io/sys/poll.h

   1 /* Compatibility definitions for System V `poll' interface.
   2    Copyright (C) 1994-2014 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _SYS_POLL_H
  20 #define _SYS_POLL_H     1
  21
  22 #include <features.h>
  23
  24 /* Get the platform dependent bits of `poll'.  */
  25 #include <bits/poll.h>
  26 #ifdef __USE_GNU
  27 /* Get the __sigset_t definition.  */
  28 # include <bits/sigset.h>
  29 /* Get the timespec definition.  */
  30 # define __need_timespec
  31 # include <time.h>
  32 #endif
  33
  34
  35 /* Type used for the number of file descriptors.  */
  36 typedef unsigned long int nfds_t;
  37
  38 /* Data structure describing a polling request.  */
  39 struct pollfd
  40   {
  41     int fd;                     /* File descriptor to poll.  */
  42     short int events;           /* Types of events poller cares about.  */
  43     short int revents;          /* Types of events that actually occurred.  */
  44   };
  45
  46
  47 __BEGIN_DECLS
  48
  49 /* Poll the file descriptors described by the NFDS structures starting at
  50    FDS.  If TIMEOUT is nonzero and not -1, allow TIMEOUT milliseconds for
  51    an event to occur; if TIMEOUT is -1, block until an event occurs.
  52    Returns the number of file descriptors with events, zero if timed out,
  53    or -1 for errors.
  54
  55    This function is a cancellation point and therefore not marked with
  56    __THROW.  */
  57 extern int poll (struct pollfd *__fds, nfds_t __nfds, int __timeout);
  58
  59 #ifdef __USE_GNU
  60 /* Like poll, but before waiting the threads signal mask is replaced
  61    with that specified in the fourth parameter.  For better usability,
  62    the timeout value is specified using a TIMESPEC object.
  63
  64    This function is a cancellation point and therefore not marked with
  65    __THROW.  */
  66 extern int ppoll (struct pollfd *__fds, nfds_t __nfds,
  67                   const struct timespec *__timeout,
  68                   const __sigset_t *__ss);
  69 #endif
  70
  71 __END_DECLS
  72
  73
  74 /* Define some inlines helping to catch common problems.  */
  75 #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
  76 # include <bits/poll2.h>
  77 #endif
  78
  79 #endif  /* sys/poll.h */