diff --git a/src/tl/tl/tlThreads.cc b/src/tl/tl/tlThreads.cc
index dc85cce1b..c2e5c6e15 100644
--- a/src/tl/tl/tlThreads.cc
+++ b/src/tl/tl/tlThreads.cc
@@ -36,27 +36,124 @@ namespace tl
 // -------------------------------------------------------------------------------
 //  WaitCondition implementation
 
+
+class WaitConditionPrivate
+{
+public:
+  WaitConditionPrivate ()
+    : m_initialized (false)
+  {
+    if (pthread_mutex_init (&m_mutex, NULL) != 0) {
+      tl::error << tr ("Unable to create pthread Mutex for WaitCondition");
+    } else if (pthread_cond_init(&m_cond, NULL) != 0) {
+      tl::error << tr ("Unable to create pthread Condition for WaitCondition");
+    } else {
+      m_initialized = true;
+    }
+  }
+
+  ~WaitConditionPrivate ()
+  {
+    if (m_initialized) {
+      pthread_cond_destroy (&m_cond);
+      pthread_mutex_destroy (&m_mutex);
+    }
+  }
+
+  bool wait (Mutex *mutex, unsigned long time)
+  {
+    if (! m_initialized) {
+      return false;
+    }
+
+    //  transfer the lock from our own implementation to the pthread mutex
+    pthread_mutex_lock (&m_mutex);
+    mutex->unlock ();
+
+    //  this code is executed concurrently ...
+
+    bool woken = true;
+
+    if (time < std::numeric_limits<unsigned long>::max ()) {
+
+      struct timespec end_time;
+      clock_gettime (CLOCK_REALTIME, &end_time);
+
+      end_time.tv_sec += (time / 1000);
+      end_time.tv_nsec += (time % 1000) * 1000000;
+      if (end_time.tv_nsec > 1000000000) {
+        end_time.tv_nsec -= 1000000000;
+        end_time.tv_sec += 1;
+      }
+
+      int res = pthread_cond_timedwait (&m_cond, &m_mutex, &end_time);
+      if (res == ETIMEDOUT) {
+        woken = false;
+      } else if (res) {
+        tl::error << tr ("Error waiting for pthread Condition (timed)");
+      }
+
+    } else {
+
+      if (pthread_cond_wait (&m_cond, &m_mutex) != 0) {
+        tl::error << tr ("Error waiting for pthread Condition (timed)");
+      }
+
+    }
+
+    //  transfers the lock back
+    mutex->lock ();
+    pthread_mutex_unlock (&m_mutex);
+
+    return woken;
+  }
+
+  void wake_all ()
+  {
+    if (pthread_mutex_lock (&m_mutex) == 0) {
+      pthread_cond_broadcast (&m_cond);
+      pthread_mutex_unlock (&m_mutex);
+    }
+  }
+
+  void wake_one ()
+  {
+    if (pthread_mutex_lock (&m_mutex) == 0) {
+      pthread_cond_signal (&m_cond);
+      pthread_mutex_unlock (&m_mutex);
+    }
+  }
+
+private:
+  pthread_mutex_t m_mutex;
+  pthread_cond_t m_cond;
+  bool m_initialized;
+};
+
 WaitCondition::WaitCondition ()
 {
-  // @@@
+  mp_data = new WaitConditionPrivate ();
 }
 
-bool WaitCondition::wait (Mutex *mutex, unsigned long /*time*/)
+WaitCondition::~WaitCondition ()
 {
-  mutex->unlock();
-  // @@@
-  mutex->lock();
-  return true;
+  delete mp_data;
+  mp_data = 0;
+}
+
+bool WaitCondition::wait (Mutex *mutex, unsigned long time)
+{
+  return mp_data->wait (mutex, time);
 }
 
 void WaitCondition::wakeAll ()
 {
-  // @@@
+  mp_data->wake_all ();
 }
 
 void WaitCondition::wakeOne ()
 {
-  // @@@
+  mp_data->wake_one ();
 }
 
 // -------------------------------------------------------------------------------
diff --git a/src/tl/tl/tlThreads.h b/src/tl/tl/tlThreads.h
index 2d778172f..f8d88263e 100644
--- a/src/tl/tl/tlThreads.h
+++ b/src/tl/tl/tlThreads.h
@@ -86,14 +86,20 @@ public:
 
 #else
 
+class WaitConditionPrivate;
+
 //  The non-Qt version is a dummy implementation as threading is not supported (yet)
 class TL_PUBLIC WaitCondition
 {
 public:
   WaitCondition ();
+  ~WaitCondition ();
   bool wait (Mutex * /*mutex*/, unsigned long /*time*/ = std::numeric_limits<unsigned long>::max ());
   void wakeAll ();
   void wakeOne ();
+
+private:
+  WaitConditionPrivate *mp_data;
 };
 
 #endif
diff --git a/src/tl/unit_tests/tlThreads.cc b/src/tl/unit_tests/tlThreads.cc
index 05553bef1..5e41bb48d 100644
--- a/src/tl/unit_tests/tlThreads.cc
+++ b/src/tl/unit_tests/tlThreads.cc
@@ -258,6 +258,7 @@ public:
     while (m_value < 10000000) {
       m_value += s_mythread2_increment;
       if (m_value == m_nstop) {
+        tl::MutexLocker locker (&s_wait_mutex);
         m_stopped = true;
         s_condition.wait (&s_wait_mutex);
         m_stopped = false;
@@ -280,7 +281,15 @@ TEST(4_wakeAll)
   thr1.start ();
   thr2.start ();
 
-  while (! thr1.stopped () || ! thr2.stopped ()) {
+  while (true) {
+    bool res;
+    {
+      tl::MutexLocker locker (&s_wait_mutex);
+      res = thr1.stopped () && thr2.stopped ();
+    }
+    if (res) {
+      break;
+    }
     EXPECT_EQ (thr1.isRunning (), true);
     EXPECT_EQ (thr2.isRunning (), true);
     tl_assert (thr1.isRunning () && thr2.isRunning ());
@@ -305,7 +314,15 @@ TEST(4_wakeOne)
   thr1.start ();
   thr2.start ();
 
-  while (! thr1.stopped () || ! thr2.stopped ()) {
+  while (true) {
+    bool res;
+    {
+      tl::MutexLocker locker (&s_wait_mutex);
+      res = thr1.stopped () && thr2.stopped ();
+    }
+    if (res) {
+      break;
+    }
     EXPECT_EQ (thr1.isRunning (), true);
     EXPECT_EQ (thr2.isRunning (), true);
     tl_assert (thr1.isRunning () && thr2.isRunning ());