Win32 records file creation time, last access time and last write time for each file. The GetFileTime, FindFirstFile and FindNextFile functions return these times as FILETIME structures. This structure represents time as a number of 100-nanosecond intervals. This is a convenient way to represent time internally, but it is not a convenient way to display time to a user. The FileTimeToSystemTime function converts a FILETIME structure to a SYSTEMTIME structure containing individual members for the month, day, year, weekday, hour, minute, second and millisecond.
Writing to a file changes the last write time; reading from the file changes the last access time (this includes running an executable file). The SetFileTime function can be used to explicitly set the file times.