bits/poll.h

   1 /* Copyright (C) 1997-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _SYS_POLL_H
  19 # error "Never use <bits/poll.h> directly; include <sys/poll.h> instead."
  20 #endif
  21
  22 /* Event types that can be polled for.  These bits may be set in `events'
  23    to indicate the interesting event types; they will appear in `revents'
  24    to indicate the status of the file descriptor.  */
  25 #define POLLIN          01              /* There is data to read.  */
  26 #define POLLPRI         02              /* There is urgent data to read.  */
  27 #define POLLOUT         04              /* Writing now will not block.  */
  28
  29 #if defined __USE_XOPEN || defined __USE_XOPEN2K8
  30 /* These values are defined in XPG4.2 and later.  */
  31 # define POLLRDNORM     POLLIN          /* Normal data may be read.  */
  32 # define POLLRDBAND     POLLPRI         /* Priority data may be read.  */
  33 # define POLLWRNORM     POLLOUT         /* Writing now will not block.  */
  34 # define POLLWRBAND     POLLOUT         /* Priority data may be written.  */
  35 #endif
  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         010             /* Error condition.  */
  41 #define POLLHUP         020             /* Hung up.  */
  42 #define POLLNVAL        040             /* Invalid polling request.  */