Hi, I write the following code Int main() { omni_mutex mu; mu.lock(); exit(0); } Then I would get coredump by receive signal abort() It seems that I must call mu.unlock() before I exit in order to prevent the happening of coredump. Is this the designed behaviour and what can I do to prevent. My machine is HP-UX 11 and using aCC 3.5 Regards, Gao Yan