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<div id="projectname">Jack2
 <span id="projectnumber">1.9.9</span>
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<a href="#func-members">Functions</a> </div>
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<div class="title">Transport and Timebase control</div> </div>
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<tr class="heading"><td colspan="2"><h2><a name="func-members"></a>
Functions</h2></td></tr>
<tr class="memitem:gaea06ff63b129ec6266b2b805b6c8216a"><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#gaea06ff63b129ec6266b2b805b6c8216a">jack_release_timebase</a> (jack_client_t *client) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
<tr class="memitem:gae53f7ac54804d2896d51b6ad599fa93c"><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#gae53f7ac54804d2896d51b6ad599fa93c">jack_set_sync_callback</a> (jack_client_t *client, JackSyncCallback sync_callback, void *arg) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
<tr class="memitem:ga2e89b0bb8702d34bcbbe1eac70685ab2"><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#ga2e89b0bb8702d34bcbbe1eac70685ab2">jack_set_sync_timeout</a> (jack_client_t *client, jack_time_t timeout) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
<tr class="memitem:ga0c2f2f464f6ba1c0b2aa45e6507b7aa9"><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#ga0c2f2f464f6ba1c0b2aa45e6507b7aa9">jack_set_timebase_callback</a> (jack_client_t *client, int conditional, JackTimebaseCallback timebase_callback, void *arg) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
<tr class="memitem:gab3f52a42084aead87fd1ee75ed25b240"><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#gab3f52a42084aead87fd1ee75ed25b240">jack_transport_locate</a> (jack_client_t *client, jack_nframes_t frame) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
<tr class="memitem:ga5f08eb71a5ee5431a3d756af5729d5aa"><td class="memItemLeft" align="right" valign="top">jack_transport_state_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#ga5f08eb71a5ee5431a3d756af5729d5aa">jack_transport_query</a> (const jack_client_t *client, <a class="el" href="struct__jack__position.html">jack_position_t</a> *pos) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
<tr class="memitem:gaef1df9479faa3b7f400c787be173f805"><td class="memItemLeft" align="right" valign="top">jack_nframes_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#gaef1df9479faa3b7f400c787be173f805">jack_get_current_transport_frame</a> (const jack_client_t *client) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
<tr class="memitem:ga2f371010358add3cbed8454bd0bd2ef8"><td class="memItemLeft" align="right" valign="top">int </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#ga2f371010358add3cbed8454bd0bd2ef8">jack_transport_reposition</a> (jack_client_t *client, const <a class="el" href="struct__jack__position.html">jack_position_t</a> *pos) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
<tr class="memitem:gab7b158bec8f27c03da29795f142d1caf"><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#gab7b158bec8f27c03da29795f142d1caf">jack_transport_start</a> (jack_client_t *client) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
<tr class="memitem:ga6be6637c314bd88344826e9bcc1957b0"><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#ga6be6637c314bd88344826e9bcc1957b0">jack_transport_stop</a> (jack_client_t *client) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
<tr class="memitem:gaa3f548f66e8c9a4f271ef97a87ecb240"><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#gaa3f548f66e8c9a4f271ef97a87ecb240">jack_get_transport_info</a> (jack_client_t *client, <a class="el" href="structjack__transport__info__t.html">jack_transport_info_t</a> *tinfo) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
<tr class="memitem:ga2539e041b424eab678e7ba1ee4777579"><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="group__TransportControl.html#ga2539e041b424eab678e7ba1ee4777579">jack_set_transport_info</a> (jack_client_t *client, <a class="el" href="structjack__transport__info__t.html">jack_transport_info_t</a> *tinfo) JACK_OPTIONAL_WEAK_EXPORT</td></tr>
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<hr/><a name="details" id="details"></a><h2>Detailed Description</h2>
<hr/><h2>Function Documentation</h2>
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<td class="memname">int jack_release_timebase </td>
<td>(</td>
<td class="paramtype">jack_client_t * </td>
<td class="paramname"><em>client</em></td><td>)</td>
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<p>Called by the timebase master to release itself from that responsibility.</p>
<p>If the timebase master releases the timebase or leaves the JACK graph for any reason, the JACK engine takes over at the start of the next process cycle. The transport state does not change. If rolling, it continues to play, with frame numbers as the only available position information.</p>
<dl class="section see"><dt>See also:</dt><dd><a class="el" href="group__TransportControl.html#ga0c2f2f464f6ba1c0b2aa45e6507b7aa9">jack_set_timebase_callback</a></dd></dl>
<dl class="params"><dt>Parameters:</dt><dd>
<table class="params">
<tr><td class="paramname">client</td><td>the JACK client structure.</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns:</dt><dd>0 on success, otherwise a non-zero error code. </dd></dl>
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<td class="memname">int jack_set_sync_callback </td>
<td>(</td>
<td class="paramtype">jack_client_t * </td>
<td class="paramname"><em>client</em>, </td>
</tr>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype">JackSyncCallback </td>
<td class="paramname"><em>sync_callback</em>, </td>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype">void * </td>
<td class="paramname"><em>arg</em> </td>
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<p>Register (or unregister) as a slow-sync client, one that cannot respond immediately to transport position changes.</p>
<p>The <em>sync_callback</em> will be invoked at the first available opportunity after its registration is complete. If the client is currently active this will be the following process cycle, otherwise it will be the first cycle after calling <a class="el" href="group__ClientFunctions.html#ga9800d5b29bd7670d9944a15f6ea0ecf8">jack_activate()</a>. After that, it runs according to the ::JackSyncCallback rules. Clients that don't set a <em>sync_callback</em> are assumed to be ready immediately any time the transport wants to start.</p>
<dl class="params"><dt>Parameters:</dt><dd>
<table class="params">
<tr><td class="paramname">client</td><td>the JACK client structure. </td></tr>
<tr><td class="paramname">sync_callback</td><td>is a realtime function that returns TRUE when the client is ready. Setting <em>sync_callback</em> to NULL declares that this client no longer requires slow-sync processing. </td></tr>
<tr><td class="paramname">arg</td><td>an argument for the <em>sync_callback</em> function.</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns:</dt><dd>0 on success, otherwise a non-zero error code. </dd></dl>
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<td class="memname">int jack_set_sync_timeout </td>
<td>(</td>
<td class="paramtype">jack_client_t * </td>
<td class="paramname"><em>client</em>, </td>
</tr>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype">jack_time_t </td>
<td class="paramname"><em>timeout</em> </td>
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<td>)</td>
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<p>Set the timeout value for slow-sync clients.</p>
<p>This timeout prevents unresponsive slow-sync clients from completely halting the transport mechanism. The default is two seconds. When the timeout expires, the transport starts rolling, even if some slow-sync clients are still unready. The <em>sync_callbacks</em> of these clients continue being invoked, giving them a chance to catch up.</p>
<dl class="section see"><dt>See also:</dt><dd><a class="el" href="group__TransportControl.html#gae53f7ac54804d2896d51b6ad599fa93c">jack_set_sync_callback</a></dd></dl>
<dl class="params"><dt>Parameters:</dt><dd>
<table class="params">
<tr><td class="paramname">client</td><td>the JACK client structure. </td></tr>
<tr><td class="paramname">timeout</td><td>is delay (in microseconds) before the timeout expires.</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns:</dt><dd>0 on success, otherwise a non-zero error code. </dd></dl>
</div>
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<td class="memname">int jack_set_timebase_callback </td>
<td>(</td>
<td class="paramtype">jack_client_t * </td>
<td class="paramname"><em>client</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">int </td>
<td class="paramname"><em>conditional</em>, </td>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype">JackTimebaseCallback </td>
<td class="paramname"><em>timebase_callback</em>, </td>
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<td class="paramtype">void * </td>
<td class="paramname"><em>arg</em> </td>
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<p>Register as timebase master for the JACK subsystem.</p>
<p>The timebase master registers a callback that updates extended position information such as beats or timecode whenever necessary. Without this extended information, there is no need for this function.</p>
<p>There is never more than one master at a time. When a new client takes over, the former <em>timebase_callback</em> is no longer called. Taking over the timebase may be done conditionally, so it fails if there was a master already.</p>
<dl class="params"><dt>Parameters:</dt><dd>
<table class="params">
<tr><td class="paramname">client</td><td>the JACK client structure. </td></tr>
<tr><td class="paramname">conditional</td><td>non-zero for a conditional request. </td></tr>
<tr><td class="paramname">timebase_callback</td><td>is a realtime function that returns position information. </td></tr>
<tr><td class="paramname">arg</td><td>an argument for the <em>timebase_callback</em> function.</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns:</dt><dd><ul>
<li>0 on success;</li>
<li>EBUSY if a conditional request fails because there was already a timebase master;</li>
<li>other non-zero error code. </li>
</ul>
</dd></dl>
</div>
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<td class="memname">int jack_transport_locate </td>
<td>(</td>
<td class="paramtype">jack_client_t * </td>
<td class="paramname"><em>client</em>, </td>
</tr>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype">jack_nframes_t </td>
<td class="paramname"><em>frame</em> </td>
</tr>
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<td></td>
<td>)</td>
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<p>Reposition the transport to a new frame number.</p>
<p>May be called at any time by any client. The new position takes effect in two process cycles. If there are slow-sync clients and the transport is already rolling, it will enter the ::JackTransportStarting state and begin invoking their <em>sync_callbacks</em> until ready. This function is realtime-safe.</p>
<dl class="section see"><dt>See also:</dt><dd><a class="el" href="group__TransportControl.html#ga2f371010358add3cbed8454bd0bd2ef8">jack_transport_reposition</a>, <a class="el" href="group__TransportControl.html#gae53f7ac54804d2896d51b6ad599fa93c">jack_set_sync_callback</a></dd></dl>
<dl class="params"><dt>Parameters:</dt><dd>
<table class="params">
<tr><td class="paramname">client</td><td>the JACK client structure. </td></tr>
<tr><td class="paramname">frame</td><td>frame number of new transport position.</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns:</dt><dd>0 if valid request, non-zero otherwise. </dd></dl>
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<td class="memname">jack_transport_state_t jack_transport_query </td>
<td>(</td>
<td class="paramtype">const jack_client_t * </td>
<td class="paramname"><em>client</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="struct__jack__position.html">jack_position_t</a> * </td>
<td class="paramname"><em>pos</em> </td>
</tr>
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<p>Query the current transport state and position.</p>
<p>This function is realtime-safe, and can be called from any thread. If called from the process thread, <em>pos</em> corresponds to the first frame of the current cycle and the state returned is valid for the entire cycle.</p>
<dl class="params"><dt>Parameters:</dt><dd>
<table class="params">
<tr><td class="paramname">client</td><td>the JACK client structure. </td></tr>
<tr><td class="paramname">pos</td><td>pointer to structure for returning current transport position; <em>pos->valid</em> will show which fields contain valid data. If <em>pos</em> is NULL, do not return position information.</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns:</dt><dd>Current transport state. </dd></dl>
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<td class="memname">jack_nframes_t jack_get_current_transport_frame </td>
<td>(</td>
<td class="paramtype">const jack_client_t * </td>
<td class="paramname"><em>client</em></td><td>)</td>
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<p>Return an estimate of the current transport frame, including any time elapsed since the last transport positional update.</p>
<dl class="params"><dt>Parameters:</dt><dd>
<table class="params">
<tr><td class="paramname">client</td><td>the JACK client structure </td></tr>
</table>
</dd>
</dl>
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<td class="memname">int jack_transport_reposition </td>
<td>(</td>
<td class="paramtype">jack_client_t * </td>
<td class="paramname"><em>client</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype">const <a class="el" href="struct__jack__position.html">jack_position_t</a> * </td>
<td class="paramname"><em>pos</em> </td>
</tr>
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<td></td>
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<p>Request a new transport position.</p>
<p>May be called at any time by any client. The new position takes effect in two process cycles. If there are slow-sync clients and the transport is already rolling, it will enter the ::JackTransportStarting state and begin invoking their <em>sync_callbacks</em> until ready. This function is realtime-safe.</p>
<dl class="section see"><dt>See also:</dt><dd><a class="el" href="group__TransportControl.html#gab3f52a42084aead87fd1ee75ed25b240">jack_transport_locate</a>, <a class="el" href="group__TransportControl.html#gae53f7ac54804d2896d51b6ad599fa93c">jack_set_sync_callback</a></dd></dl>
<dl class="params"><dt>Parameters:</dt><dd>
<table class="params">
<tr><td class="paramname">client</td><td>the JACK client structure. </td></tr>
<tr><td class="paramname">pos</td><td>requested new transport position.</td></tr>
</table>
</dd>
</dl>
<dl class="section return"><dt>Returns:</dt><dd>0 if valid request, EINVAL if position structure rejected. </dd></dl>
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<td class="memname">void jack_transport_start </td>
<td>(</td>
<td class="paramtype">jack_client_t * </td>
<td class="paramname"><em>client</em></td><td>)</td>
<td></td>
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<p>Start the JACK transport rolling.</p>
<p>Any client can make this request at any time. It takes effect no sooner than the next process cycle, perhaps later if there are slow-sync clients. This function is realtime-safe.</p>
<dl class="section see"><dt>See also:</dt><dd><a class="el" href="group__TransportControl.html#gae53f7ac54804d2896d51b6ad599fa93c">jack_set_sync_callback</a></dd></dl>
<dl class="params"><dt>Parameters:</dt><dd>
<table class="params">
<tr><td class="paramname">client</td><td>the JACK client structure. </td></tr>
</table>
</dd>
</dl>
</div>
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<td class="memname">void jack_transport_stop </td>
<td>(</td>
<td class="paramtype">jack_client_t * </td>
<td class="paramname"><em>client</em></td><td>)</td>
<td></td>
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<p>Stop the JACK transport.</p>
<p>Any client can make this request at any time. It takes effect on the next process cycle. This function is realtime-safe.</p>
<dl class="params"><dt>Parameters:</dt><dd>
<table class="params">
<tr><td class="paramname">client</td><td>the JACK client structure. </td></tr>
</table>
</dd>
</dl>
</div>
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<td class="memname">void jack_get_transport_info </td>
<td>(</td>
<td class="paramtype">jack_client_t * </td>
<td class="paramname"><em>client</em>, </td>
</tr>
<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="structjack__transport__info__t.html">jack_transport_info_t</a> * </td>
<td class="paramname"><em>tinfo</em> </td>
</tr>
<tr>
<td></td>
<td>)</td>
<td></td><td></td>
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<p>Gets the current transport info structure (deprecated).</p>
<dl class="params"><dt>Parameters:</dt><dd>
<table class="params">
<tr><td class="paramname">client</td><td>the JACK client structure. </td></tr>
<tr><td class="paramname">tinfo</td><td>current transport info structure. The "valid" field describes which fields contain valid data.</td></tr>
</table>
</dd>
</dl>
<dl class="deprecated"><dt><b><a class="el" href="deprecated.html#_deprecated000012">Deprecated:</a></b></dt><dd>This is for compatibility with the earlier transport interface. Use <a class="el" href="group__TransportControl.html#ga5f08eb71a5ee5431a3d756af5729d5aa">jack_transport_query()</a>, instead.</dd></dl>
<dl class="section pre"><dt>Precondition:</dt><dd>Must be called from the process thread. </dd></dl>
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<td class="memname">void jack_set_transport_info </td>
<td>(</td>
<td class="paramtype">jack_client_t * </td>
<td class="paramname"><em>client</em>, </td>
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<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="structjack__transport__info__t.html">jack_transport_info_t</a> * </td>
<td class="paramname"><em>tinfo</em> </td>
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<td></td>
<td>)</td>
<td></td><td></td>
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</div><div class="memdoc">
<p>Set the transport info structure (deprecated).</p>
<dl class="deprecated"><dt><b><a class="el" href="deprecated.html#_deprecated000013">Deprecated:</a></b></dt><dd>This function still exists for compatibility with the earlier transport interface, but it does nothing. Instead, define a ::JackTimebaseCallback. </dd></dl>
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