convert Windows SYSTEMTIME to a string or char buf in C++ with user's "Region and Language" format?

To convert a SYSTEMTIME structure to a string or character buffer in C++ using the user's "Region and Language" format, you can use the GetDateFormat and GetTimeFormat functions from the Windows API. These functions allow you to format date and time values according to the user's locale settings.

Here's an example of how you can convert a SYSTEMTIME to a string:

cppCopy code
#include <Windows.h>

#include <iostream>

#include <string>



std::wstring SystemTimeToString(const SYSTEMTIME& sysTime)

{

    wchar_t buffer[255] = { 0 };

    int size = GetDateFormatW(LOCALE_USER_DEFAULT, 0, &sysTime, nullptr, buffer, sizeof(buffer) / sizeof(buffer[0]));

    if (size > 0)

    {

        std::wstring dateString(buffer, size - 1);  // Remove null terminator

        size = GetTimeFormatW(LOCALE_USER_DEFAULT, 0, &sysTime, nullptr, buffer, sizeof(buffer) / sizeof(buffer[0]));

        if (size > 0)

        {

            std::wstring timeString(buffer, size - 1);  // Remove null terminator

            return dateString + L" " + timeString;

        }

    }

    return L"";

}



int main()

{

    SYSTEMTIME sysTime;

    GetSystemTime(&sysTime);  // Example: Use current system time



    std::wstring dateTimeString = SystemTimeToString(sysTime);

    std::wcout << dateTimeString << std::endl;



    return 0;

}

This code retrieves the current system time using GetSystemTime and converts it to a string representation using GetDateFormat and GetTimeFormat with the LOCALE_USER_DEFAULT flag. The resulting string includes both the date and time in the user's desired format.

Note that you may need to adjust the code if you are working with a different SYSTEMTIME or need to specify a specific time value.

Make sure to include the necessary headers (<Windows.h> in this case) and handle any error cases that may arise during the conversion process.