glibc/bits/select.h

/* Copyright (C) 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#ifndef _SYS_SELECT_H
#error "Never use <bits/select.h> directly; include <sys/select.h> instead."
#endif


/* We don't use `memset' because this would require a prototype and
   the array isn't too big.  */
#define __FD_ZERO(set) \
  do {									      \
    unsigned int __i;							      \
    __fd_mask *__arr = (set);						      \
    for (__i = 0; __i < sizeof (__fd_set) / sizeof (__fd_mask); ++__i)	      \
      __arr->fds_bits[__i] = '\0';					      \
  } while (0)
#define __FD_SET(d, set)	((set)->fds_bits[__FDELT(d)] |= __FDMASK(d))
#define __FD_CLR(d, set)	((set)->fds_bits[__FDELT(d)] &= ~__FDMASK(d))
#define __FD_ISSET(d, set)	((set)->fds_bits[__FDELT(d)] & __FDMASK(d))