clock_lock       1179 src/dps8/dps8_scu.c static pthread_mutex_t clock_lock = PTHREAD_MUTEX_INITIALIZER;
clock_lock       1186 src/dps8/dps8_scu.c     pthread_mutex_lock (& clock_lock);
clock_lock       1311 src/dps8/dps8_scu.c     pthread_mutex_unlock (& clock_lock);