To set the file times for a file, use the SetFileTime function. When writing to a file, the last write time is not fully updated until all handles that are used for writing are closed. These functions copy the file times to FILETIME structures in a WIN32_FIND_DATA structure. You can also retrieve file times using the FindFirstFile and FindNextFile functions. GetFileTime copies the creation, last access, and last write times to individual FILETIME structures. To retrieve the file times for a specified file, use the GetFileTime function. The NTFS file system delays updates to the last access time for a file by up to 1 hour after the last access. For example, the resolution of create time on FAT is 10 milliseconds, while write time has a resolution of 2 seconds and access time has a resolution of 1 day, so it is really the access date. Not all file systems can record creation and last access times, and not all file systems record them in the same manner. The only guarantee about a file time stamp is that the file time is correctly reflected when the handle that makes the change is closed. Time stamps are updated at various times and for various reasons.
For example, a file that is saved at 3:00pm PST in Washington is seen as 6:00pm EST in New York on an NTFS volume, but it is seen as 3:00pm EST in New York on a FAT volume. The FAT file system stores time values based on the local time of the computer. The NTFS file system stores time values in UTC format, so they are not affected by changes in time zone or daylight saving time. The system records file times when applications create, access, and write to files. A file time is a 64-bit value that represents the number of 100-nanosecond intervals that have elapsed since 12:00 A.M.
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