The Win32 API supports five time formats. Time-related functions return time in one of these formats. The Win32 API includes functions to convert between time formats for ease of comparison and display. The Win32 API also provides functions to convert certain time formats based on the time zone. The following table summarizes the time formats.
| Format | Type | Description |
|---|---|---|
| System | SYSTEMTIME | Year, month, day, hour, second, and millisecond, taken from the internal hardware clock. |
| File | FILETIME | 100-nanosecond intervals since January 1, 1601. |
| Local | SYSTEMTIME or FILETIME | A system time or file time converted to the system's local time zone. |
| MS-DOS | WORD | A packed 16-bit word for the date, another for the time. |
| Windows | DWORD | The number of milliseconds since the system booted; a quantity that cycles every 49.7 days. |
For more information, see the following topics.