exception descriptor

From: Tzung-Yu Wen (tywen@csie.nctu.edu.tw)
Date: 06/07/94


	A question about programmming skill....

	in comm.c, after using select() to select a descriptor,
	why do we need to check if exception descriptor is set?
	When will the exception descriptor be set? Can anyone
	give me an example? Thanks.

comm.c:
      if (select(maxdesc + 1, &input_set, &output_set, &exc_set, &null_time)
           < 0) {
         perror("Select poll");
         return;
      }
	....

      /* kick out the freaky folks */
      for (point = descriptor_list; point; point = next_point) {
         next_point = point->next;
         if (FD_ISSET(point->descriptor, &exc_set)) {
            FD_CLR(point->descriptor, &input_set);
            FD_CLR(point->descriptor, &output_set);
            close_socket(point);
         }
      }

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 E-mail Address: tywen@csie.nctu.edu.tw



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