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/* $Header: /var/lib/cvsd/repos/research/researchv9/X11/src/X.V11R1/lib/oldXtk/fd.h,v 1.1.1.1 2018/04/24 17:22:00 root Exp $ */
/*
 * Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.
 * 
 *                         All Rights Reserved
 * 
 * Permission to use, copy, modify, and distribute this software and its 
 * documentation for any purpose and without fee is hereby granted, 
 * provided that the above copyright notice appear in all copies and that
 * both that copyright notice and this permission notice appear in 
 * supporting documentation, and that the name of Digital Equipment
 * Corporation not be used in advertising or publicity pertaining to
 * distribution of the software without specific, written prior permission.  
 * 
 * 
 * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
 * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
 * DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
 * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
 * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

#ifndef __fd_set
#define __fd_set
#ifndef NBBY
#define	NBBY	8		/* number of bits in a byte */
#endif
/*
 * Select uses bit masks of file descriptors in longs.
 * These macros manipulate such bit fields (the filesystem macros use chars).
 * FD_SETSIZE may be defined by the user, but the default here
 * should be >= NOFILE (param.h).
 */
#ifndef	FD_SETSIZE
#define	FD_SETSIZE	256
#endif

typedef long	fd_mask;
#define NFDBITS	(sizeof(fd_mask) * NBBY)	/* bits per mask */
#ifndef howmany
#define	howmany(x, y)	(((x)+((y)-1))/(y))
#endif

typedef	struct Fd_set {
	fd_mask	fds_bits[howmany(FD_SETSIZE, NFDBITS)];
} Fd_set;

#define	FD_SET(n, p)	((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
#define	FD_CLR(n, p)	((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
#define	FD_ISSET(n, p)	((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))

#endif

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