I have been using the pj_lock_create_simple_mutex(..) for a while. As I understand it repeated calls to pj_lock_acquire(mutex_p) should result in a deadlock since the mutex is not recursive. This is not the case though and when looking at the pj_mutex code it seems as the "type " that identifies a simple or recursive mutex is never used. So I guess all mutexes are recursive as it is now? /Johan