V8.4_and_Higher

   The following additional functions are available on OpenVMS Alpha
   and Integrity servers Version 8.4 and higher:

   ftok              sem_init
   semctl            sem_open
   semget            sem_post
   semop             sem_timedwait
   sem_close         sem_trywait
   sem_destroy       sem_unlink
   sem_getvalue      sem_wait