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qemu/include/sysemu/rtc.h

59 lines
2.4 KiB
C

/*
* RTC configuration and clock read
*
* Copyright (c) 2003-2021 QEMU contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef SYSEMU_RTC_H
#define SYSEMU_RTC_H
/**
* qemu_get_timedate: Get the current RTC time
* @tm: struct tm to fill in with RTC time
* @offset: offset in seconds to adjust the RTC time by before
* converting to struct tm format.
*
* This function fills in @tm with the current RTC time, as adjusted
* by @offset (for example, if @offset is 3600 then the returned time/date
* will be one hour further ahead than the current RTC time).
*
* The usual use is by RTC device models, which should call this function
* to find the time/date value that they should return to the guest
* when it reads the RTC registers.
*
* The behaviour of the clock whose value this function returns will
* depend on the -rtc command line option passed by the user.
*/
void qemu_get_timedate(struct tm *tm, int offset);
/**
* qemu_timedate_diff: Return difference between a struct tm and the RTC
* @tm: struct tm containing the date/time to compare against
*
* Returns the difference in seconds between the RTC clock time
* and the date/time specified in @tm. For example, if @tm specifies
* a timestamp one hour further ahead than the current RTC time
* then this function will return 3600.
*/
int qemu_timedate_diff(struct tm *tm);
#endif