code.delx.au - pulseaudio/blob - src/pulsecore/poll.h

   1 /* $Id$ */
   2
   3 /***
   4    Compatibility definitions for System V `poll' interface.
   5    Copyright (C) 1994,96,97,98,99,2000,2001,2004 Free Software Foundation, Inc.
   6    Copyright (C) 2005, Cendio AB.
   7    This file is part of PulseAudio.
   8    Based on work for the GNU C Library.
   9 ***/
  10
  11 /***
  12   This file is part of PulseAudio.
  13
  14   PulseAudio is free software; you can redistribute it and/or modify
  15   it under the terms of the GNU Lesser General Public License as published
  16   by the Free Software Foundation; either version 2 of the License,
  17   or (at your option) any later version.
  18
  19   PulseAudio is distributed in the hope that it will be useful, but
  20   WITHOUT ANY WARRANTY; without even the implied warranty of
  21   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  22   General Public License for more details.
  23
  24   You should have received a copy of the GNU Lesser General Public License
  25   along with PulseAudio; if not, write to the Free Software
  26   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  27   USA.
  28 ***/
  29
  30 /* Event types that can be polled for.  These bits may be set in `events'
  31    to indicate the interesting event types; they will appear in `revents'
  32    to indicate the status of the file descriptor.  */
  33 #define POLLIN          0x001           /* There is data to read.  */
  34 #define POLLPRI         0x002           /* There is urgent data to read.  */
  35 #define POLLOUT         0x004           /* Writing now will not block.  */
  36
  37 /* Event types always implicitly polled for.  These bits need not be set in
  38    `events', but they will appear in `revents' to indicate the status of
  39    the file descriptor.  */
  40 #define POLLERR         0x008           /* Error condition.  */
  41 #define POLLHUP         0x010           /* Hung up.  */
  42 #define POLLNVAL        0x020           /* Invalid polling request.  */
  43
  44
  45 /* Type used for the number of file descriptors.  */
  46 typedef unsigned long int nfds_t;
  47
  48 /* Data structure describing a polling request.  */
  49 struct pollfd
  50   {
  51     int fd;                     /* File descriptor to poll.  */
  52     short int events;           /* Types of events poller cares about.  */
  53     short int revents;          /* Types of events that actually occurred.  */
  54   };
  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 extern int poll (struct pollfd *__fds, nfds_t __nfds, int __timeout);