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/* Compatibility definitions for System V `poll' interface.
Copyright (C) 1994 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., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#ifndef _SYS_POLL_H
#define _SYS_POLL_H
#include <sys/cdefs.h>
/* Data structure describing a polling request. */
struct pollfd
{
int fd; /* File descriptor to poll. */
short int events; /* Types of events poller cares about. */
short int revents; /* Types of events that actually occurred. */
};
/* Event types that can be polled for. These bits may be set in `events'
to indicate the interesting event types; they will appear in `revents'
to indicate the status of the file descriptor. */
#define POLLIN 01 /* There is data to read. */
#define POLLPRI 02 /* There is urgent data to read. */
#define POLLOUT 04 /* Writing now will not block. */
/* Event types always implicitly polled for. These bits need not be set in
`events', but they will appear in `revents' to indicate the status of
the file descriptor. */
#define POLLERR 010 /* Error condition. */
#define POLLHUP 020 /* Hung up. */
#define POLLNVAL 040 /* Invalid polling request. */
/* Canonical number of polling requests to read in at a time in poll. */
#define NPOLLFILE 30
__BEGIN_DECLS
/* Poll the file descriptors described by the NFDS structures starting at
FDS. If TIMEOUT is nonzero and not -1, allow TIMEOUT milliseconds for
an event to occur; if TIMEOUT is -1, block until an event occurs.
Returns the number of file descriptors with events, zero if timed out,
or -1 for errors. */
extern int poll __P ((struct pollfd *__fds, unsigned long int __nfds,
int __timeout));
__END_DECLS
#endif /* sys/poll.h */
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