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<a href="#GstTask.description" class="shortcut">Description</a>
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<a href="#GstTask.object-hierarchy" class="shortcut">Object Hierarchy</a>
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<a name="GstTask"></a><div class="titlepage"></div>
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<h2><span class="refentrytitle"><a name="GstTask.top_of_page"></a>GstTask</span></h2>
<p>GstTask — Abstraction of GStreamer streaming threads.</p>
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<td valign="top" align="right"></td>
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<div class="refsynopsisdiv">
<a name="GstTask.synopsis"></a><h2>Synopsis</h2>
<pre class="synopsis">
#include &lt;gst/gst.h&gt;
struct <a class="link" href="GstTask.html#GstTask-struct" title="struct GstTask">GstTask</a>;
<span class="returnvalue">void</span> (<a class="link" href="GstTask.html#GstTaskFunction" title="GstTaskFunction ()">*GstTaskFunction</a>) (<em class="parameter"><code><span class="type">void</span> *data</code></em>);
enum <a class="link" href="GstTask.html#GstTaskState" title="enum GstTaskState">GstTaskState</a>;
#define <a class="link" href="GstTask.html#GST-TASK-BROADCAST:CAPS" title="GST_TASK_BROADCAST()">GST_TASK_BROADCAST</a> (task)
#define <a class="link" href="GstTask.html#GST-TASK-GET-COND:CAPS" title="GST_TASK_GET_COND()">GST_TASK_GET_COND</a> (task)
#define <a class="link" href="GstTask.html#GST-TASK-GET-LOCK:CAPS" title="GST_TASK_GET_LOCK()">GST_TASK_GET_LOCK</a> (task)
#define <a class="link" href="GstTask.html#GST-TASK-SIGNAL:CAPS" title="GST_TASK_SIGNAL()">GST_TASK_SIGNAL</a> (task)
#define <a class="link" href="GstTask.html#GST-TASK-STATE:CAPS" title="GST_TASK_STATE()">GST_TASK_STATE</a> (task)
#define <a class="link" href="GstTask.html#GST-TASK-WAIT:CAPS" title="GST_TASK_WAIT()">GST_TASK_WAIT</a> (task)
<a class="link" href="GstTask.html" title="GstTask"><span class="returnvalue">GstTask</span></a> * <a class="link" href="GstTask.html#gst-task-new" title="gst_task_new ()">gst_task_new</a> (<em class="parameter"><code><a class="link" href="GstTask.html#GstTaskFunction" title="GstTaskFunction ()"><span class="type">GstTaskFunction</span></a> func</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> data</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GstTask.html#gst-task-set-lock" title="gst_task_set_lock ()">gst_task_set_lock</a> (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Threads.html#GRecMutex"><span class="type">GRecMutex</span></a> *mutex</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GstTask.html#gst-task-set-pool" title="gst_task_set_pool ()">gst_task_set_pool</a> (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>,
<em class="parameter"><code><a class="link" href="GstTaskPool.html" title="GstTaskPool"><span class="type">GstTaskPool</span></a> *pool</code></em>);
<a class="link" href="GstTaskPool.html" title="GstTaskPool"><span class="returnvalue">GstTaskPool</span></a> * <a class="link" href="GstTask.html#gst-task-get-pool" title="gst_task_get_pool ()">gst_task_get_pool</a> (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);
<a class="link" href="GstTask.html#GstTaskThreadCallbacks" title="GstTaskThreadCallbacks">GstTaskThreadCallbacks</a>;
<span class="returnvalue">void</span> <a class="link" href="GstTask.html#gst-task-set-thread-callbacks" title="gst_task_set_thread_callbacks ()">gst_task_set_thread_callbacks</a> (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>,
<em class="parameter"><code><a class="link" href="GstTask.html#GstTaskThreadCallbacks" title="GstTaskThreadCallbacks"><span class="type">GstTaskThreadCallbacks</span></a> *callbacks</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Datasets.html#GDestroyNotify"><span class="type">GDestroyNotify</span></a> notify</code></em>);
<a class="link" href="GstTask.html#GstTaskState" title="enum GstTaskState"><span class="returnvalue">GstTaskState</span></a> <a class="link" href="GstTask.html#gst-task-get-state" title="gst_task_get_state ()">gst_task_get_state</a> (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> <a class="link" href="GstTask.html#gst-task-set-state" title="gst_task_set_state ()">gst_task_set_state</a> (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>,
<em class="parameter"><code><a class="link" href="GstTask.html#GstTaskState" title="enum GstTaskState"><span class="type">GstTaskState</span></a> state</code></em>);
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> <a class="link" href="GstTask.html#gst-task-pause" title="gst_task_pause ()">gst_task_pause</a> (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> <a class="link" href="GstTask.html#gst-task-start" title="gst_task_start ()">gst_task_start</a> (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> <a class="link" href="GstTask.html#gst-task-stop" title="gst_task_stop ()">gst_task_stop</a> (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> <a class="link" href="GstTask.html#gst-task-join" title="gst_task_join ()">gst_task_join</a> (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);
<span class="returnvalue">void</span> <a class="link" href="GstTask.html#gst-task-cleanup-all" title="gst_task_cleanup_all ()">gst_task_cleanup_all</a> (<em class="parameter"><code><span class="type">void</span></code></em>);
</pre>
</div>
<div class="refsect1">
<a name="GstTask.object-hierarchy"></a><h2>Object Hierarchy</h2>
<pre class="synopsis">
<a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GObject">GObject</a>
+----<a href="http://library.gnome.org/devel/gobject/unstable/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a>
+----<a class="link" href="GstObject.html" title="GstObject">GstObject</a>
+----GstTask
</pre>
</div>
<div class="refsect1">
<a name="GstTask.description"></a><h2>Description</h2>
<p>
<a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> is used by <a class="link" href="GstElement.html" title="GstElement"><span class="type">GstElement</span></a> and <a class="link" href="GstPad.html" title="GstPad"><span class="type">GstPad</span></a> to provide the data passing
threads in a <a class="link" href="GstPipeline.html" title="GstPipeline"><span class="type">GstPipeline</span></a>.
</p>
<p>
A <a class="link" href="GstPad.html" title="GstPad"><span class="type">GstPad</span></a> will typically start a <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> to push or pull data to/from the
peer pads. Most source elements start a <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> to push data. In some cases
a demuxer element can start a <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> to pull data from a peer element. This
is typically done when the demuxer can perform random access on the upstream
peer element for improved performance.
</p>
<p>
Although convenience functions exist on <a class="link" href="GstPad.html" title="GstPad"><span class="type">GstPad</span></a> to start/pause/stop tasks, it
might sometimes be needed to create a <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> manually if it is not related to
a <a class="link" href="GstPad.html" title="GstPad"><span class="type">GstPad</span></a>.
</p>
<p>
Before the <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> can be run, it needs a <a href="http://library.gnome.org/devel/glib/unstable/glib-Deprecated-Thread-APIs.html#GStaticRecMutex"><span class="type">GStaticRecMutex</span></a> that can be set with
<a class="link" href="GstTask.html#gst-task-set-lock" title="gst_task_set_lock ()"><code class="function">gst_task_set_lock()</code></a>.
</p>
<p>
The task can be started, paused and stopped with <a class="link" href="GstTask.html#gst-task-start" title="gst_task_start ()"><code class="function">gst_task_start()</code></a>, <a class="link" href="GstTask.html#gst-task-pause" title="gst_task_pause ()"><code class="function">gst_task_pause()</code></a>
and <a class="link" href="GstTask.html#gst-task-stop" title="gst_task_stop ()"><code class="function">gst_task_stop()</code></a> respectively or with the <a class="link" href="GstTask.html#gst-task-set-state" title="gst_task_set_state ()"><code class="function">gst_task_set_state()</code></a> function.
</p>
<p>
A <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> will repeatedly call the <a class="link" href="GstTask.html#GstTaskFunction" title="GstTaskFunction ()"><span class="type">GstTaskFunction</span></a> with the user data
that was provided when creating the task with <a class="link" href="GstTask.html#gst-task-new" title="gst_task_new ()"><code class="function">gst_task_new()</code></a>. While calling
the function it will acquire the provided lock. The provided lock is released
when the task pauses or stops.
</p>
<p>
Stopping a task with <a class="link" href="GstTask.html#gst-task-stop" title="gst_task_stop ()"><code class="function">gst_task_stop()</code></a> will not immediately make sure the task is
not running anymore. Use <a class="link" href="GstTask.html#gst-task-join" title="gst_task_join ()"><code class="function">gst_task_join()</code></a> to make sure the task is completely
stopped and the thread is stopped.
</p>
<p>
After creating a <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a>, use <a class="link" href="GstObject.html#gst-object-unref" title="gst_object_unref ()"><code class="function">gst_object_unref()</code></a> to free its resources. This can
only be done when the task is not running anymore.
</p>
<p>
Task functions can send a <a class="link" href="gstreamer-GstMessage.html#GstMessage" title="struct GstMessage"><span class="type">GstMessage</span></a> to send out-of-band data to the
application. The application can receive messages from the <a class="link" href="GstBus.html" title="GstBus"><span class="type">GstBus</span></a> in its
mainloop.
</p>
<p>
For debugging purposes, the task will configure its object name as the thread
name on Linux. Please note that the object name should be configured before the
task is started; changing the object name after the task has been started, has
no effect on the thread name.
</p>
<p>
Last reviewed on 2012-03-29 (0.11.3)
</p>
</div>
<div class="refsect1">
<a name="GstTask.details"></a><h2>Details</h2>
<div class="refsect2">
<a name="GstTask-struct"></a><h3>struct GstTask</h3>
<pre class="programlisting">struct GstTask {
GstTaskState state;
GCond cond;
GRecMutex *lock;
GstTaskFunction func;
gpointer data;
gboolean running;
};
</pre>
<p>
The <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> object.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><a class="link" href="GstTask.html#GstTaskState" title="enum GstTaskState"><span class="type">GstTaskState</span></a> <em class="structfield"><code><a name="GstTask-struct.state"></a>state</code></em>;</span></p></td>
<td>the state of the task</td>
</tr>
<tr>
<td><p><span class="term"><a href="http://library.gnome.org/devel/glib/unstable/glib-Threads.html#GCond"><span class="type">GCond</span></a> <em class="structfield"><code><a name="GstTask-struct.cond"></a>cond</code></em>;</span></p></td>
<td>used to pause/resume the task</td>
</tr>
<tr>
<td><p><span class="term"><a href="http://library.gnome.org/devel/glib/unstable/glib-Threads.html#GRecMutex"><span class="type">GRecMutex</span></a> *<em class="structfield"><code><a name="GstTask-struct.lock"></a>lock</code></em>;</span></p></td>
<td>The lock taken when iterating the task function</td>
</tr>
<tr>
<td><p><span class="term"><a class="link" href="GstTask.html#GstTaskFunction" title="GstTaskFunction ()"><span class="type">GstTaskFunction</span></a> <em class="structfield"><code><a name="GstTask-struct.func"></a>func</code></em>;</span></p></td>
<td>the function executed by this task</td>
</tr>
<tr>
<td><p><span class="term"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> <em class="structfield"><code><a name="GstTask-struct.data"></a>data</code></em>;</span></p></td>
<td>data passed to the task function</td>
</tr>
<tr>
<td><p><span class="term"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> <em class="structfield"><code><a name="GstTask-struct.running"></a>running</code></em>;</span></p></td>
<td>a flag indicating that the task is running</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GstTaskFunction"></a><h3>GstTaskFunction ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> (*GstTaskFunction) (<em class="parameter"><code><span class="type">void</span> *data</code></em>);</pre>
<p>
A function that will repeatedly be called in the thread created by
a <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>data</code></em> :</span></p></td>
<td>user data passed to the function</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GstTaskState"></a><h3>enum GstTaskState</h3>
<pre class="programlisting">typedef enum {
GST_TASK_STARTED,
GST_TASK_STOPPED,
GST_TASK_PAUSED
} GstTaskState;
</pre>
<p>
The different states a task can be in
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><a name="GST-TASK-STARTED:CAPS"></a><span class="term"><code class="literal">GST_TASK_STARTED</code></span></p></td>
<td>the task is started and running
</td>
</tr>
<tr>
<td><p><a name="GST-TASK-STOPPED:CAPS"></a><span class="term"><code class="literal">GST_TASK_STOPPED</code></span></p></td>
<td>the task is stopped
</td>
</tr>
<tr>
<td><p><a name="GST-TASK-PAUSED:CAPS"></a><span class="term"><code class="literal">GST_TASK_PAUSED</code></span></p></td>
<td>the task is paused
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GST-TASK-BROADCAST:CAPS"></a><h3>GST_TASK_BROADCAST()</h3>
<pre class="programlisting">#define GST_TASK_BROADCAST(task) g_cond_broadcast(GST_TASK_GET_COND (task))
</pre>
<p>
Send a broadcast signal to all waiting task conds
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>Task to broadcast</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GST-TASK-GET-COND:CAPS"></a><h3>GST_TASK_GET_COND()</h3>
<pre class="programlisting">#define GST_TASK_GET_COND(task) (&amp;GST_TASK_CAST(task)-&gt;cond)
</pre>
<p>
Get access to the cond of the task.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>Task to get the cond of</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GST-TASK-GET-LOCK:CAPS"></a><h3>GST_TASK_GET_LOCK()</h3>
<pre class="programlisting">#define GST_TASK_GET_LOCK(task) (GST_TASK_CAST(task)-&gt;lock)
</pre>
<p>
Get access to the task lock.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>Task to get the lock of</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GST-TASK-SIGNAL:CAPS"></a><h3>GST_TASK_SIGNAL()</h3>
<pre class="programlisting">#define GST_TASK_SIGNAL(task) g_cond_signal(GST_TASK_GET_COND (task))
</pre>
<p>
Signal the task cond
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>Task to signal</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GST-TASK-STATE:CAPS"></a><h3>GST_TASK_STATE()</h3>
<pre class="programlisting">#define GST_TASK_STATE(task) (GST_TASK_CAST(task)-&gt;state)
</pre>
<p>
Get access to the state of the task.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>Task to get the state of</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="GST-TASK-WAIT:CAPS"></a><h3>GST_TASK_WAIT()</h3>
<pre class="programlisting">#define GST_TASK_WAIT(task) g_cond_wait(GST_TASK_GET_COND (task), GST_OBJECT_GET_LOCK (task))
</pre>
<p>
Wait for the task cond to be signalled
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>Task to wait for</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-task-new"></a><h3>gst_task_new ()</h3>
<pre class="programlisting"><a class="link" href="GstTask.html" title="GstTask"><span class="returnvalue">GstTask</span></a> * gst_task_new (<em class="parameter"><code><a class="link" href="GstTask.html#GstTaskFunction" title="GstTaskFunction ()"><span class="type">GstTaskFunction</span></a> func</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> data</code></em>);</pre>
<p>
Create a new Task that will repeatedly call the provided <em class="parameter"><code>func</code></em>
with <em class="parameter"><code>data</code></em> as a parameter. Typically the task will run in
a new thread.
</p>
<p>
The function cannot be changed after the task has been created. You
must create a new <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> to change the function.
</p>
<p>
This function will not yet create and start a thread. Use <a class="link" href="GstTask.html#gst-task-start" title="gst_task_start ()"><code class="function">gst_task_start()</code></a> or
<a class="link" href="GstTask.html#gst-task-pause" title="gst_task_pause ()"><code class="function">gst_task_pause()</code></a> to create and start the GThread.
</p>
<p>
Before the task can be used, a <a href="http://library.gnome.org/devel/glib/unstable/glib-Deprecated-Thread-APIs.html#GStaticRecMutex"><span class="type">GStaticRecMutex</span></a> must be configured using the
<a class="link" href="GstTask.html#gst-task-set-lock" title="gst_task_set_lock ()"><code class="function">gst_task_set_lock()</code></a> function. This lock will always be acquired while
<em class="parameter"><code>func</code></em> is called.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>func</code></em> :</span></p></td>
<td>The <a class="link" href="GstTask.html#GstTaskFunction" title="GstTaskFunction ()"><span class="type">GstTaskFunction</span></a> to use</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>data</code></em> :</span></p></td>
<td>User data to pass to <em class="parameter"><code>func</code></em>. <span class="annotation">[<acronym title="This parameter is a 'user_data', for callbacks; many bindings can pass NULL here."><span class="acronym">closure</span></acronym>]</span>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>A new <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a>.
MT safe. <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>
<hr>
<div class="refsect2">
<a name="gst-task-set-lock"></a><h3>gst_task_set_lock ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gst_task_set_lock (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Threads.html#GRecMutex"><span class="type">GRecMutex</span></a> *mutex</code></em>);</pre>
<p>
Set the mutex used by the task. The mutex will be acquired before
calling the <a class="link" href="GstTask.html#GstTaskFunction" title="GstTaskFunction ()"><span class="type">GstTaskFunction</span></a>.
</p>
<p>
This function has to be called before calling <a class="link" href="GstTask.html#gst-task-pause" title="gst_task_pause ()"><code class="function">gst_task_pause()</code></a> or
<a class="link" href="GstTask.html#gst-task-start" title="gst_task_start ()"><code class="function">gst_task_start()</code></a>.
</p>
<p>
MT safe.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>The <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> to use</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>mutex</code></em> :</span></p></td>
<td>The <a href="http://library.gnome.org/devel/glib/unstable/glib-Threads.html#GRecMutex"><span class="type">GRecMutex</span></a> to use</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-task-set-pool"></a><h3>gst_task_set_pool ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gst_task_set_pool (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>,
<em class="parameter"><code><a class="link" href="GstTaskPool.html" title="GstTaskPool"><span class="type">GstTaskPool</span></a> *pool</code></em>);</pre>
<p>
Set <em class="parameter"><code>pool</code></em> as the new GstTaskPool for <em class="parameter"><code>task</code></em>. Any new streaming threads that
will be created by <em class="parameter"><code>task</code></em> will now use <em class="parameter"><code>pool</code></em>.
</p>
<p>
MT safe.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>a <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>pool</code></em> :</span></p></td>
<td>a <a class="link" href="GstTaskPool.html" title="GstTaskPool"><span class="type">GstTaskPool</span></a>. <span class="annotation">[<acronym title="Don't free data after the code is done."><span class="acronym">transfer none</span></acronym>]</span>
</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 0.10.24</p>
</div>
<hr>
<div class="refsect2">
<a name="gst-task-get-pool"></a><h3>gst_task_get_pool ()</h3>
<pre class="programlisting"><a class="link" href="GstTaskPool.html" title="GstTaskPool"><span class="returnvalue">GstTaskPool</span></a> * gst_task_get_pool (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);</pre>
<p>
Get the <a class="link" href="GstTaskPool.html" title="GstTaskPool"><span class="type">GstTaskPool</span></a> that this task will use for its streaming
threads.
</p>
<p>
MT safe.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>a <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>the <a class="link" href="GstTaskPool.html" title="GstTaskPool"><span class="type">GstTaskPool</span></a> used by <em class="parameter"><code>task</code></em>. <a class="link" href="GstObject.html#gst-object-unref" title="gst_object_unref ()"><code class="function">gst_object_unref()</code></a>
after usage. <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>
<p class="since">Since 0.10.24</p>
</div>
<hr>
<div class="refsect2">
<a name="GstTaskThreadCallbacks"></a><h3>GstTaskThreadCallbacks</h3>
<pre class="programlisting">typedef struct {
/* manage the lifetime of the thread */
void (*enter_thread) (GstTask *task, GThread *thread, gpointer user_data);
void (*leave_thread) (GstTask *task, GThread *thread, gpointer user_data);
} GstTaskThreadCallbacks;
</pre>
<p>
Custom GstTask thread callback functions that can be installed.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstTaskThreadCallbacks.enter-thread"></a>enter_thread</code></em> ()</span></p></td>
<td>a thread is entered, this callback is called when the new
thread enters its function.</td>
</tr>
<tr>
<td><p><span class="term"><em class="structfield"><code><a name="GstTaskThreadCallbacks.leave-thread"></a>leave_thread</code></em> ()</span></p></td>
<td>a thread is exiting, this is called when the thread is about
to leave its function</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 0.10.24</p>
</div>
<hr>
<div class="refsect2">
<a name="gst-task-set-thread-callbacks"></a><h3>gst_task_set_thread_callbacks ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gst_task_set_thread_callbacks (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>,
<em class="parameter"><code><a class="link" href="GstTask.html#GstTaskThreadCallbacks" title="GstTaskThreadCallbacks"><span class="type">GstTaskThreadCallbacks</span></a> *callbacks</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Datasets.html#GDestroyNotify"><span class="type">GDestroyNotify</span></a> notify</code></em>);</pre>
<p>
Set callbacks which will be executed when a new thread is needed, the thread
function is entered and left and when the thread is joined.
</p>
<p>
By default a thread for <em class="parameter"><code>task</code></em> will be created from a default thread pool.
</p>
<p>
Objects can use custom GThreads or can perform additional configuration of
the threads (such as changing the thread priority) by installing callbacks.
</p>
<p>
MT safe.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>The <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> to use</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>callbacks</code></em> :</span></p></td>
<td>a <a class="link" href="GstTask.html#GstTaskThreadCallbacks" title="GstTaskThreadCallbacks"><span class="type">GstTaskThreadCallbacks</span></a> pointer. <span class="annotation">[<acronym title="Parameter for input. Default is transfer none."><span class="acronym">in</span></acronym>]</span>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>user_data</code></em> :</span></p></td>
<td>user data passed to the callbacks. <span class="annotation">[<acronym title="This parameter is a 'user_data', for callbacks; many bindings can pass NULL here."><span class="acronym">closure</span></acronym>]</span>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>notify</code></em> :</span></p></td>
<td>called when <em class="parameter"><code>user_data</code></em> is no longer referenced</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 0.10.24</p>
</div>
<hr>
<div class="refsect2">
<a name="gst-task-get-state"></a><h3>gst_task_get_state ()</h3>
<pre class="programlisting"><a class="link" href="GstTask.html#GstTaskState" title="enum GstTaskState"><span class="returnvalue">GstTaskState</span></a> gst_task_get_state (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);</pre>
<p>
Get the current state of the task.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>The <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> to query</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>The <a class="link" href="GstTask.html#GstTaskState" title="enum GstTaskState"><span class="type">GstTaskState</span></a> of the task
MT safe.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-task-set-state"></a><h3>gst_task_set_state ()</h3>
<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> gst_task_set_state (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>,
<em class="parameter"><code><a class="link" href="GstTask.html#GstTaskState" title="enum GstTaskState"><span class="type">GstTaskState</span></a> state</code></em>);</pre>
<p>
Sets the state of <em class="parameter"><code>task</code></em> to <em class="parameter"><code>state</code></em>.
</p>
<p>
The <em class="parameter"><code>task</code></em> must have a lock associated with it using
<a class="link" href="GstTask.html#gst-task-set-lock" title="gst_task_set_lock ()"><code class="function">gst_task_set_lock()</code></a> when going to GST_TASK_STARTED or GST_TASK_PAUSED or
this function will return <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a>.
</p>
<p>
MT safe.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>a <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>state</code></em> :</span></p></td>
<td>the new task state</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>
<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the state could be changed.</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 0.10.24</p>
</div>
<hr>
<div class="refsect2">
<a name="gst-task-pause"></a><h3>gst_task_pause ()</h3>
<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> gst_task_pause (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);</pre>
<p>
Pauses <em class="parameter"><code>task</code></em>. This method can also be called on a task in the
stopped state, in which case a thread will be started and will remain
in the paused state. This function does not wait for the task to complete
the paused state.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>The <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> to pause</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>
<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the task could be paused.
MT safe.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-task-start"></a><h3>gst_task_start ()</h3>
<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> gst_task_start (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);</pre>
<p>
Starts <em class="parameter"><code>task</code></em>. The <em class="parameter"><code>task</code></em> must have a lock associated with it using
<a class="link" href="GstTask.html#gst-task-set-lock" title="gst_task_set_lock ()"><code class="function">gst_task_set_lock()</code></a> or this function will return <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>The <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> to start</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>
<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the task could be started.
MT safe.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-task-stop"></a><h3>gst_task_stop ()</h3>
<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> gst_task_stop (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);</pre>
<p>
Stops <em class="parameter"><code>task</code></em>. This method merely schedules the task to stop and
will not wait for the task to have completely stopped. Use
<a class="link" href="GstTask.html#gst-task-join" title="gst_task_join ()"><code class="function">gst_task_join()</code></a> to stop and wait for completion.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>The <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> to stop</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>
<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the task could be stopped.
MT safe.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-task-join"></a><h3>gst_task_join ()</h3>
<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> gst_task_join (<em class="parameter"><code><a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> *task</code></em>);</pre>
<p>
Joins <em class="parameter"><code>task</code></em>. After this call, it is safe to unref the task
and clean up the lock set with <a class="link" href="GstTask.html#gst-task-set-lock" title="gst_task_set_lock ()"><code class="function">gst_task_set_lock()</code></a>.
</p>
<p>
The task will automatically be stopped with this call.
</p>
<p>
This function cannot be called from within a task function as this
would cause a deadlock. The function will detect this and print a
g_warning.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>task</code></em> :</span></p></td>
<td>The <a class="link" href="GstTask.html" title="GstTask"><span class="type">GstTask</span></a> to join</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>
<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the task could be joined.
MT safe.</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="gst-task-cleanup-all"></a><h3>gst_task_cleanup_all ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gst_task_cleanup_all (<em class="parameter"><code><span class="type">void</span></code></em>);</pre>
<p>
Wait for all tasks to be stopped. This is mainly used internally
to ensure proper cleanup of internal data structures in test suites.
</p>
<p>
MT safe.
</p>
</div>
</div>
<div class="refsect1">
<a name="GstTask.see-also"></a><h2>See Also</h2>
<a class="link" href="GstElement.html" title="GstElement"><span class="type">GstElement</span></a>, <a class="link" href="GstPad.html" title="GstPad"><span class="type">GstPad</span></a>
</div>
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