io/sys/poll.h

   1 /* Compatibility definitions for System V `poll' interface.
   2    Copyright (C) 1994-2017 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 # include <bits/types/__sigset_t.h>
  28 # include <bits/types/struct_timespec.h>
  29 #endif
  30
  31
  32 /* Type used for the number of file descriptors.  */
  33 typedef unsigned long int nfds_t;
  34
  35 /* Data structure describing a polling request.  */
  36 struct pollfd
  37   {
  38     int fd;                     /* File descriptor to poll.  */
  39     short int events;           /* Types of events poller cares about.  */
  40     short int revents;          /* Types of events that actually occurred.  */
  41   };
  42
  43
  44 __BEGIN_DECLS
  45
  46 /* Poll the file descriptors described by the NFDS structures starting at
  47    FDS.  If TIMEOUT is nonzero and not -1, allow TIMEOUT milliseconds for
  48    an event to occur; if TIMEOUT is -1, block until an event occurs.
  49    Returns the number of file descriptors with events, zero if timed out,
  50    or -1 for errors.
  51
  52    This function is a cancellation point and therefore not marked with
  53    __THROW.  */
  54 extern int poll (struct pollfd *__fds, nfds_t __nfds, int __timeout);
  55
  56 #ifdef __USE_GNU
  57 /* Like poll, but before waiting the threads signal mask is replaced
  58    with that specified in the fourth parameter.  For better usability,
  59    the timeout value is specified using a TIMESPEC object.
  60
  61    This function is a cancellation point and therefore not marked with
  62    __THROW.  */
  63 extern int ppoll (struct pollfd *__fds, nfds_t __nfds,
  64                   const struct timespec *__timeout,
  65                   const __sigset_t *__ss);
  66 #endif
  67
  68 __END_DECLS
  69
  70
  71 /* Define some inlines helping to catch common problems.  */
  72 #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
  73 # include <bits/poll2.h>
  74 #endif
  75
  76 #endif  /* sys/poll.h */