blob: 86f012b3d5de07afa66757806a6b8da67ec48695 [file] [log] [blame]
/* GStreamer
* Copyright (C) 2005 Wim Taymans <wim@fluendo.com>
*
* gstsystemclock.c: Unit test for GstSystemClock
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include <gst/check/gstcheck.h>
static GMutex af_lock;
static GCond af_cond;
/* see if the defines make sense */
GST_START_TEST (test_range)
{
GstClockTime time, time2;
time = GST_SECOND;
fail_unless (time == G_GUINT64_CONSTANT (1000000000));
time2 = time / 1000;
fail_unless (time2 == 1000000);
fail_unless (time2 == GST_MSECOND);
fail_unless (time2 == GST_TIME_AS_USECONDS (time));
time2 = time / 1000000;
fail_unless (time2 == 1000);
fail_unless (time2 == GST_USECOND);
fail_unless (time2 == GST_TIME_AS_MSECONDS (time));
}
GST_END_TEST;
GST_START_TEST (test_signedness)
{
GstClockTime time[] = { 0, 1, G_MAXUINT64 / GST_SECOND };
GstClockTimeDiff diff[] =
{ 0, 1, -1, G_MAXINT64 / GST_SECOND, G_MININT64 / GST_SECOND };
guint i;
for (i = 0; i < G_N_ELEMENTS (time); i++) {
fail_if (time[i] != (time[i] * GST_SECOND / GST_SECOND));
}
for (i = 0; i < G_N_ELEMENTS (diff); i++) {
fail_if (diff[i] != (diff[i] * GST_SECOND / GST_SECOND));
}
}
GST_END_TEST;
#define TIME_UNIT (GST_SECOND / 5)
static void
gst_clock_debug (GstClock * clock)
{
GstClockTime time;
time = gst_clock_get_time (clock);
GST_DEBUG ("Clock info: time %" GST_TIME_FORMAT, GST_TIME_ARGS (time));
}
static gboolean
ok_callback (GstClock * clock, GstClockTime time,
GstClockID id, gpointer user_data)
{
GST_LOG ("unlocked async id %p", id);
return FALSE;
}
static gboolean
error_callback (GstClock * clock, GstClockTime time,
GstClockID id, gpointer user_data)
{
GST_WARNING ("unlocked unscheduled async id %p, this is wrong", id);
fail_if (TRUE);
return FALSE;
}
GMutex store_lock;
static gboolean
store_callback (GstClock * clock, GstClockTime time,
GstClockID id, gpointer user_data)
{
GList **list = user_data;
GST_DEBUG ("unlocked async id %p", id);
g_mutex_lock (&store_lock);
*list = g_list_append (*list, id);
g_mutex_unlock (&store_lock);
return FALSE;
}
static gboolean
notify_callback (GstClock * clock, GstClockTime time,
GstClockID id, gpointer user_data)
{
gboolean *ret = (gboolean *) user_data;
if (ret != NULL)
*ret = TRUE;
return FALSE;
}
GST_START_TEST (test_set_default)
{
GstClock *clock, *static_clock;
/* obtain the default system clock, which keeps a static ref and bumps the
* refcount before returning */
static_clock = gst_system_clock_obtain ();
fail_unless (static_clock != NULL, "Could not create default system clock");
g_assert_cmpint (GST_OBJECT_REFCOUNT (static_clock), ==, 2);
/* set a new default clock to a different instance which should replace the
* static clock with this one, and unref the static clock */
clock = g_object_new (GST_TYPE_SYSTEM_CLOCK, "name", "TestClock", NULL);
gst_system_clock_set_default (clock);
g_assert_cmpint (GST_OBJECT_REFCOUNT (static_clock), ==, 1);
g_object_unref (static_clock);
static_clock = gst_system_clock_obtain ();
fail_unless (static_clock == clock);
g_assert_cmpint (GST_OBJECT_REFCOUNT (clock), ==, 3);
g_object_unref (static_clock);
/* Reset the default clock to the static one */
gst_system_clock_set_default (NULL);
static_clock = gst_system_clock_obtain ();
fail_unless (static_clock != clock);
g_assert_cmpint (GST_OBJECT_REFCOUNT (clock), ==, 1);
g_assert_cmpint (GST_OBJECT_REFCOUNT (static_clock), ==, 2);
g_object_unref (clock);
g_object_unref (static_clock);
}
GST_END_TEST;
GST_START_TEST (test_single_shot)
{
GstClock *clock;
GstClockID id, id2;
GstClockTime base;
GstClockReturn result;
clock = gst_system_clock_obtain ();
fail_unless (clock != NULL, "Could not create instance of GstSystemClock");
gst_clock_debug (clock);
base = gst_clock_get_time (clock);
id = gst_clock_new_single_shot_id (clock, base + TIME_UNIT);
fail_unless (id != NULL, "Could not create single shot id");
GST_DEBUG ("waiting one time unit");
result = gst_clock_id_wait (id, NULL);
gst_clock_debug (clock);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK (result=%d)",
result);
fail_unless (gst_clock_get_time (clock) > (base + TIME_UNIT),
"target time has not been reached");
GST_DEBUG ("waiting in the past");
result = gst_clock_id_wait (id, NULL);
gst_clock_debug (clock);
fail_unless (result == GST_CLOCK_EARLY,
"Waiting did not return EARLY(result=%d)", result);
gst_clock_id_unref (id);
id = gst_clock_new_single_shot_id (clock, base + 2 * TIME_UNIT);
GST_DEBUG ("waiting one second async id %p", id);
result = gst_clock_id_wait_async (id, ok_callback, NULL, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
g_usleep (TIME_UNIT / (2 * 1000));
gst_clock_id_unschedule (id);
gst_clock_id_unref (id);
id = gst_clock_new_single_shot_id (clock, base + 5 * TIME_UNIT);
GST_DEBUG ("waiting one second async, with cancel on id %p", id);
result = gst_clock_id_wait_async (id, error_callback, NULL, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
g_usleep (TIME_UNIT / (2 * 1000));
GST_DEBUG ("cancel id %p after half a time unit", id);
gst_clock_id_unschedule (id);
gst_clock_id_unref (id);
GST_DEBUG ("canceled id %p", id);
GST_DEBUG ("waiting multiple one second async, with cancel");
id = gst_clock_new_single_shot_id (clock, base + 5 * TIME_UNIT);
id2 = gst_clock_new_single_shot_id (clock, base + 6 * TIME_UNIT);
GST_DEBUG ("waiting id %p", id);
result = gst_clock_id_wait_async (id, ok_callback, NULL, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
GST_DEBUG ("waiting id %p", id2);
result = gst_clock_id_wait_async (id2, error_callback, NULL, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
g_usleep (TIME_UNIT / (2 * 1000));
GST_DEBUG ("cancel id %p after half a time unit", id2);
gst_clock_id_unschedule (id2);
GST_DEBUG ("canceled id %p", id2);
gst_clock_id_unref (id2);
/* wait for the entry to time out */
g_usleep (TIME_UNIT / 1000 * 5);
fail_unless (((GstClockEntry *) id)->status == GST_CLOCK_OK,
"Waiting did not finish");
gst_clock_id_unref (id);
gst_object_unref (clock);
}
GST_END_TEST;
GST_START_TEST (test_periodic_shot)
{
GstClock *clock;
GstClockID id, id2;
GstClockTime base;
GstClockReturn result;
clock = gst_system_clock_obtain ();
fail_unless (clock != NULL, "Could not create instance of GstSystemClock");
gst_clock_debug (clock);
base = gst_clock_get_time (clock);
/* signal every half a time unit */
id = gst_clock_new_periodic_id (clock, base + TIME_UNIT, TIME_UNIT / 2);
fail_unless (id != NULL, "Could not create periodic id");
GST_DEBUG ("waiting one time unit");
result = gst_clock_id_wait (id, NULL);
gst_clock_debug (clock);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
GST_DEBUG ("waiting for the next");
result = gst_clock_id_wait (id, NULL);
gst_clock_debug (clock);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
GST_DEBUG ("waiting for the next async %p", id);
result = gst_clock_id_wait_async (id, ok_callback, NULL, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
g_usleep (TIME_UNIT / (2 * 1000));
GST_DEBUG ("waiting some more for the next async %p", id);
result = gst_clock_id_wait_async (id, ok_callback, NULL, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
g_usleep (TIME_UNIT / (2 * 1000));
id2 = gst_clock_new_periodic_id (clock, base + TIME_UNIT, TIME_UNIT / 2);
fail_unless (id2 != NULL, "Could not create second periodic id");
GST_DEBUG ("waiting some more for another async %p", id2);
result = gst_clock_id_wait_async (id2, ok_callback, NULL, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
g_usleep (TIME_UNIT / (2 * 1000));
GST_DEBUG ("unschedule %p", id);
gst_clock_id_unschedule (id);
/* entry cannot be used again */
result = gst_clock_id_wait_async (id, error_callback, NULL, NULL);
fail_unless (result == GST_CLOCK_UNSCHEDULED,
"Waiting did not return UNSCHEDULED");
result = gst_clock_id_wait (id, NULL);
fail_unless (result == GST_CLOCK_UNSCHEDULED,
"Waiting did not return UNSCHEDULED");
g_usleep (TIME_UNIT / (2 * 1000));
/* clean up */
gst_clock_id_unref (id);
gst_clock_id_unschedule (id2);
gst_clock_id_unref (id2);
gst_object_unref (clock);
}
GST_END_TEST;
GST_START_TEST (test_async_order)
{
GstClock *clock;
GstClockID id1, id2;
GList *cb_list = NULL, *next;
GstClockTime base;
GstClockReturn result;
clock = gst_system_clock_obtain ();
fail_unless (clock != NULL, "Could not create instance of GstSystemClock");
gst_clock_debug (clock);
base = gst_clock_get_time (clock);
id1 = gst_clock_new_single_shot_id (clock, base + 2 * TIME_UNIT);
id2 = gst_clock_new_single_shot_id (clock, base + 1 * TIME_UNIT);
result = gst_clock_id_wait_async (id1, store_callback, &cb_list, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
g_usleep (TIME_UNIT / (2 * 1000));
result = gst_clock_id_wait_async (id2, store_callback, &cb_list, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
g_usleep (TIME_UNIT / 1000);
/* at this point at least one of the timers should have timed out */
g_mutex_lock (&store_lock);
fail_unless (cb_list != NULL, "expected notification");
fail_unless (cb_list->data == id2,
"Expected notification for id2 to come first");
g_mutex_unlock (&store_lock);
g_usleep (TIME_UNIT / 1000);
g_mutex_lock (&store_lock);
/* now both should have timed out */
next = g_list_next (cb_list);
fail_unless (next != NULL, "expected second notification");
fail_unless (next->data == id1, "Missing notification for id1");
g_mutex_unlock (&store_lock);
gst_clock_id_unref (id1);
gst_clock_id_unref (id2);
g_list_free (cb_list);
gst_object_unref (clock);
}
GST_END_TEST;
struct test_async_sync_interaction_data
{
GMutex lock;
GstClockID sync_id;
GstClockID sync_id2;
GstClockID async_id;
GstClockID async_id2;
GstClockID async_id3;
};
static gboolean
test_async_sync_interaction_cb (GstClock * clock, GstClockTime time,
GstClockID id, gpointer user_data)
{
struct test_async_sync_interaction_data *td =
(struct test_async_sync_interaction_data *) (user_data);
g_mutex_lock (&td->lock);
/* The first async callback is ignored */
if (id == td->async_id)
goto out;
if (id != td->async_id2 && id != td->async_id3)
goto out;
/* Unschedule the sync callback */
if (id == td->async_id3) {
gst_clock_id_unschedule (td->sync_id);
gst_clock_id_unschedule (td->async_id2);
}
out:
g_mutex_unlock (&td->lock);
return FALSE;
}
GST_START_TEST (test_async_sync_interaction)
{
/* This test schedules an async callback, then before it completes, schedules
* an earlier async callback, and quickly unschedules the first, and inserts
* a THIRD even earlier async callback. It then attempts to wait on a
* sync clock ID. While that's sleeping, the 3rd async callback should fire
* and unschedule it. This tests for problems with unscheduling async and
* sync callbacks on the system clock. */
GstClock *clock;
GstClockReturn result;
GstClockTime base;
GstClockTimeDiff jitter;
struct test_async_sync_interaction_data td;
int i;
clock = gst_system_clock_obtain ();
fail_unless (clock != NULL, "Could not create instance of GstSystemClock");
g_mutex_init (&td.lock);
for (i = 0; i < 50; i++) {
gst_clock_debug (clock);
base = gst_clock_get_time (clock);
g_mutex_lock (&td.lock);
td.async_id = gst_clock_new_single_shot_id (clock, base + 40 * GST_MSECOND);
td.async_id2 =
gst_clock_new_single_shot_id (clock, base + 30 * GST_MSECOND);
td.async_id3 =
gst_clock_new_single_shot_id (clock, base + 20 * GST_MSECOND);
td.sync_id2 = gst_clock_new_single_shot_id (clock, base + 10 * GST_MSECOND);
td.sync_id = gst_clock_new_single_shot_id (clock, base + 50 * GST_MSECOND);
g_mutex_unlock (&td.lock);
result = gst_clock_id_wait_async (td.async_id,
test_async_sync_interaction_cb, &td, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
/* Wait 10ms, then unschedule async_id and schedule async_id2 */
result = gst_clock_id_wait (td.sync_id2, &jitter);
fail_unless (result == GST_CLOCK_OK || result == GST_CLOCK_EARLY,
"Waiting did not return OK or EARLY");
/* async_id2 is earlier than async_id - should become head of the queue */
result = gst_clock_id_wait_async (td.async_id2,
test_async_sync_interaction_cb, &td, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
gst_clock_id_unschedule (td.async_id);
/* async_id3 is earlier than async_id2 - should become head of the queue */
result = gst_clock_id_wait_async (td.async_id3,
test_async_sync_interaction_cb, &td, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
/* While this is sleeping, the async3 id should fire and unschedule it */
result = gst_clock_id_wait (td.sync_id, &jitter);
fail_unless (result == GST_CLOCK_UNSCHEDULED || result == GST_CLOCK_EARLY,
"Waiting did not return UNSCHEDULED (was %d)", result);
gst_clock_id_unschedule (td.async_id3);
g_mutex_lock (&td.lock);
gst_clock_id_unref (td.sync_id);
gst_clock_id_unref (td.sync_id2);
gst_clock_id_unref (td.async_id);
gst_clock_id_unref (td.async_id2);
gst_clock_id_unref (td.async_id3);
g_mutex_unlock (&td.lock);
}
g_mutex_clear (&td.lock);
gst_object_unref (clock);
}
GST_END_TEST;
GST_START_TEST (test_periodic_multi)
{
GstClock *clock;
GstClockID clock_id;
GstClockID clock_id_async;
GstClockTime base;
GstClockReturn result;
gboolean got_callback = FALSE;
clock = gst_system_clock_obtain ();
fail_unless (clock != NULL, "Could not create instance of GstSystemClock");
gst_clock_debug (clock);
base = gst_clock_get_time (clock);
clock_id = gst_clock_new_periodic_id (clock, base + TIME_UNIT, TIME_UNIT);
gst_clock_id_wait (clock_id, NULL);
fail_unless (gst_clock_get_time (clock) >= base + TIME_UNIT);
fail_unless (gst_clock_get_time (clock) < base + 2 * TIME_UNIT);
/* now perform a concurrent wait and wait_async */
clock_id_async =
gst_clock_new_periodic_id (clock, base + TIME_UNIT, TIME_UNIT);
result =
gst_clock_id_wait_async (clock_id_async, notify_callback, &got_callback,
NULL);
fail_unless (result == GST_CLOCK_OK, "Async waiting did not return OK");
result = gst_clock_id_wait (clock_id, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
fail_unless (gst_clock_get_time (clock) >= base + 2 * TIME_UNIT);
/* give the async thread some time to call our callback: */
g_usleep (TIME_UNIT / (10 * 1000));
fail_unless (got_callback == TRUE, "got no async callback (1)");
fail_unless (gst_clock_get_time (clock) < base + 3 * TIME_UNIT);
got_callback = FALSE;
result = gst_clock_id_wait (clock_id, NULL);
fail_unless (result == GST_CLOCK_OK, "Waiting did not return OK");
fail_unless (gst_clock_get_time (clock) >= base + 3 * TIME_UNIT);
/* give the async thread some time to call our callback: */
g_usleep (TIME_UNIT / (10 * 1000));
fail_unless (got_callback == TRUE, "got no async callback (2)");
fail_unless (gst_clock_get_time (clock) < base + 4 * TIME_UNIT);
/* clean up */
gst_clock_id_unref (clock_id);
gst_clock_id_unschedule (clock_id_async);
gst_clock_id_unref (clock_id_async);
gst_object_unref (clock);
}
GST_END_TEST;
GST_START_TEST (test_diff)
{
GstClockTime time1[] = { 0, (GstClockTime) - 1, 0, 1, 2 * GST_SECOND,
(GstClockTime) - GST_SECOND, (GstClockTime) - GST_SECOND
};
GstClockTime time2[] =
{ 0, 1, 1, 0, 1 * GST_SECOND, (GstClockTime) - GST_SECOND, GST_SECOND };
GstClockTimeDiff d[] = { 0, 2, 1, -1, -GST_SECOND, 0, 2 * GST_SECOND };
guint i;
for (i = 0; i < G_N_ELEMENTS (d); i++) {
fail_if (d[i] != GST_CLOCK_DIFF (time1[i], time2[i]));
}
}
GST_END_TEST;
/* test if a blocking wait, unblocked by an async entry continues to be
* scheduled */
typedef struct
{
GstClock *clock;
GstClockID id;
GstClockTimeDiff jitter;
GstClockReturn ret;
} MixedInfo;
static gpointer
mixed_thread (MixedInfo * info)
{
info->ret = gst_clock_id_wait (info->id, &info->jitter);
return NULL;
}
static gboolean
mixed_async_cb (GstClock * clock, GstClockTime time,
GstClockID id, gpointer user_data)
{
return TRUE;
}
GST_START_TEST (test_mixed)
{
GThread *thread;
GError *error = NULL;
MixedInfo info;
GstClockTime base;
GstClockID id;
info.clock = gst_system_clock_obtain ();
fail_unless (info.clock != NULL,
"Could not create instance of GstSystemClock");
/* get current time of the clock as base time */
base = gst_clock_get_time (info.clock);
/* create entry to wait for 1 second */
info.id = gst_clock_new_single_shot_id (info.clock, base + GST_SECOND);
/* make and start an entry that is scheduled every 10ms */
id = gst_clock_new_periodic_id (info.clock, base, 10 * GST_MSECOND);
/* start waiting for the entry */
thread =
g_thread_try_new ("gst-check", (GThreadFunc) mixed_thread, &info, &error);
fail_unless (error == NULL, "error creating thread");
fail_unless (thread != NULL, "Could not create thread");
/* wait half a second so we are sure to be in the thread */
g_usleep (G_USEC_PER_SEC / 2);
/* start scheduling the entry */
gst_clock_id_wait_async (id, mixed_async_cb, NULL, NULL);
/* wait for thread to finish */
g_thread_join (thread);
/* entry must have timed out correctly */
fail_unless (info.ret == GST_CLOCK_OK, "clock return was %d", info.ret);
gst_clock_id_unschedule (id);
gst_clock_id_unref (id);
gst_clock_id_unref (info.id);
gst_object_unref (info.clock);
}
GST_END_TEST;
static gboolean
test_async_full_slave_callback (GstClock * master, GstClockTime time,
GstClockID id, GstClock * clock)
{
GstClockTime stime, mtime;
gdouble r_squared;
/* notify the test case that we started */
GST_INFO ("callback started");
g_mutex_lock (&af_lock);
g_cond_signal (&af_cond);
/* wait for the test case to unref "clock" and signal */
GST_INFO ("waiting for test case to signal");
g_cond_wait (&af_cond, &af_lock);
stime = gst_clock_get_internal_time (clock);
mtime = gst_clock_get_time (master);
gst_clock_add_observation (clock, stime, mtime, &r_squared);
g_cond_signal (&af_cond);
g_mutex_unlock (&af_lock);
GST_INFO ("callback finished");
return TRUE;
}
GST_START_TEST (test_async_full)
{
GstClock *master, *slave;
GstClockID *clockid;
/* create master and slave */
master =
g_object_new (GST_TYPE_SYSTEM_CLOCK, "name", "TestClockMaster", NULL);
slave = g_object_new (GST_TYPE_SYSTEM_CLOCK, "name", "TestClockMaster", NULL);
GST_OBJECT_FLAG_SET (slave, GST_CLOCK_FLAG_CAN_SET_MASTER);
g_object_set (slave, "timeout", 50 * GST_MSECOND, NULL);
fail_unless (GST_OBJECT_REFCOUNT (master) == 1);
fail_unless (GST_OBJECT_REFCOUNT (slave) == 1);
/* register a periodic shot on the master to calibrate the slave */
g_mutex_lock (&af_lock);
clockid = gst_clock_new_periodic_id (master,
gst_clock_get_time (master), gst_clock_get_timeout (slave));
gst_clock_id_wait_async (clockid,
(GstClockCallback) test_async_full_slave_callback,
gst_object_ref (slave), (GDestroyNotify) gst_object_unref);
/* wait for the shot to be fired and test_async_full_slave_callback to be
* called */
GST_INFO ("waiting for the slave callback to start");
g_cond_wait (&af_cond, &af_lock);
GST_INFO ("slave callback running, unreffing slave");
/* unref the slave clock while the slave_callback is running. This should be
* safe since the master clock now stores a ref to the slave */
gst_object_unref (slave);
/* unref the clock entry. This should be safe as well since the clock thread
* refs the entry before executing it */
gst_clock_id_unschedule (clockid);
gst_clock_id_unref (clockid);
/* signal and wait for the callback to complete */
g_cond_signal (&af_cond);
GST_INFO ("waiting for callback to finish");
g_cond_wait (&af_cond, &af_lock);
GST_INFO ("callback finished");
g_mutex_unlock (&af_lock);
gst_object_unref (master);
}
GST_END_TEST;
static Suite *
gst_systemclock_suite (void)
{
Suite *s = suite_create ("GstSystemClock");
TCase *tc_chain = tcase_create ("waiting");
suite_add_tcase (s, tc_chain);
tcase_add_test (tc_chain, test_range);
tcase_add_test (tc_chain, test_signedness);
tcase_add_test (tc_chain, test_single_shot);
tcase_add_test (tc_chain, test_periodic_shot);
tcase_add_test (tc_chain, test_periodic_multi);
tcase_add_test (tc_chain, test_async_order);
tcase_add_test (tc_chain, test_async_sync_interaction);
tcase_add_test (tc_chain, test_diff);
tcase_add_test (tc_chain, test_mixed);
tcase_add_test (tc_chain, test_async_full);
tcase_add_test (tc_chain, test_set_default);
return s;
}
GST_CHECK_MAIN (gst_systemclock);