# org.freedesktop.timedate1

## NAME



           org.freedesktop.timedate1 - The D-Bus interface of
           systemd-timedated
    


## INTRODUCTION



           systemd-timedated.service(8) is a system service that can be used
           to control the system time and related settings. This page
           describes the D-Bus interface.
    


## THE D-BUS API



           The service exposes the following interfaces on the bus:
    
               node /org/freedesktop/timedate1 {
                 interface org.freedesktop.timedate1 {
                   methods:
                     SetTime(in  x usec_utc,
                             in  b relative,
                             in  b interactive);
                     SetTimezone(in  s timezone,
                                 in  b interactive);
                     SetLocalRTC(in  b local_rtc,
                                 in  b fix_system,
                                 in  b interactive);
                     SetNTP(in  b use_ntp,
                            in  b interactive);
                     ListTimezones(out as timezones);
                   properties:
                     readonly s Timezone = '...';
                     readonly b LocalRTC = ...;
                     @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                     readonly b CanNTP = ...;
                     readonly b NTP = ...;
                     @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                     readonly b NTPSynchronized = ...;
                     @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                     readonly t TimeUSec = ...;
                     @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                     readonly t RTCTimeUSec = ...;
                 };
                 interface org.freedesktop.DBus.Peer { ... };
                 interface org.freedesktop.DBus.Introspectable { ... };
                 interface org.freedesktop.DBus.Properties { ... };
               };
    
       **Methods**
           Use **SetTime()** to change the system clock. Pass a value of
           microseconds since the UNIX epoch (1 Jan 1970 UTC). If _relative_ is
           true, the passed usec value will be added to the current system
           time. If it is false, the current system time will be set to the
           passed usec value. If the system time is set with this method, the
           RTC will be updated as well.
    
           Use **SetTimezone()** to set the system timezone. Pass a value like
           "Europe/Berlin" to set the timezone. Valid timezones are listed in
           /usr/share/zoneinfo/zone.tab. If the RTC is configured to be
           maintained in local time, it will be updated accordingly.
    
           Use **SetLocalRTC()** to control whether the RTC is in local time or
           UTC. It is strongly recommended to maintain the RTC in UTC.
           However, some OSes (Windows) maintain the RTC in local time, which
           might make it necessary to enable this feature. Note that this
           might create various problems as daylight changes could be missed.
           If _fix_system_ is "true", the time from the RTC is read again and
           the system clock is adjusted according to the new setting. If
           _fix_system_ is "false", the system time is written to the RTC
           taking the new setting into account. Use _fix_system=true_ in
           installers and livecds where the RTC is probably more reliable
           than the system time. Use _fix_system=false_ in configuration UIs
           that are run during normal operation and where the system clock is
           probably more reliable than the RTC.
    
           Use **SetNTP()** to control whether the system clock is synchronized
           with the network using systemd-timesyncd. This will enable and
           start or disable and stop the chosen time synchronization service.
    
           **ListTimezones()** returns a list of time zones known on the local
           system as an array of names ("["Africa/Abidjan", "Africa/Accra",
           ..., "UTC"]").
    
       **Properties**
           _Timezone_ shows the currently configured time zone.  _LocalRTC_ shows
           whether the RTC is configured to use UTC (false), or the local
           time zone (true).  _CanNTP_ shows whether a service to perform time
           synchronization over the network is available, and _NTP_ shows
           whether such a service is enabled.
    
           _NTPSynchronized_ shows whether the kernel reports the time as
           synchronized (c.f.  **adjtimex**(3)).  _TimeUSec_ and _RTCTimeUSec_ show
           the current time on the system and in the RTC. The purpose of
           those three properties is to allow remote clients to access this
           information over D-Bus. Local clients can access the information
           directly.
    
           Whenever the _Timezone_ and _LocalRTC_ settings are changed via the
           daemon, **PropertyChanged** signals are sent out to clients which have
           subscribed.
    
           Note that this service will not inform you about system time
           changes. Use **timerfd**(3) with **CLOCK_REALTIME** and
           **TFD_TIMER_CANCEL_ON_SET** for that.
    
       **Security**
           The _interactive_ boolean parameters can be used to control whether
           **polkit******[1] should interactively ask the user for authentication
           credentials if required.
    
           The polkit action for**SetTimezone()** is
           org.freedesktop.timedate1.set-timezone. For **SetLocalRTC()** it is
           org.freedesktop.timedate1.set-local-rtc, for **SetTime()** it is
           org.freedesktop.timedate1.set-time and for **SetNTP()** it is
           org.freedesktop.timedate1.set-ntp.  **ListTimezones()** does not
           require any privileges.
    


## EXAMPLES



           **Example 1. Introspect org.freedesktop.timedate1 on the bus**
    
               $ gdbus introspect --system \
                 --dest org.freedesktop.timedate1 \
                 --object-path /org/freedesktop/timedate1
    


## VERSIONING



           These D-Bus interfaces follow **the usual interface versioning**
           **guidelines******[2].


## NOTES



            1. polkit
               https://www.freedesktop.org/software/polkit/docs/latest/
    
            2. the usual interface versioning guidelines
               https://0pointer.de/blog/projects/versioning-dbus.html
    
            3. More information on how the system clock and RTC interact
               https://lists.freedesktop.org/archives/systemd-devel/2011-May/002526.html
    


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