1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #pragma once 30 31 /** 32 * @file sys/eventfd.h 33 * @brief Event notification file descriptors. 34 */ 35 36 #include <sys/cdefs.h> 37 #include <fcntl.h> 38 39 __BEGIN_DECLS 40 41 /** The eventfd() flag for a close-on-exec file descriptor. */ 42 #define EFD_CLOEXEC O_CLOEXEC 43 /** The eventfd() flag for a non-blocking file descriptor. */ 44 #define EFD_NONBLOCK O_NONBLOCK 45 46 /** 47 * [eventfd(2)](http://man7.org/linux/man-pages/man2/eventfd.2.html) creates a file descriptor 48 * for event notification. 49 * 50 * Returns a new file descriptor on success, and returns -1 and sets `errno` on failure. 51 */ 52 int eventfd(unsigned int __initial_value, int __flags); 53 54 /** The type used by eventfd_read() and eventfd_write(). */ 55 typedef uint64_t eventfd_t; 56 57 /** 58 * [eventfd_read(3)](http://man7.org/linux/man-pages/man2/eventfd.2.html) is a convenience 59 * wrapper to read an `eventfd_t` from an eventfd file descriptor. 60 * 61 * Returns 0 on success, or returns -1 otherwise. 62 */ 63 int eventfd_read(int __fd, eventfd_t* __value); 64 65 /** 66 * [eventfd_write(3)](http://man7.org/linux/man-pages/man2/eventfd.2.html) is a convenience 67 * wrapper to write an `eventfd_t` to an eventfd file descriptor. 68 * 69 * Returns 0 on success, or returns -1 otherwise. 70 */ 71 int eventfd_write(int __fd, eventfd_t __value); 72 73 __END_DECLS 74
