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

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   5
   6   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
   7
   8   PulseAudio is free software; you can redistribute it and/or modify
   9   it under the terms of the GNU Lesser General Public License as published
  10   by the Free Software Foundation; either version 2 of the License,
  11   or (at your option) any later version.
  12
  13   PulseAudio is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with PulseAudio; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21   USA.
  22 ***/
  23
  24 /***
  25    Based on work for the GNU C Library.
  26    Copyright (C) 1994,96,97,98,99,2000,2001,2004 Free Software Foundation, Inc.
  27 ***/
  28
  29 /* Event types that can be polled for.  These bits may be set in `events'
  30    to indicate the interesting event types; they will appear in `revents'
  31    to indicate the status of the file descriptor.  */
  32 #define POLLIN          0x001           /* There is data to read.  */
  33 #define POLLPRI         0x002           /* There is urgent data to read.  */
  34 #define POLLOUT         0x004           /* Writing now will not block.  */
  35
  36 /* Event types always implicitly polled for.  These bits need not be set in
  37    `events', but they will appear in `revents' to indicate the status of
  38    the file descriptor.  */
  39 #define POLLERR         0x008           /* Error condition.  */
  40 #define POLLHUP         0x010           /* Hung up.  */
  41 #define POLLNVAL        0x020           /* Invalid polling request.  */
  42
  43
  44 /* Type used for the number of file descriptors.  */
  45 typedef unsigned long int nfds_t;
  46
  47 /* Data structure describing a polling request.  */
  48 struct pollfd
  49   {
  50     int fd;                     /* File descriptor to poll.  */
  51     short int events;           /* Types of events poller cares about.  */
  52     short int revents;          /* Types of events that actually occurred.  */
  53   };
  54
  55 /* Poll the file descriptors described by the NFDS structures starting at
  56    FDS.  If TIMEOUT is nonzero and not -1, allow TIMEOUT milliseconds for
  57    an event to occur; if TIMEOUT is -1, block until an event occurs.
  58    Returns the number of file descriptors with events, zero if timed out,
  59    or -1 for errors.  */
  60 extern int poll (struct pollfd *__fds, nfds_t __nfds, int __timeout);