while (--this >= 0)
while (--this >= 1)
__sigwait (const sigset_t *set, int *sig){  sigset_t tmp_mask;  struct sigaction saved[NSIG];  struct sigaction action;  int save_errno;  int this;  /* Prepare set.  */  __sigfillset (&tmp_mask);  /* Unblock all signals in the SET and register our nice handler.  */  action.sa_handler = ignore_signal;  action.sa_flags = 0;  __sigfillset (&action.sa_mask);	/* Block all signals for handler.  */  /* Make sure we recognize error conditions by setting WAS_SIG to a     value which does not describe a legal signal number.  */  was_sig = -1;  for (this = 0; this < NSIG; ++this)    if (__sigismember (set, this))      {	/* Unblock this signal.  */	__sigdelset (&tmp_mask, this);	/* Register temporary action handler.  */	if (__sigaction (this, &action, &saved[this]) != 0)	  goto restore_handler;      }  /* Now we can wait for signals.  */  __sigsuspend (&tmp_mask); restore_handler:  save_errno = errno;  while (--this >= 0)    if (__sigismember (set, this))      /* We ignore errors here since we must restore all handlers.  */      __sigaction (this, &saved[this], NULL);  __set_errno (save_errno);  /* Store the result and return.  */  *sig = was_sig;  return was_sig == -1 ? -1 : 0;}