io/sys/poll.h

   1 /* Compatibility definitions for System V `poll' interface.
   2    Copyright (C) 1994,1996-2001,2004,2005 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _SYS_POLL_H
  21 #define _SYS_POLL_H     1
  22
  23 #include <features.h>
  24
  25 /* Get the platform dependent bits of `poll'.  */
  26 #include <bits/poll.h>
  27
  28
  29 /* Type used for the number of file descriptors.  */
  30 typedef unsigned long int nfds_t;
  31
  32 /* Data structure describing a polling request.  */
  33 struct pollfd
  34   {
  35     int fd;                     /* File descriptor to poll.  */
  36     short int events;           /* Types of events poller cares about.  */
  37     short int revents;          /* Types of events that actually occurred.  */
  38   };
  39
  40
  41 __BEGIN_DECLS
  42
  43 /* Poll the file descriptors described by the NFDS structures starting at
  44    FDS.  If TIMEOUT is nonzero and not -1, allow TIMEOUT milliseconds for
  45    an event to occur; if TIMEOUT is -1, block until an event occurs.
  46    Returns the number of file descriptors with events, zero if timed out,
  47    or -1 for errors.
  48
  49    This function is a cancellation point and therefore not marked with
  50    __THROW.  */
  51 extern int poll (struct pollfd *__fds, nfds_t __nfds, int __timeout);
  52
  53 __END_DECLS
  54
  55 #endif  /* sys/poll.h */