GstPluginDesc;
A plugin should export a variable of this type called plugin_desc. The plugin loader will use the data provided there to initialize the plugin.
The licence parameter must be one of: LGPL, GPL, QPL, GPL/QPL, MPL,
BSD, MIT/X11, Proprietary, unknown.
| gint major_version; | the major version number of core that plugin was compiled for | 
| gint minor_version; | the minor version number of core that plugin was compiled for | 
| const gchar * name; | a unique name of the plugin | 
| gchar * description; | description of plugin | 
| GstPluginInitFunc plugin_init; | pointer to the init function of this plugin. | 
| const gchar * version; | version of the plugin | 
| const gchar * license; | effective license of plugin | 
| const gchar * source; | source module plugin belongs to | 
| const gchar * package; | shipped package plugin belongs to | 
| const gchar * origin; | URL to provider of plugin | 
| gpointer _gst_reserved[GST_PADDING]; | private, for later expansion | 
gboolean (*GstPluginInitFunc) (GstPlugin *plugin);
A plugin should provide a pointer to a function of this type in the plugin_desc struct. This function will be called by the loader at startup.
| plugin: | The plugin object that can be used to register GstPluginFeatures for this plugin. | 
| Returns : | TRUEif plugin initialised successfully | 
#define GST_PLUGIN_DEFINE(major,minor,name,description,init,version,license,package,origin)
This macro needs to be used to define the entry point and meta data of a plugin. One would use this macro to export a plugin, so that it can be used by other applications
| major: | major version number of the gstreamer-core that plugin was compiled for | 
| minor: | minor version number of the gstreamer-core that plugin was compiled for | 
| name: | short, but unique name of the plugin | 
| description: | information about the purpose of the plugin | 
| init: | function pointer to the plugin_init method with the signature of static gboolean plugin_init (GstPlugin * plugin). | 
| version: | full version string (e.g. VERSION from config.h) | 
| license: | under which licence the package has been released, e.g. GPL, LGPL. | 
| package: | the package-name (e.g. PACKAGE_NAME from config.h) | 
| origin: | a description from where the package comes from (e.g. the homepage URL) | 
#define GST_PLUGIN_DEFINE_STATIC(major,minor,name,description,init,version,license,package,origin)
This macro needs to be used to define the entry point and meta data of a local plugin. One would use this macro to define a local plugin that can only be used by the own application.
| major: | major version number of the gstreamer-core that plugin was compiled for | 
| minor: | minor version number of the gstreamer-core that plugin was compiled for | 
| name: | short, but unique name of the plugin | 
| description: | information about the purpose of the plugin | 
| init: | function pointer to the plugin_init method with the signature of static gboolean plugin_init (GstPlugin * plugin). | 
| version: | full version string (e.g. VERSION from config.h) | 
| license: | under which licence the package has been released, e.g. GPL, LGPL. | 
| package: | the package-name (e.g. PACKAGE_NAME from config.h) | 
| origin: | a description from where the package comes from (e.g. the homepage URL) | 
#define GST_LICENSE_UNKNOWN "unknown"
To be used in GST_PLUGIN_DEFINE or GST_PLUGIN_DEFINE_STATIC if usure about the licence.
gboolean (*GstPluginFilter) (GstPlugin *plugin, gpointer user_data);
A function that can be used with e.g. gst_registry_plugin_filter()
to get a list of plugins that match certain criteria.
| plugin: | the plugin to check | 
| user_data: | the user_data that has been passed on e.g. gst_registry_plugin_filter() | 
| Returns : | TRUE for a positive match, FALSE otherwise | 
const gchar* gst_plugin_get_name (GstPlugin *plugin);
Get the short name of the plugin
| plugin: | plugin to get the name of | 
| Returns : | the name of the plugin | 
const gchar* gst_plugin_get_description (GstPlugin *plugin);
Get the long descriptive name of the plugin
| plugin: | plugin to get long name of | 
| Returns : | the long name of the plugin | 
const gchar* gst_plugin_get_filename (GstPlugin *plugin);
get the filename of the plugin
| plugin: | plugin to get the filename of | 
| Returns : | the filename of the plugin | 
const gchar* gst_plugin_get_license (GstPlugin *plugin);
get the license of the plugin
| plugin: | plugin to get the license of | 
| Returns : | the license of the plugin | 
const gchar* gst_plugin_get_package (GstPlugin *plugin);
get the package the plugin belongs to.
| plugin: | plugin to get the package of | 
| Returns : | the package of the plugin | 
const gchar* gst_plugin_get_origin (GstPlugin *plugin);
get the URL where the plugin comes from
| plugin: | plugin to get the origin of | 
| Returns : | the origin of the plugin | 
const gchar* gst_plugin_get_source (GstPlugin *plugin);
get the source module the plugin belongs to.
| plugin: | plugin to get the source of | 
| Returns : | the source of the plugin | 
const gchar* gst_plugin_get_version (GstPlugin *plugin);
get the version of the plugin
| plugin: | plugin to get the version of | 
| Returns : | the version of the plugin | 
GModule* gst_plugin_get_module (GstPlugin *plugin);
Gets the GModule of the plugin. If the plugin isn't loaded yet, NULL is returned.
| plugin: | plugin to query | 
| Returns : | module belonging to the plugin or NULL if the plugin isn't loaded yet. | 
gboolean gst_plugin_is_loaded (GstPlugin *plugin);
queries if the plugin is loaded into memory
| plugin: | plugin to query | 
| Returns : | TRUE is loaded, FALSE otherwise | 
gboolean gst_plugin_name_filter (GstPlugin *plugin, const gchar *name);
A standard filter that returns TRUE when the plugin is of the given name.
| plugin: | the plugin to check | 
| name: | the name of the plugin | 
| Returns : | TRUE if the plugin is of the given name. | 
GstPlugin* gst_plugin_load_file (const gchar *filename, GError **error);
Loads the given plugin and refs it. Caller needs to unref after use.
| filename: | the plugin filename to load | 
| error: | pointer to a NULL-valued GError | 
| Returns : | a reference to the existing loaded GstPlugin, a reference to the newly-loaded GstPlugin, or NULL if an error occurred. | 
GstPlugin* gst_plugin_load (GstPlugin *plugin);
Loads plugin. Note that the *return value* is the loaded plugin; plugin is
untouched. The normal use pattern of this function goes like this:
GstPlugin *loaded_plugin; loaded_plugin = gst_plugin_load (plugin); // presumably, we're no longer interested in the potentially-unloaded plugin gst_object_unref (plugin); plugin = loaded_plugin;
| plugin: | plugin to load | 
| Returns : | A reference to a loaded plugin, or NULL on error. | 
GstPlugin* gst_plugin_load_by_name (const gchar *name);
Load the named plugin. Refs the plugin.
| name: | name of plugin to load | 
| Returns : | A reference to a loaded plugin, or NULL on error. | 
void gst_plugin_list_free (GList *list);
Unrefs each member of list, then frees the list.
| list: | list of GstPlugin |