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| <div class="refentry"> |
| <a name="GstBus"></a><div class="titlepage"></div> |
| <div class="refnamediv"><table width="100%"><tr> |
| <td valign="top"> |
| <h2><span class="refentrytitle"><a name="GstBus.top_of_page"></a>GstBus</span></h2> |
| <p>GstBus — Asynchronous message bus subsystem</p> |
| </td> |
| <td class="gallery_image" valign="top" align="right"></td> |
| </tr></table></div> |
| <div class="refsect1"> |
| <a name="GstBus.functions"></a><h2>Functions</h2> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="functions_return"> |
| <col class="functions_name"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="function_type"> |
| <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> |
| </td> |
| <td class="function_name"> |
| <span class="c_punctuation">(</span><a class="link" href="GstBus.html#GstBusFunc" title="GstBusFunc ()">*GstBusFunc</a><span class="c_punctuation">)</span> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a class="link" href="GstBus.html#GstBusSyncReply" title="enum GstBusSyncReply"><span class="returnvalue">GstBusSyncReply</span></a> |
| </td> |
| <td class="function_name"> |
| <span class="c_punctuation">(</span><a class="link" href="GstBus.html#GstBusSyncHandler" title="GstBusSyncHandler ()">*GstBusSyncHandler</a><span class="c_punctuation">)</span> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a class="link" href="GstBus.html" title="GstBus"><span class="returnvalue">GstBus</span></a> * |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-new" title="gst_bus_new ()">gst_bus_new</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-post" title="gst_bus_post ()">gst_bus_post</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-have-pending" title="gst_bus_have_pending ()">gst_bus_have_pending</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-peek" title="gst_bus_peek ()">gst_bus_peek</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-pop" title="gst_bus_pop ()">gst_bus_pop</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-pop-filtered" title="gst_bus_pop_filtered ()">gst_bus_pop_filtered</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-timed-pop" title="gst_bus_timed_pop ()">gst_bus_timed_pop</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-timed-pop-filtered" title="gst_bus_timed_pop_filtered ()">gst_bus_timed_pop_filtered</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <span class="returnvalue">void</span> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-set-flushing" title="gst_bus_set_flushing ()">gst_bus_set_flushing</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <span class="returnvalue">void</span> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-set-sync-handler" title="gst_bus_set_sync_handler ()">gst_bus_set_sync_handler</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a class="link" href="GstBus.html#GstBusSyncReply" title="enum GstBusSyncReply"><span class="returnvalue">GstBusSyncReply</span></a> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-sync-signal-handler" title="gst_bus_sync_signal_handler ()">gst_bus_sync_signal_handler</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#GSource"><span class="returnvalue">GSource</span></a> * |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-create-watch" title="gst_bus_create_watch ()">gst_bus_create_watch</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#guint"><span class="returnvalue">guint</span></a> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-add-watch-full" title="gst_bus_add_watch_full ()">gst_bus_add_watch_full</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#guint"><span class="returnvalue">guint</span></a> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-add-watch" title="gst_bus_add_watch ()">gst_bus_add_watch</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-remove-watch" title="gst_bus_remove_watch ()">gst_bus_remove_watch</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <span class="returnvalue">void</span> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-disable-sync-message-emission" title="gst_bus_disable_sync_message_emission ()">gst_bus_disable_sync_message_emission</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <span class="returnvalue">void</span> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-enable-sync-message-emission" title="gst_bus_enable_sync_message_emission ()">gst_bus_enable_sync_message_emission</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-async-signal-func" title="gst_bus_async_signal_func ()">gst_bus_async_signal_func</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <span class="returnvalue">void</span> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-add-signal-watch" title="gst_bus_add_signal_watch ()">gst_bus_add_signal_watch</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <span class="returnvalue">void</span> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-add-signal-watch-full" title="gst_bus_add_signal_watch_full ()">gst_bus_add_signal_watch_full</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <span class="returnvalue">void</span> |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-remove-signal-watch" title="gst_bus_remove_signal_watch ()">gst_bus_remove_signal_watch</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| <tr> |
| <td class="function_type"> |
| <a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| </td> |
| <td class="function_name"> |
| <a class="link" href="GstBus.html#gst-bus-poll" title="gst_bus_poll ()">gst_bus_poll</a> <span class="c_punctuation">()</span> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect1"> |
| <a name="GstBus.properties"></a><h2>Properties</h2> |
| <div class="informaltable"><table border="0"> |
| <colgroup> |
| <col width="150px" class="properties_type"> |
| <col width="300px" class="properties_name"> |
| <col width="200px" class="properties_flags"> |
| </colgroup> |
| <tbody><tr> |
| <td class="property_type"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></td> |
| <td class="property_name"><a class="link" href="GstBus.html#GstBus--enable-async" title="The “enable-async” property">enable-async</a></td> |
| <td class="property_flags">Write / Construct Only</td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <div class="refsect1"> |
| <a name="GstBus.signals"></a><h2>Signals</h2> |
| <div class="informaltable"><table border="0"> |
| <colgroup> |
| <col width="150px" class="signals_return"> |
| <col width="300px" class="signals_name"> |
| <col width="200px" class="signals_flags"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="signal_type"><span class="returnvalue">void</span></td> |
| <td class="signal_name"><a class="link" href="GstBus.html#GstBus-message" title="The “message” signal">message</a></td> |
| <td class="signal_flags"><a href="https://developer.gnome.org/gobject/unstable/gobject-Signals.html#G-SIGNAL-DETAILED:CAPS">Has Details</a></td> |
| </tr> |
| <tr> |
| <td class="signal_type"><span class="returnvalue">void</span></td> |
| <td class="signal_name"><a class="link" href="GstBus.html#GstBus-sync-message" title="The “sync-message” signal">sync-message</a></td> |
| <td class="signal_flags"><a href="https://developer.gnome.org/gobject/unstable/gobject-Signals.html#G-SIGNAL-DETAILED:CAPS">Has Details</a></td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect1"> |
| <a name="GstBus.other"></a><h2>Types and Values</h2> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="name"> |
| <col class="description"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="datatype_keyword">struct</td> |
| <td class="function_name"><a class="link" href="GstBus.html#GstBus-struct" title="struct GstBus">GstBus</a></td> |
| </tr> |
| <tr> |
| <td class="datatype_keyword">enum</td> |
| <td class="function_name"><a class="link" href="GstBus.html#GstBusFlags" title="enum GstBusFlags">GstBusFlags</a></td> |
| </tr> |
| <tr> |
| <td class="datatype_keyword">enum</td> |
| <td class="function_name"><a class="link" href="GstBus.html#GstBusSyncReply" title="enum GstBusSyncReply">GstBusSyncReply</a></td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect1"> |
| <a name="GstBus.object-hierarchy"></a><h2>Object Hierarchy</h2> |
| <pre class="screen"> <a href="https://developer.gnome.org/gobject/unstable/gobject-The-Base-Object-Type.html#GObject">GObject</a> |
| <span class="lineart">╰──</span> <a href="https://developer.gnome.org/gobject/unstable/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a> |
| <span class="lineart">╰──</span> <a class="link" href="GstObject.html" title="GstObject">GstObject</a> |
| <span class="lineart">╰──</span> GstBus |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="GstBus.includes"></a><h2>Includes</h2> |
| <pre class="synopsis">#include <gst/gst.h> |
| </pre> |
| </div> |
| <div class="refsect1"> |
| <a name="GstBus.description"></a><h2>Description</h2> |
| <p>The <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> is an object responsible for delivering <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> packets in |
| a first-in first-out way from the streaming threads (see <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a>) to the |
| application.</p> |
| <p>Since the application typically only wants to deal with delivery of these |
| messages from one thread, the GstBus will marshall the messages between |
| different threads. This is important since the actual streaming of media |
| is done in another thread than the application.</p> |
| <p>The GstBus provides support for <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#GSource"><span class="type">GSource</span></a> based notifications. This makes it |
| possible to handle the delivery in the glib mainloop.</p> |
| <p>The <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#GSource"><span class="type">GSource</span></a> callback function <a class="link" href="GstBus.html#gst-bus-async-signal-func" title="gst_bus_async_signal_func ()"><code class="function">gst_bus_async_signal_func()</code></a> can be used to |
| convert all bus messages into signal emissions.</p> |
| <p>A message is posted on the bus with the <a class="link" href="GstBus.html#gst-bus-post" title="gst_bus_post ()"><code class="function">gst_bus_post()</code></a> method. With the |
| <a class="link" href="GstBus.html#gst-bus-peek" title="gst_bus_peek ()"><code class="function">gst_bus_peek()</code></a> and <a class="link" href="GstBus.html#gst-bus-pop" title="gst_bus_pop ()"><code class="function">gst_bus_pop()</code></a> methods one can look at or retrieve a |
| previously posted message.</p> |
| <p>The bus can be polled with the <a class="link" href="GstBus.html#gst-bus-poll" title="gst_bus_poll ()"><code class="function">gst_bus_poll()</code></a> method. This methods blocks |
| up to the specified timeout value until one of the specified messages types |
| is posted on the bus. The application can then <a class="link" href="GstBus.html#gst-bus-pop" title="gst_bus_pop ()"><code class="function">gst_bus_pop()</code></a> the messages |
| from the bus to handle them. |
| Alternatively the application can register an asynchronous bus function |
| using <a class="link" href="GstBus.html#gst-bus-add-watch-full" title="gst_bus_add_watch_full ()"><code class="function">gst_bus_add_watch_full()</code></a> or <a class="link" href="GstBus.html#gst-bus-add-watch" title="gst_bus_add_watch ()"><code class="function">gst_bus_add_watch()</code></a>. This function will |
| install a <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#GSource"><span class="type">GSource</span></a> in the default glib main loop and will deliver messages |
| a short while after they have been posted. Note that the main loop should |
| be running for the asynchronous callbacks.</p> |
| <p>It is also possible to get messages from the bus without any thread |
| marshalling with the <a class="link" href="GstBus.html#gst-bus-set-sync-handler" title="gst_bus_set_sync_handler ()"><code class="function">gst_bus_set_sync_handler()</code></a> method. This makes it |
| possible to react to a message in the same thread that posted the |
| message on the bus. This should only be used if the application is able |
| to deal with messages from different threads.</p> |
| <p>Every <a class="link" href="GstPipeline.html" title="GstPipeline"><span class="type">GstPipeline</span></a> has one bus.</p> |
| <p>Note that a <a class="link" href="GstPipeline.html" title="GstPipeline"><span class="type">GstPipeline</span></a> will set its bus into flushing state when changing |
| from READY to NULL state.</p> |
| </div> |
| <div class="refsect1"> |
| <a name="GstBus.functions_details"></a><h2>Functions</h2> |
| <div class="refsect2"> |
| <a name="GstBusFunc"></a><h3>GstBusFunc ()</h3> |
| <pre class="programlisting"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> |
| <span class="c_punctuation">(</span>*GstBusFunc<span class="c_punctuation">)</span> (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> *message</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data</code></em>);</pre> |
| <p>Specifies the type of function passed to <a class="link" href="GstBus.html#gst-bus-add-watch" title="gst_bus_add_watch ()"><code class="function">gst_bus_add_watch()</code></a> or |
| <a class="link" href="GstBus.html#gst-bus-add-watch-full" title="gst_bus_add_watch_full ()"><code class="function">gst_bus_add_watch_full()</code></a>, which is called from the mainloop when a message |
| is available on the bus.</p> |
| <p>The message passed to the function will be unreffed after execution of this |
| function so it should not be freed in the function.</p> |
| <p>Note that this function is used as a GSourceFunc which means that returning |
| <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> will remove the GSource from the mainloop.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.2.7"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>the <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> that sent the message</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>message</p></td> |
| <td class="parameter_description"><p>the <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a></p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>user_data</p></td> |
| <td class="parameter_description"><p>user data that has been given, when registering the handler</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.2.8"></a><h4>Returns</h4> |
| <p> <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> if the event source should be removed.</p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="GstBusSyncHandler"></a><h3>GstBusSyncHandler ()</h3> |
| <pre class="programlisting"><a class="link" href="GstBus.html#GstBusSyncReply" title="enum GstBusSyncReply"><span class="returnvalue">GstBusSyncReply</span></a> |
| <span class="c_punctuation">(</span>*GstBusSyncHandler<span class="c_punctuation">)</span> (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> *message</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data</code></em>);</pre> |
| <p>Handler will be invoked synchronously, when a new message has been injected |
| into the bus. This function is mostly used internally. Only one sync handler |
| can be attached to a given bus.</p> |
| <p>If the handler returns GST_BUS_DROP, it should unref the message, else the |
| message should not be unreffed by the sync handler.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.3.6"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>the <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> that sent the message</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>message</p></td> |
| <td class="parameter_description"><p>the <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a></p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>user_data</p></td> |
| <td class="parameter_description"><p>user data that has been given, when registering the handler</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.3.7"></a><h4>Returns</h4> |
| <p> <a class="link" href="GstBus.html#GstBusSyncReply" title="enum GstBusSyncReply"><span class="type">GstBusSyncReply</span></a> stating what to do with the message</p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-new"></a><h3>gst_bus_new ()</h3> |
| <pre class="programlisting"><a class="link" href="GstBus.html" title="GstBus"><span class="returnvalue">GstBus</span></a> * |
| gst_bus_new (<em class="parameter"><code><span class="type">void</span></code></em>);</pre> |
| <p>Creates a new <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> instance.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.4.5"></a><h4>Returns</h4> |
| <p> a new <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> instance. </p> |
| <p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span></p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-post"></a><h3>gst_bus_post ()</h3> |
| <pre class="programlisting"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> |
| gst_bus_post (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> *message</code></em>);</pre> |
| <p>Post a message on the given bus. Ownership of the message |
| is taken by the bus.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.5.5"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> to post on</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>message</p></td> |
| <td class="parameter_description"><p> the <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> to post. </p></td> |
| <td class="parameter_annotations"><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span></td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.5.6"></a><h4>Returns</h4> |
| <p> <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the message could be posted, <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> if the bus is flushing.</p> |
| <p>MT safe.</p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-have-pending"></a><h3>gst_bus_have_pending ()</h3> |
| <pre class="programlisting"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> |
| gst_bus_have_pending (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>);</pre> |
| <p>Check if there are pending messages on the bus that |
| should be handled.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.6.5"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody><tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> to check</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.6.6"></a><h4>Returns</h4> |
| <p> <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if there are messages on the bus to be handled, <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> |
| otherwise.</p> |
| <p>MT safe.</p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-peek"></a><h3>gst_bus_peek ()</h3> |
| <pre class="programlisting"><a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| gst_bus_peek (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>);</pre> |
| <p>Peek the message on the top of the bus' queue. The message will remain |
| on the bus' message queue. A reference is returned, and needs to be unreffed |
| by the caller.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.7.5"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody><tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a></p></td> |
| <td class="parameter_annotations"> </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.7.6"></a><h4>Returns</h4> |
| <p> the <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> that is on the |
| bus, or <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if the bus is empty.</p> |
| <p>MT safe. </p> |
| <p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-pop"></a><h3>gst_bus_pop ()</h3> |
| <pre class="programlisting"><a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| gst_bus_pop (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>);</pre> |
| <p>Get a message from the bus.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.8.5"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody><tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> to pop</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.8.6"></a><h4>Returns</h4> |
| <p> the <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> that is on the |
| bus, or <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if the bus is empty. The message is taken from |
| the bus and needs to be unreffed with <a class="link" href="GstMessage.html#gst-message-unref" title="gst_message_unref ()"><code class="function">gst_message_unref()</code></a> after |
| usage.</p> |
| <p>MT safe. </p> |
| <p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-pop-filtered"></a><h3>gst_bus_pop_filtered ()</h3> |
| <pre class="programlisting"><a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| gst_bus_pop_filtered (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a class="link" href="GstMessage.html#GstMessageType" title="enum GstMessageType"><span class="type">GstMessageType</span></a> types</code></em>);</pre> |
| <p>Get a message matching <em class="parameter"><code>type</code></em> |
| from the bus. Will discard all messages on |
| the bus that do not match <em class="parameter"><code>type</code></em> |
| and that have been posted before the first |
| message that does match <em class="parameter"><code>type</code></em> |
| . If there is no message matching <em class="parameter"><code>type</code></em> |
| on |
| the bus, all messages will be discarded. It is not possible to use message |
| enums beyond <a class="link" href="GstMessage.html#GST-MESSAGE-EXTENDED:CAPS"><span class="type">GST_MESSAGE_EXTENDED</span></a> in the <em class="parameter"><code>events</code></em> |
| mask.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.9.5"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> to pop</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>types</p></td> |
| <td class="parameter_description"><p>message types to take into account</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.9.6"></a><h4>Returns</h4> |
| <p> the next <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> matching |
| <em class="parameter"><code>type</code></em> |
| that is on the bus, or <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if the bus is empty or there |
| is no message matching <em class="parameter"><code>type</code></em> |
| . The message is taken from the bus |
| and needs to be unreffed with <a class="link" href="GstMessage.html#gst-message-unref" title="gst_message_unref ()"><code class="function">gst_message_unref()</code></a> after usage.</p> |
| <p>MT safe. </p> |
| <p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-timed-pop"></a><h3>gst_bus_timed_pop ()</h3> |
| <pre class="programlisting"><a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| gst_bus_timed_pop (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timeout</code></em>);</pre> |
| <p>Get a message from the bus, waiting up to the specified timeout.</p> |
| <p>If <em class="parameter"><code>timeout</code></em> |
| is 0, this function behaves like <a class="link" href="GstBus.html#gst-bus-pop" title="gst_bus_pop ()"><code class="function">gst_bus_pop()</code></a>. If <em class="parameter"><code>timeout</code></em> |
| is |
| <a class="link" href="GstClock.html#GST-CLOCK-TIME-NONE:CAPS" title="GST_CLOCK_TIME_NONE"><span class="type">GST_CLOCK_TIME_NONE</span></a>, this function will block forever until a message was |
| posted on the bus.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.10.6"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> to pop</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>timeout</p></td> |
| <td class="parameter_description"><p>a timeout</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.10.7"></a><h4>Returns</h4> |
| <p> the <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> that is on the |
| bus after the specified timeout or <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if the bus is empty |
| after the timeout expired. The message is taken from the bus |
| and needs to be unreffed with <a class="link" href="GstMessage.html#gst-message-unref" title="gst_message_unref ()"><code class="function">gst_message_unref()</code></a> after usage.</p> |
| <p>MT safe. </p> |
| <p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-timed-pop-filtered"></a><h3>gst_bus_timed_pop_filtered ()</h3> |
| <pre class="programlisting"><a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| gst_bus_timed_pop_filtered (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timeout</code></em>, |
| <em class="parameter"><code><a class="link" href="GstMessage.html#GstMessageType" title="enum GstMessageType"><span class="type">GstMessageType</span></a> types</code></em>);</pre> |
| <p>Get a message from the bus whose type matches the message type mask <em class="parameter"><code>types</code></em> |
| , |
| waiting up to the specified timeout (and discarding any messages that do not |
| match the mask provided).</p> |
| <p>If <em class="parameter"><code>timeout</code></em> |
| is 0, this function behaves like <a class="link" href="GstBus.html#gst-bus-pop-filtered" title="gst_bus_pop_filtered ()"><code class="function">gst_bus_pop_filtered()</code></a>. If |
| <em class="parameter"><code>timeout</code></em> |
| is <a class="link" href="GstClock.html#GST-CLOCK-TIME-NONE:CAPS" title="GST_CLOCK_TIME_NONE"><span class="type">GST_CLOCK_TIME_NONE</span></a>, this function will block forever until a |
| matching message was posted on the bus.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.11.6"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> to pop from</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>timeout</p></td> |
| <td class="parameter_description"><p>a timeout in nanoseconds, or GST_CLOCK_TIME_NONE to wait forever</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>types</p></td> |
| <td class="parameter_description"><p>message types to take into account, GST_MESSAGE_ANY for any type</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.11.7"></a><h4>Returns</h4> |
| <p> a <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> matching the |
| filter in <em class="parameter"><code>types</code></em> |
| , or <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if no matching message was found on |
| the bus until the timeout expired. The message is taken from |
| the bus and needs to be unreffed with <a class="link" href="GstMessage.html#gst-message-unref" title="gst_message_unref ()"><code class="function">gst_message_unref()</code></a> after |
| usage.</p> |
| <p>MT safe. </p> |
| <p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-set-flushing"></a><h3>gst_bus_set_flushing ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> |
| gst_bus_set_flushing (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> flushing</code></em>);</pre> |
| <p>If <em class="parameter"><code>flushing</code></em> |
| , flush out and unref any messages queued in the bus. Releases |
| references to the message origin objects. Will flush future messages until |
| <a class="link" href="GstBus.html#gst-bus-set-flushing" title="gst_bus_set_flushing ()"><code class="function">gst_bus_set_flushing()</code></a> sets <em class="parameter"><code>flushing</code></em> |
| to <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a>.</p> |
| <p>MT safe.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.12.6"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a></p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>flushing</p></td> |
| <td class="parameter_description"><p>whether or not to flush the bus</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-set-sync-handler"></a><h3>gst_bus_set_sync_handler ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> |
| gst_bus_set_sync_handler (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a class="link" href="GstBus.html#GstBusSyncHandler" title="GstBusSyncHandler ()"><span class="type">GstBusSyncHandler</span></a> func</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Datasets.html#GDestroyNotify"><span class="type">GDestroyNotify</span></a> notify</code></em>);</pre> |
| <p>Sets the synchronous handler on the bus. The function will be called |
| every time a new message is posted on the bus. Note that the function |
| will be called in the same thread context as the posting object. This |
| function is usually only called by the creator of the bus. Applications |
| should handle messages asynchronously using the gst_bus watch and poll |
| functions.</p> |
| <p>You cannot replace an existing sync_handler. You can pass <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> to this |
| function, which will clear the existing handler.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.13.6"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> to install the handler on</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>func</p></td> |
| <td class="parameter_description"><p> The handler function to install. </p></td> |
| <td class="parameter_annotations"><span class="annotation">[<acronym title="NULL is OK, both for passing and for returning."><span class="acronym">allow-none</span></acronym>]</span></td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>user_data</p></td> |
| <td class="parameter_description"><p>User data that will be sent to the handler function.</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>notify</p></td> |
| <td class="parameter_description"><p>called when <em class="parameter"><code>user_data</code></em> |
| becomes unused</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-sync-signal-handler"></a><h3>gst_bus_sync_signal_handler ()</h3> |
| <pre class="programlisting"><a class="link" href="GstBus.html#GstBusSyncReply" title="enum GstBusSyncReply"><span class="returnvalue">GstBusSyncReply</span></a> |
| gst_bus_sync_signal_handler (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> *message</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> data</code></em>);</pre> |
| <p>A helper GstBusSyncHandler that can be used to convert all synchronous |
| messages into signals.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.14.5"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a></p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>message</p></td> |
| <td class="parameter_description"><p>the <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> received</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>data</p></td> |
| <td class="parameter_description"><p>user data</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.14.6"></a><h4>Returns</h4> |
| <p> GST_BUS_PASS</p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-create-watch"></a><h3>gst_bus_create_watch ()</h3> |
| <pre class="programlisting"><a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#GSource"><span class="returnvalue">GSource</span></a> * |
| gst_bus_create_watch (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>);</pre> |
| <p>Create watch for this bus. The GSource will be dispatched whenever |
| a message is on the bus. After the GSource is dispatched, the |
| message is popped off the bus and unreffed.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.15.5"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody><tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> to create the watch for</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.15.6"></a><h4>Returns</h4> |
| <p> a <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#GSource"><span class="type">GSource</span></a> that can be added to a mainloop. </p> |
| <p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>]</span></p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-add-watch-full"></a><h3>gst_bus_add_watch_full ()</h3> |
| <pre class="programlisting"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#guint"><span class="returnvalue">guint</span></a> |
| gst_bus_add_watch_full (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a> priority</code></em>, |
| <em class="parameter"><code><a class="link" href="GstBus.html#GstBusFunc" title="GstBusFunc ()"><span class="type">GstBusFunc</span></a> func</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Datasets.html#GDestroyNotify"><span class="type">GDestroyNotify</span></a> notify</code></em>);</pre> |
| <p>Adds a bus watch to the default main context with the given <em class="parameter"><code>priority</code></em> |
| (e.g. |
| <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#G-PRIORITY-DEFAULT:CAPS"><code class="literal">G_PRIORITY_DEFAULT</code></a>). It is also possible to use a non-default main |
| context set up using <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#g-main-context-push-thread-default"><code class="function">g_main_context_push_thread_default()</code></a> (before |
| one had to create a bus watch source and attach it to the desired main |
| context 'manually').</p> |
| <p>This function is used to receive asynchronous messages in the main loop. |
| There can only be a single bus watch per bus, you must remove it before you |
| can set a new one.</p> |
| <p>When <em class="parameter"><code>func</code></em> |
| is called, the message belongs to the caller; if you want to |
| keep a copy of it, call <a class="link" href="GstMessage.html#gst-message-ref" title="gst_message_ref ()"><code class="function">gst_message_ref()</code></a> before leaving <em class="parameter"><code>func</code></em> |
| .</p> |
| <p>The watch can be removed using <a class="link" href="GstBus.html#gst-bus-remove-watch" title="gst_bus_remove_watch ()"><code class="function">gst_bus_remove_watch()</code></a> or by returning <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> |
| from <em class="parameter"><code>func</code></em> |
| . If the watch was added to the default main context it is also |
| possible to remove the watch using <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#g-source-remove"><code class="function">g_source_remove()</code></a>.</p> |
| <p>MT safe.</p> |
| <p><span class="annotation">[<acronym title="Rename the original symbol's name to SYMBOL."><span class="acronym">rename-to</span></acronym> gst_bus_add_watch]</span></p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.16.10"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> to create the watch for.</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>priority</p></td> |
| <td class="parameter_description"><p>The priority of the watch.</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>func</p></td> |
| <td class="parameter_description"><p>A function to call when a message is received.</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>user_data</p></td> |
| <td class="parameter_description"><p>user data passed to <em class="parameter"><code>func</code></em> |
| .</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>notify</p></td> |
| <td class="parameter_description"><p>the function to call when the source is removed.</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.16.11"></a><h4>Returns</h4> |
| <p> The event source id or 0 if <em class="parameter"><code>bus</code></em> |
| already got an event source.</p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-add-watch"></a><h3>gst_bus_add_watch ()</h3> |
| <pre class="programlisting"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#guint"><span class="returnvalue">guint</span></a> |
| gst_bus_add_watch (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a class="link" href="GstBus.html#GstBusFunc" title="GstBusFunc ()"><span class="type">GstBusFunc</span></a> func</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data</code></em>);</pre> |
| <p>Adds a bus watch to the default main context with the default priority |
| (<a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#G-PRIORITY-DEFAULT:CAPS"><code class="literal">G_PRIORITY_DEFAULT</code></a>). It is also possible to use a non-default main |
| context set up using <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#g-main-context-push-thread-default"><code class="function">g_main_context_push_thread_default()</code></a> (before |
| one had to create a bus watch source and attach it to the desired main |
| context 'manually').</p> |
| <p>This function is used to receive asynchronous messages in the main loop. |
| There can only be a single bus watch per bus, you must remove it before you |
| can set a new one.</p> |
| <p>The watch can be removed using <a class="link" href="GstBus.html#gst-bus-remove-watch" title="gst_bus_remove_watch ()"><code class="function">gst_bus_remove_watch()</code></a> or by returning <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> |
| from <em class="parameter"><code>func</code></em> |
| . If the watch was added to the default main context it is also |
| possible to remove the watch using <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#g-source-remove"><code class="function">g_source_remove()</code></a>.</p> |
| <p><span class="annotation">[<acronym title="Exposed in C code, not necessarily available in other languages."><span class="acronym">skip</span></acronym>]</span></p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.17.8"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> to create the watch for</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>func</p></td> |
| <td class="parameter_description"><p>A function to call when a message is received.</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>user_data</p></td> |
| <td class="parameter_description"><p>user data passed to <em class="parameter"><code>func</code></em> |
| .</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.17.9"></a><h4>Returns</h4> |
| <p> The event source id or 0 if <em class="parameter"><code>bus</code></em> |
| already got an event source.</p> |
| <p>MT safe.</p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-remove-watch"></a><h3>gst_bus_remove_watch ()</h3> |
| <pre class="programlisting"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> |
| gst_bus_remove_watch (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>);</pre> |
| <p>Removes an installed bus watch from <em class="parameter"><code>bus</code></em> |
| .</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.18.5"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody><tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> to remove the watch from.</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.18.6"></a><h4>Returns</h4> |
| <p> <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> on success or <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> if <em class="parameter"><code>bus</code></em> |
| has no event source.</p> |
| </div> |
| <p class="since">Since: <a class="link" href="ix03.html#api-index-1.6">1.6</a></p> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-disable-sync-message-emission"></a><h3>gst_bus_disable_sync_message_emission ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> |
| gst_bus_disable_sync_message_emission (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>);</pre> |
| <p>Instructs GStreamer to stop emitting the "sync-message" signal for this bus. |
| See <a class="link" href="GstBus.html#gst-bus-enable-sync-message-emission" title="gst_bus_enable_sync_message_emission ()"><code class="function">gst_bus_enable_sync_message_emission()</code></a> for more information.</p> |
| <p>In the event that multiple pieces of code have called |
| <a class="link" href="GstBus.html#gst-bus-enable-sync-message-emission" title="gst_bus_enable_sync_message_emission ()"><code class="function">gst_bus_enable_sync_message_emission()</code></a>, the sync-message emissions will only |
| be stopped after all calls to <a class="link" href="GstBus.html#gst-bus-enable-sync-message-emission" title="gst_bus_enable_sync_message_emission ()"><code class="function">gst_bus_enable_sync_message_emission()</code></a> were |
| "cancelled" by calling this function. In this way the semantics are exactly |
| the same as <a class="link" href="GstObject.html#gst-object-ref" title="gst_object_ref ()"><code class="function">gst_object_ref()</code></a> that which calls enable should also call |
| disable.</p> |
| <p>MT safe.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.19.7"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody><tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> on which you previously called |
| <a class="link" href="GstBus.html#gst-bus-enable-sync-message-emission" title="gst_bus_enable_sync_message_emission ()"><code class="function">gst_bus_enable_sync_message_emission()</code></a></p></td> |
| <td class="parameter_annotations"> </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-enable-sync-message-emission"></a><h3>gst_bus_enable_sync_message_emission ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> |
| gst_bus_enable_sync_message_emission (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>);</pre> |
| <p>Instructs GStreamer to emit the "sync-message" signal after running the bus's |
| sync handler. This function is here so that code can ensure that they can |
| synchronously receive messages without having to affect what the bin's sync |
| handler is.</p> |
| <p>This function may be called multiple times. To clean up, the caller is |
| responsible for calling <a class="link" href="GstBus.html#gst-bus-disable-sync-message-emission" title="gst_bus_disable_sync_message_emission ()"><code class="function">gst_bus_disable_sync_message_emission()</code></a> as many times |
| as this function is called.</p> |
| <p>While this function looks similar to <a class="link" href="GstBus.html#gst-bus-add-signal-watch" title="gst_bus_add_signal_watch ()"><code class="function">gst_bus_add_signal_watch()</code></a>, it is not |
| exactly the same -- this function enables <span class="emphasis"><em>synchronous</em></span> emission of |
| signals when messages arrive; <a class="link" href="GstBus.html#gst-bus-add-signal-watch" title="gst_bus_add_signal_watch ()"><code class="function">gst_bus_add_signal_watch()</code></a> adds an idle callback |
| to pop messages off the bus <span class="emphasis"><em>asynchronously</em></span>. The sync-message signal |
| comes from the thread of whatever object posted the message; the "message" |
| signal is marshalled to the main thread via the main loop.</p> |
| <p>MT safe.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.20.8"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody><tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> on which you want to receive the "sync-message" signal</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-async-signal-func"></a><h3>gst_bus_async_signal_func ()</h3> |
| <pre class="programlisting"><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> |
| gst_bus_async_signal_func (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> *message</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> data</code></em>);</pre> |
| <p>A helper <a class="link" href="GstBus.html#GstBusFunc" title="GstBusFunc ()"><span class="type">GstBusFunc</span></a> that can be used to convert all asynchronous messages |
| into signals.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.21.5"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a></p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>message</p></td> |
| <td class="parameter_description"><p>the <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> received</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>data</p></td> |
| <td class="parameter_description"><p>user data</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.21.6"></a><h4>Returns</h4> |
| <p> <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a></p> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-add-signal-watch"></a><h3>gst_bus_add_signal_watch ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> |
| gst_bus_add_signal_watch (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>);</pre> |
| <p>Adds a bus signal watch to the default main context with the default priority |
| (<a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#G-PRIORITY-DEFAULT:CAPS"><code class="literal">G_PRIORITY_DEFAULT</code></a>). It is also possible to use a non-default |
| main context set up using <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#g-main-context-push-thread-default"><code class="function">g_main_context_push_thread_default()</code></a> (before |
| one had to create a bus watch source and attach it to the desired main |
| context 'manually').</p> |
| <p>After calling this statement, the bus will emit the "message" signal for each |
| message posted on the bus.</p> |
| <p>This function may be called multiple times. To clean up, the caller is |
| responsible for calling <a class="link" href="GstBus.html#gst-bus-remove-signal-watch" title="gst_bus_remove_signal_watch ()"><code class="function">gst_bus_remove_signal_watch()</code></a> as many times as this |
| function is called.</p> |
| <p>MT safe.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.22.8"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody><tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> on which you want to receive the "message" signal</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-add-signal-watch-full"></a><h3>gst_bus_add_signal_watch_full ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> |
| gst_bus_add_signal_watch_full (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gint"><span class="type">gint</span></a> priority</code></em>);</pre> |
| <p>Adds a bus signal watch to the default main context with the given <em class="parameter"><code>priority</code></em> |
| |
| (e.g. <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#G-PRIORITY-DEFAULT:CAPS"><code class="literal">G_PRIORITY_DEFAULT</code></a>). It is also possible to use a non-default main |
| context set up using <a href="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html#g-main-context-push-thread-default"><code class="function">g_main_context_push_thread_default()</code></a> |
| (before one had to create a bus watch source and attach it to the desired |
| main context 'manually').</p> |
| <p>After calling this statement, the bus will emit the "message" signal for each |
| message posted on the bus when the main loop is running.</p> |
| <p>This function may be called multiple times. To clean up, the caller is |
| responsible for calling <a class="link" href="GstBus.html#gst-bus-remove-signal-watch" title="gst_bus_remove_signal_watch ()"><code class="function">gst_bus_remove_signal_watch()</code></a> as many times as this |
| function is called.</p> |
| <p>There can only be a single bus watch per bus, you must remove any signal |
| watch before you can set another type of watch.</p> |
| <p>MT safe.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.23.9"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> on which you want to receive the "message" signal</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>priority</p></td> |
| <td class="parameter_description"><p>The priority of the watch.</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-remove-signal-watch"></a><h3>gst_bus_remove_signal_watch ()</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> |
| gst_bus_remove_signal_watch (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>);</pre> |
| <p>Removes a signal watch previously added with <a class="link" href="GstBus.html#gst-bus-add-signal-watch" title="gst_bus_add_signal_watch ()"><code class="function">gst_bus_add_signal_watch()</code></a>.</p> |
| <p>MT safe.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.24.6"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody><tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> you previously added a signal watch to</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="gst-bus-poll"></a><h3>gst_bus_poll ()</h3> |
| <pre class="programlisting"><a class="link" href="GstMessage.html" title="GstMessage"><span class="returnvalue">GstMessage</span></a> * |
| gst_bus_poll (<em class="parameter"><code><a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus</code></em>, |
| <em class="parameter"><code><a class="link" href="GstMessage.html#GstMessageType" title="enum GstMessageType"><span class="type">GstMessageType</span></a> events</code></em>, |
| <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timeout</code></em>);</pre> |
| <p>Poll the bus for messages. Will block while waiting for messages to come. |
| You can specify a maximum time to poll with the <em class="parameter"><code>timeout</code></em> |
| parameter. If |
| <em class="parameter"><code>timeout</code></em> |
| is negative, this function will block indefinitely.</p> |
| <p>All messages not in <em class="parameter"><code>events</code></em> |
| will be popped off the bus and will be ignored. |
| It is not possible to use message enums beyond <a class="link" href="GstMessage.html#GST-MESSAGE-EXTENDED:CAPS"><span class="type">GST_MESSAGE_EXTENDED</span></a> in the |
| <em class="parameter"><code>events</code></em> |
| mask</p> |
| <p>Because poll is implemented using the "message" signal enabled by |
| <a class="link" href="GstBus.html#gst-bus-add-signal-watch" title="gst_bus_add_signal_watch ()"><code class="function">gst_bus_add_signal_watch()</code></a>, calling <a class="link" href="GstBus.html#gst-bus-poll" title="gst_bus_poll ()"><code class="function">gst_bus_poll()</code></a> will cause the "message" |
| signal to be emitted for every message that poll sees. Thus a "message" |
| signal handler will see the same messages that this function sees -- neither |
| will steal messages from the other.</p> |
| <p>This function will run a main loop from the default main context when |
| polling.</p> |
| <p>You should never use this function, since it is pure evil. This is |
| especially true for GUI applications based on Gtk+ or Qt, but also for any |
| other non-trivial application that uses the GLib main loop. As this function |
| runs a GLib main loop, any callback attached to the default GLib main |
| context may be invoked. This could be timeouts, GUI events, I/O events etc.; |
| even if <a class="link" href="GstBus.html#gst-bus-poll" title="gst_bus_poll ()"><code class="function">gst_bus_poll()</code></a> is called with a 0 timeout. Any of these callbacks |
| may do things you do not expect, e.g. destroy the main application window or |
| some other resource; change other application state; display a dialog and |
| run another main loop until the user clicks it away. In short, using this |
| function may add a lot of complexity to your code through unexpected |
| re-entrancy and unexpected changes to your application's state.</p> |
| <p>For 0 timeouts use <a class="link" href="GstBus.html#gst-bus-pop-filtered" title="gst_bus_pop_filtered ()"><code class="function">gst_bus_pop_filtered()</code></a> instead of this function; for |
| other short timeouts use <a class="link" href="GstBus.html#gst-bus-timed-pop-filtered" title="gst_bus_timed_pop_filtered ()"><code class="function">gst_bus_timed_pop_filtered()</code></a>; everything else is |
| better handled by setting up an asynchronous bus watch and doing things |
| from there.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.25.10"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>a <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a></p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>events</p></td> |
| <td class="parameter_description"><p>a mask of <a class="link" href="GstMessage.html#GstMessageType" title="enum GstMessageType"><span class="type">GstMessageType</span></a>, representing the set of message types to |
| poll for (note special handling of extended message types below)</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>timeout</p></td> |
| <td class="parameter_description"><p>the poll timeout, as a <a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a>, or <a class="link" href="GstClock.html#GST-CLOCK-TIME-NONE:CAPS" title="GST_CLOCK_TIME_NONE"><span class="type">GST_CLOCK_TIME_NONE</span></a> to poll |
| indefinitely.</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <div class="refsect3"> |
| <a name="id-1.3.10.10.25.11"></a><h4>Returns</h4> |
| <p> the message that was received, |
| or <a href="https://developer.gnome.org/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if the poll timed out. The message is taken from the |
| bus and needs to be unreffed with <a class="link" href="GstMessage.html#gst-message-unref" title="gst_message_unref ()"><code class="function">gst_message_unref()</code></a> after |
| usage. </p> |
| <p><span class="annotation">[<acronym title="Free data after the code is done."><span class="acronym">transfer full</span></acronym>][<acronym title="NULL may be passed as the value in, out, in-out; or as a return value."><span class="acronym">nullable</span></acronym>]</span></p> |
| </div> |
| </div> |
| </div> |
| <div class="refsect1"> |
| <a name="GstBus.other_details"></a><h2>Types and Values</h2> |
| <div class="refsect2"> |
| <a name="GstBus-struct"></a><h3>struct GstBus</h3> |
| <pre class="programlisting">struct GstBus;</pre> |
| <p>The opaque <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> data structure.</p> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="GstBusFlags"></a><h3>enum GstBusFlags</h3> |
| <p>The standard flags that a bus may have.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.11.3.4"></a><h4>Members</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="300px" class="enum_members_name"> |
| <col class="enum_members_description"> |
| <col width="200px" class="enum_members_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="enum_member_name"><p><a name="GST-BUS-FLUSHING:CAPS"></a>GST_BUS_FLUSHING</p></td> |
| <td class="enum_member_description"> |
| <p>The bus is currently dropping all messages</p> |
| </td> |
| <td class="enum_member_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="enum_member_name"><p><a name="GST-BUS-FLAG-LAST:CAPS"></a>GST_BUS_FLAG_LAST</p></td> |
| <td class="enum_member_description"> |
| <p>offset to define more flags</p> |
| </td> |
| <td class="enum_member_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="GstBusSyncReply"></a><h3>enum GstBusSyncReply</h3> |
| <p>The result values for a GstBusSyncHandler.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.11.4.4"></a><h4>Members</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="300px" class="enum_members_name"> |
| <col class="enum_members_description"> |
| <col width="200px" class="enum_members_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="enum_member_name"><p><a name="GST-BUS-DROP:CAPS"></a>GST_BUS_DROP</p></td> |
| <td class="enum_member_description"> |
| <p>drop the message</p> |
| </td> |
| <td class="enum_member_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="enum_member_name"><p><a name="GST-BUS-PASS:CAPS"></a>GST_BUS_PASS</p></td> |
| <td class="enum_member_description"> |
| <p>pass the message to the async queue</p> |
| </td> |
| <td class="enum_member_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="enum_member_name"><p><a name="GST-BUS-ASYNC:CAPS"></a>GST_BUS_ASYNC</p></td> |
| <td class="enum_member_description"> |
| <p>pass message to async queue, continue if message is handled</p> |
| </td> |
| <td class="enum_member_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| </div> |
| </div> |
| <div class="refsect1"> |
| <a name="GstBus.property-details"></a><h2>Property Details</h2> |
| <div class="refsect2"> |
| <a name="GstBus--enable-async"></a><h3>The <code class="literal">“enable-async”</code> property</h3> |
| <pre class="programlisting"> “enable-async” <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a></pre> |
| <p>Enable async message delivery for bus watches and gst_bus_pop().</p> |
| <p>Flags: Write / Construct Only</p> |
| <p>Default value: TRUE</p> |
| </div> |
| </div> |
| <div class="refsect1"> |
| <a name="GstBus.signal-details"></a><h2>Signal Details</h2> |
| <div class="refsect2"> |
| <a name="GstBus-message"></a><h3>The <code class="literal">“message”</code> signal</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> |
| user_function (<a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus, |
| <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> *message, |
| <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data)</pre> |
| <p>A message has been posted on the bus. This signal is emitted from a |
| GSource added to the mainloop. this signal will only be emitted when |
| there is a mainloop running.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.13.2.5"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>the object which received the signal</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>message</p></td> |
| <td class="parameter_description"><p>the message that has been posted asynchronously</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>user_data</p></td> |
| <td class="parameter_description"><p>user data set when the signal handler was connected.</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <p>Flags: <a href="https://developer.gnome.org/gobject/unstable/gobject-Signals.html#G-SIGNAL-DETAILED:CAPS">Has Details</a></p> |
| </div> |
| <hr> |
| <div class="refsect2"> |
| <a name="GstBus-sync-message"></a><h3>The <code class="literal">“sync-message”</code> signal</h3> |
| <pre class="programlisting"><span class="returnvalue">void</span> |
| user_function (<a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> *bus, |
| <a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a> *message, |
| <a href="https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data)</pre> |
| <p>A message has been posted on the bus. This signal is emitted from the |
| thread that posted the message so one has to be careful with locking.</p> |
| <p>This signal will not be emitted by default, you have to call |
| <a class="link" href="GstBus.html#gst-bus-enable-sync-message-emission" title="gst_bus_enable_sync_message_emission ()"><code class="function">gst_bus_enable_sync_message_emission()</code></a> before.</p> |
| <div class="refsect3"> |
| <a name="id-1.3.10.13.3.6"></a><h4>Parameters</h4> |
| <div class="informaltable"><table width="100%" border="0"> |
| <colgroup> |
| <col width="150px" class="parameters_name"> |
| <col class="parameters_description"> |
| <col width="200px" class="parameters_annotations"> |
| </colgroup> |
| <tbody> |
| <tr> |
| <td class="parameter_name"><p>bus</p></td> |
| <td class="parameter_description"><p>the object which received the signal</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>message</p></td> |
| <td class="parameter_description"><p>the message that has been posted synchronously</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| <tr> |
| <td class="parameter_name"><p>user_data</p></td> |
| <td class="parameter_description"><p>user data set when the signal handler was connected.</p></td> |
| <td class="parameter_annotations"> </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <p>Flags: <a href="https://developer.gnome.org/gobject/unstable/gobject-Signals.html#G-SIGNAL-DETAILED:CAPS">Has Details</a></p> |
| </div> |
| </div> |
| <div class="refsect1"> |
| <a name="GstBus.see-also"></a><h2>See Also</h2> |
| <p><a class="link" href="GstMessage.html" title="GstMessage"><span class="type">GstMessage</span></a>, <a class="link" href="GstElement.html" title="GstElement"><span class="type">GstElement</span></a></p> |
| </div> |
| </div> |
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