glibc/io/sys/poll.h

/* Compatibility definitions for System V `poll' interface.
   Copyright (C) 1994-2019 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 Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef	_SYS_POLL_H
#define	_SYS_POLL_H	1

#include <features.h>

/* Get the platform dependent bits of `poll'.  */
#include <bits/poll.h>
#ifdef __USE_GNU
# include <bits/types/__sigset_t.h>
# include <bits/types/struct_timespec.h>
#endif


/* Type used for the number of file descriptors.  */
typedef unsigned long int nfds_t;

/* 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.  */
  };


__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.

   This function is a cancellation point and therefore not marked with
   __THROW.  */
extern int poll (struct pollfd *__fds, nfds_t __nfds, int __timeout);

#ifdef __USE_GNU
/* Like poll, but before waiting the threads signal mask is replaced
   with that specified in the fourth parameter.  For better usability,
   the timeout value is specified using a TIMESPEC object.

   This function is a cancellation point and therefore not marked with
   __THROW.  */
extern int ppoll (struct pollfd *__fds, nfds_t __nfds,
		  const struct timespec *__timeout,
		  const __sigset_t *__ss);
#endif

__END_DECLS


/* Define some inlines helping to catch common problems.  */
#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
# include <bits/poll2.h>
#endif

#endif	/* sys/poll.h */