This chapter groups functions used either for reporting on time (elapsed, current, or compute time) or to perform calculations based on time.

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.

Go to the first, previous, next, last section, table of contents.