mutex_alloc      4327 thread.c           return TypedData_Wrap_Struct(klass, &thread_shield_data_type, (void *)mutex_alloc(0));
mutex_alloc       120 thread_sync.c      return mutex_alloc(rb_cMutex);
mutex_alloc      1241 thread_sync.c      rb_define_alloc_func(rb_cMutex, mutex_alloc);