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 <sys/cdefs.h> 37 38 #include <fcntl.h> 39 #include <linux/timerfd.h> 40 #include <time.h> 41 #include <sys/types.h> 42 43 __BEGIN_DECLS 44 45 /*! \macro TFD_CLOEXEC 46 * The timerfd_create() flag for a close-on-exec file descriptor. 47 */ 48 /*! \macro TFD_NONBLOCK 49 * The timerfd_create() flag for a non-blocking file descriptor. 50 */ 51 52 /** 53 * [timerfd_create(2)](https://man7.org/linux/man-pages/man2/timerfd_create.2.html) creates a 54 * timer file descriptor. 55 * 56 * Returns the new file descriptor on success, and returns -1 and sets `errno` on failure. 57 */ 58 int timerfd_create(clockid_t __clock, int __flags); 59 60 /** The timerfd_settime() flag to use absolute rather than relative times. */ 61 #define TFD_TIMER_ABSTIME (1 << 0) 62 /** The timerfd_settime() flag to cancel an absolute timer if the realtime clock changes. */ 63 #define TFD_TIMER_CANCEL_ON_SET (1 << 1) 64 65 /** 66 * [timerfd_settime(2)](https://man7.org/linux/man-pages/man2/timerfd_settime.2.html) starts or 67 * stops a timer. 68 * 69 * Returns 0 on success, and returns -1 and sets `errno` on failure. 70 */ 71 int timerfd_settime(int __fd, int __flags, const struct itimerspec* _Nonnull __new_value, struct itimerspec* _Nullable __old_value); 72 73 /** 74 * [timerfd_gettime(2)](https://man7.org/linux/man-pages/man2/timerfd_gettime.2.html) queries the 75 * current timer settings. 76 * 77 * Returns 0 on success, and returns -1 and sets `errno` on failure. 78 */ 79 int timerfd_gettime(int __fd, struct itimerspec* _Nonnull __current_value); 80 81 __END_DECLS 82