bits/select.h

   1 /* Copyright (C) 1997, 1998, 2001, 2011 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #ifndef _SYS_SELECT_H
  20 # error "Never use <bits/select.h> directly; include <sys/select.h> instead."
  21 #endif
  22
  23
  24 /* We don't use `memset' because this would require a prototype and
  25    the array isn't too big.  */
  26 #define __FD_ZERO(s) \
  27   do {                                                                        \
  28     unsigned int __i;                                                         \
  29     fd_set *__arr = (s);                                                      \
  30     for (__i = 0; __i < sizeof (fd_set) / sizeof (__fd_mask); ++__i)          \
  31       __FDS_BITS (__arr)[__i] = 0;                                            \
  32   } while (0)
  33 #define __FD_SET(d, s) \
  34   ((void) (__FDS_BITS (s)[__FD_ELT(d)] |= __FD_MASK(d)))
  35 #define __FD_CLR(d, s) \
  36   ((void) (__FDS_BITS (s)[__FD_ELT(d)] &= ~__FD_MASK(d)))
  37 #define __FD_ISSET(d, s) \
  38   ((__FDS_BITS (s)[__FD_ELT (d)] & __FD_MASK (d)) != 0)