Get FILETIME (Windows) value as of 1970-01-01T00:00:00Z

filetime_to_epoch.c

#include <windows.h>
#include <stdio.h>

int main()
{
    SYSTEMTIME st;
    FILETIME ft;
    ULARGE_INTEGER ulft;

    // 1970-01-01T00:00:00Z
    st.wYear = 1970;
    st.wMonth = 1;
    st.wDayOfWeek = 4;
    st.wDay = 1;
    st.wHour = 0;
    st.wMinute = 0;
    st.wSecond = 0;
    st.wMilliseconds = 0;

    if(!SystemTimeToFileTime(&st, &ft))
    {
        fprintf(stderr, "SystemTimeToFileTime() failed, GLE=%d\n", GetLastError());
        return 1;
    }

    ulft.HighPart = ft.dwHighDateTime;
    ulft.LowPart = ft.dwLowDateTime;

    printf("%llu", ulft.QuadPart);

    return 0;
}

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