anchor.diff:                           (#1 != Cnil) ? &tv : NULL);
   
             if (count == 0)
  -            @(return) = Cnil;
  +            @(return 0) = Cnil;
  +            @(return 1) = Cnil;
             else if (count < 0)
               /*###FIXME: We should be raising an error here...
   
                 except, ofcourse in case of EINTR or EAGAIN */
   
  -            @(return) = Cnil;
  +            @(return 0) = Cnil;
  +            @(return 1) = MAKE_INTEGER(errno);
             else
               {
                 cl_object rv = Cnil;
  
positive.code:           (secs usecs)
            (split-timeout (or timeout 1))
          (let* ((sock-fds (mapcar #'sb-bsd-sockets:socket-file-descriptor
                                   (mapcar #'socket sockets)))
                 (result-fds (read-select sock-fds (when timeout secs) usecs)))
            (remove-if #'(lambda (s)
                           (not
                            (member
                             (sb-bsd-sockets:socket-file-descriptor (socket s))
                             result-fds)))
                     sockets)))))
    )
  
negative.code: 
                  cur_fd = cur_fd->cons.cdr;
                }
                @(return 0) = rv;
                @(return 1) = Cnil;
              }
  }"))
  
  