I posted this problem also in the mango forum. But now i think it is perhaps a phobos problem: http://www.dsource.org/forums/viewtopic.php?t=1347 I get this assertion: pthread_mutex_lock.c:108: __pthread_mutex_lock: Assertion `mutex->__data.__owner == 0' failed. Can someone help? Frank -- D goes real-time: http://www.drealtime.com