The header file, time.h, defines three types. clock_t and time_t are both used for representations of time particularly suitable for arithmetic. (In this implementation, quantities of type, clock_t, have the highest resolution possible on your machine, and quantities of type, time_t, resolve to seconds.) size_t is also defined if necessary for quantities representing sizes.
time.h
also defines the structure, tm,
for the traditional representation of Gregorian calendar time as a series
of numbers, with the following fields.
| tm_sec | Seconds. |
| tm_min | Minutes. |
| tm_hour | Hours. |
| tm_mday | Day. |
| tm_mon | Month. |
| tm_year | Year (since 1900). |
| tm_wday | Day of week: the number of days since Sunday. |
| tm_yday | Number of days elapsed since last January 1. |
| tm_isdst | Daylight Savings Time flag: positive means DST in effect, zero means DST not in effect, negative means no information about DST is available. |