Web search results:

[1] "System Services Windows System Information Time Functions Article 01/07/2021 3 minutes to read 6 contributors Feedback The following functions are used with system time. The following functions are used with local time. The following functions are used with file time. The following functions are used with MS-DOS date and time."
URL: https://learn.microsoft.com/en-us/windows/win32/sysinfo/time-functions

[2] "First, the GetSystemTime* calls are the only Win32 APIs providing the systems time. This time has a fairly coarse granularity, as most applications do not need the overhead required to maintain a higher resolution. Time is (likely) stored internally as a 64-bit count of milliseconds. Calling timeGetTime gets the low order 32 bits."
URL: https://stackoverflow.com/questions/3729169/how-can-i-get-the-windows-system-time-with-millisecond-resolution

[3] "To get the system time, call the standard clock_gettime function. Set the system time To set the system time, call the standard clock_settime function. Synchronize the system time with the RTC When the system time is set, it does not persist when the device loses power. To persist the time during power loss, call the Applibs clock_systohc function."
URL: https://learn.microsoft.com/en-us/azure-sphere/app-development/rtc


Current date: 3/7/2023

Instructions: Using the provided web search results, write a comprehensive reply to the given query. Make sure to cite results using [[number](URL)] notation after the reference. If the provided search results refer to multiple subjects with the same name, write separate answers for each subject.
Query: Does Windows have API can write system time to rtc?
Yes, Windows has an API that can write the system time to the real-time clock (RTC). According to Microsoft's Learn platform, the Applibs clock_systohc function can be used to synchronize the system time with the RTC on an Azure Sphere device. This function takes the system time and writes it to the RTC, ensuring that the time persists during power loss.

However, it's important to note that this function is part of the Azure Sphere platform and is not available on standard Windows systems. For Windows systems, the GetSystemTime* calls can be used to retrieve the system time with a relatively coarse granularity, but there is no built-in API to write the system time to the RTC.

If the goal is to write the system time to the RTC on a standard Windows system, it may be necessary to use third-party software or hardware solutions that provide this functionality.

[[1](https://learn.microsoft.com/en-us/azure-sphere/app-development/rtc)]
[[2](https://learn.microsoft.com/en-us/windows/win32/sysinfo/time-functions)]
[[3](https://stackoverflow.com/questions/3729169/how-can-i-get-the-windows-system-time-with-millisecond-resolution)]