Function sigwait

mysys/my_pthread.c:170–206

int sigwait(sigset_t *setp, int *sigp)
{
  if (memcmp(setp,&sigwait_set,sizeof(sigwait_set)))
    sigwait_setup(setp);			/* Init or change of set */

  for (;;)
  {
    /*
      This is a fast, not 100% portable implementation to find the signal.
      Because the handler is blocked there should be at most 1 bit set, but
      the specification on this is somewhat shady so we use a set instead a
      single variable.
      */

    ulong *ptr= (ulong*) &px_recd;
    ulong *end=ptr+sizeof(px_recd)/sizeof(ulong);

    for ( ; ptr != end ; ptr++)
    {
      if (*ptr)
      {
	ulong set= *ptr;
	int found= (int) ((char*) ptr - (char*) &px_recd)*8+1;
	while (!(set & 1))
	{
	  found++;
	  set>>=1;
	}
	*sigp=found;
	sigdelset(&px_recd,found);
	return 0;
      }
    }
    sigsuspend(&rev_sigwait_set);
  }
  return 0;
}
#else  /* !DONT_USE_SIGSUSPEND */

/****************************************************************************