static char *begfield (int tab, char *ptr, char *lim, int sword, int schar){  if (tab)    {      while (ptr < lim && sword--)	{	  while (ptr < lim && *ptr != tab)	    ++ptr;	  if (ptr < lim)	    ++ptr;	}    }  else    {      while (1)	;    }  if (ptr + schar <= lim)    ptr += schar;  return ptr;}main (){  char *s = ":ab";  char *lim = s + 3;  if (begfield (':', s, lim, 1, 1) != s + 2)    abort ();  exit (0);}