step *stp;
stp = ws->step;
trace(TRACE_gc|DEBUG_gc, "push todo block %p (%ld words), step %d, n_todos: %d",
- bd->start, bd->free - bd->u.scan, stp->abs_no, stp->n_todos);
+ bd->start, (unsigned long)(bd->free - bd->u.scan),
+ stp->abs_no, stp->n_todos);
// ToDo: use buffer_todo
ACQUIRE_SPIN_LOCK(&stp->sync_todo);
if (stp->todos_last == NULL) {