1 /* 2 * Copyright (C) 2013 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/timerfd.h 33 * @brief Timer file descriptors. 34 */ 35 36 #include <fcntl.h> /* For O_CLOEXEC and O_NONBLOCK. */ 37 #include <time.h> 38 #include <sys/cdefs.h> 39 #include <sys/types.h> 40 41 __BEGIN_DECLS 42 43 /** The timerfd_create() flag for a close-on-exec file descriptor. */ 44 #define TFD_CLOEXEC O_CLOEXEC 45 /** The timerfd_create() flag for a non-blocking file descriptor. */ 46 #define TFD_NONBLOCK O_NONBLOCK 47 48 /** 49 * [timerfd_create(2)](http://man7.org/linux/man-pages/man2/timerfd_create.2.html) creates a 50 * timer file descriptor. 51 * 52 * Returns the new file descriptor on success, and returns -1 and sets `errno` on failure. 53 */ 54 int timerfd_create(clockid_t __clock, int __flags); 55 56 /** The timerfd_settime() flag to use absolute rather than relative times. */ 57 #define TFD_TIMER_ABSTIME (1 << 0) 58 /** The timerfd_settime() flag to cancel an absolute timer if the realtime clock changes. */ 59 #define TFD_TIMER_CANCEL_ON_SET (1 << 1) 60 61 /** 62 * [timerfd_settime(2)](http://man7.org/linux/man-pages/man2/timerfd_settime.2.html) starts or 63 * stops a timer. 64 * 65 * Returns 0 on success, and returns -1 and sets `errno` on failure. 66 */ 67 int timerfd_settime(int __fd, int __flags, const struct itimerspec* _Nonnull __new_value, struct itimerspec* _Nullable __old_value); 68 69 /** 70 * [timerfd_gettime(2)](http://man7.org/linux/man-pages/man2/timerfd_gettime.2.html) queries the 71 * current timer settings. 72 * 73 * Returns 0 on success, and returns -1 and sets `errno` on failure. 74 */ 75 int timerfd_gettime(int __fd, struct itimerspec* _Nonnull __current_value); 76 77 __END_DECLS 78