1 /* Copyright (C) 1997-2021 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 0x001 /* There is data to read. */ 26 #define POLLPRI 0x002 /* There is urgent data to read. */ 27 #define POLLOUT 0x004 /* Writing now will not block. */ 28 29 #if defined __USE_XOPEN || defined __USE_XOPEN2K8 30 /* These values are defined in XPG4.2. */ 31 # define POLLRDNORM 0x040 /* Normal data may be read. */ 32 # define POLLRDBAND 0x080 /* Priority data may be read. */ 33 # define POLLWRNORM POLLOUT /* Writing now will not block. */ 34 # define POLLWRBAND 0x100 /* Priority data may be written. */ 35 #endif 36 37 #ifdef __USE_GNU 38 /* These are extensions for Linux. */ 39 # define POLLMSG 0x200 40 # define POLLREMOVE 0x400 41 # define POLLRDHUP 0x800 42 #endif 43 44 /* Event types always implicitly polled for. These bits need not be set in 45 `events', but they will appear in `revents' to indicate the status of 46 the file descriptor. */ 47 #define POLLERR 0x008 /* Error condition. */ 48 #define POLLHUP 0x010 /* Hung up. */ 49 #define POLLNVAL 0x020 /* Invalid polling request. */