Table 7 Definitions in <time.h>

                     Macros
----------------------------------------------------
NULL
CLOCKS_PER_SEC

                     Types
----------------------------------------------------
size_t
clock_t          system clock type
time_t           ncoded time/date value
struct tm        decoded time/date components

                     Functions
----------------------------------------------------
difftime         duration between two times
mktime           normalizes a struct tm
time             retrieves current time encoding
asctime          text representation of a time value
ctime            text representation of current time
gmtime           decodes into UTC time
localtime        decodes a time value
strftime         formats a decoded time