LXR qemu/include/sysemu/rtc.h

   1/*
   2 * RTC configuration and clock read
   3 *
   4 * Copyright (c) 2003-2021 QEMU contributors
   5 *
   6 * Permission is hereby granted, free of charge, to any person obtaining a copy
   7 * of this software and associated documentation files (the "Software"), to deal
   8 * in the Software without restriction, including without limitation the rights
   9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10 * copies of the Software, and to permit persons to whom the Software is
  11 * furnished to do so, subject to the following conditions:
  12 *
  13 * The above copyright notice and this permission notice shall be included in
  14 * all copies or substantial portions of the Software.
  15 *
  16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22 * THE SOFTWARE.
  23 */
  24
  25#ifndef SYSEMU_RTC_H
  26#define SYSEMU_RTC_H
  27
  28/**
  29 * qemu_get_timedate: Get the current RTC time
  30 * @tm: struct tm to fill in with RTC time
  31 * @offset: offset in seconds to adjust the RTC time by before
  32 *          converting to struct tm format.
  33 *
  34 * This function fills in @tm with the current RTC time, as adjusted
  35 * by @offset (for example, if @offset is 3600 then the returned time/date
  36 * will be one hour further ahead than the current RTC time).
  37 *
  38 * The usual use is by RTC device models, which should call this function
  39 * to find the time/date value that they should return to the guest
  40 * when it reads the RTC registers.
  41 *
  42 * The behaviour of the clock whose value this function returns will
  43 * depend on the -rtc command line option passed by the user.
  44 */
  45void qemu_get_timedate(struct tm *tm, int offset);
  46
  47/**
  48 * qemu_timedate_diff: Return difference between a struct tm and the RTC
  49 * @tm: struct tm containing the date/time to compare against
  50 *
  51 * Returns the difference in seconds between the RTC clock time
  52 * and the date/time specified in @tm. For example, if @tm specifies
  53 * a timestamp one hour further ahead than the current RTC time
  54 * then this function will return 3600.
  55 */
  56int qemu_timedate_diff(struct tm *tm);
  57
  58#endif
  59