[glibc.git] / io / sys / poll.h

/* Compatibility definitions for System V `poll' interface.
   Copyright (C) 1994, 1996 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_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.  */

/* Some aliases.  */
#define POLLWRNORM	POLLOUT

/* 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 */
Commit	Line	Data
28f540f4	1	/* Compatibility definitions for System V `poll' interface.
2c6fe0bd UD	2	Copyright (C) 1994, 1996 Free Software Foundation, Inc.
2c6fe0bd UD	3	This file is part of the GNU C Library.
28f540f4	4
2c6fe0bd UD	5	The GNU C Library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Library General Public License as
	7	published by the Free Software Foundation; either version 2 of the
	8	License, or (at your option) any later version.
28f540f4	9
2c6fe0bd UD	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Library General Public License for more details.
28f540f4	14
2c6fe0bd UD	15	You should have received a copy of the GNU Library General Public
	16	License along with the GNU C Library; see the file COPYING.LIB. If not,
	17	write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	18	Boston, MA 02111-1307, USA. */
28f540f4 RM	19
	20	#ifndef _SYS_POLL_H
	21	#define _SYS_POLL_H
	22
	23	#include <sys/cdefs.h>
	24
	25	/* Data structure describing a polling request. */
	26	struct pollfd
	27	{
	28	int fd; /* File descriptor to poll. */
	29	short int events; /* Types of events poller cares about. */
	30	short int revents; /* Types of events that actually occurred. */
	31	};
	32
	33	/* Event types that can be polled for. These bits may be set in `events'
	34	to indicate the interesting event types; they will appear in `revents'
	35	to indicate the status of the file descriptor. */
	36	#define POLLIN 01 /* There is data to read. */
	37	#define POLLPRI 02 /* There is urgent data to read. */
	38	#define POLLOUT 04 /* Writing now will not block. */
	39
2c6fe0bd UD	40	/* Some aliases. */
	41	#define POLLWRNORM POLLOUT
	42
28f540f4 RM	43	/* Event types always implicitly polled for. These bits need not be set in
	44	`events', but they will appear in `revents' to indicate the status of
	45	the file descriptor. */
	46	#define POLLERR 010 /* Error condition. */
	47	#define POLLHUP 020 /* Hung up. */
	48	#define POLLNVAL 040 /* Invalid polling request. */
	49
	50	/* Canonical number of polling requests to read in at a time in poll. */
	51	#define NPOLLFILE 30
	52
	53
	54	__BEGIN_DECLS
	55
	56	/* Poll the file descriptors described by the NFDS structures starting at
	57	FDS. If TIMEOUT is nonzero and not -1, allow TIMEOUT milliseconds for
	58	an event to occur; if TIMEOUT is -1, block until an event occurs.
	59	Returns the number of file descriptors with events, zero if timed out,
	60	or -1 for errors. */
	61
	62	extern int poll __P ((struct pollfd *__fds, unsigned long int __nfds,
	63	int __timeout));
	64
	65	__END_DECLS
	66
	67	#endif /* sys/poll.h */