Functions:

asctime	Convert tm structure to string
clock	Return number of clock ticks since process start
ctime	Convert time_t value to string
difftime	Return difference between two times
gmtime	Convert time_t value to tm structure as UTC time
localtime	Convert time_t value to tm structure as local time
mktime	Convert tm structure to time_t value
time	Get current time

Types and constants:

CLK_TCK

Constant that defines the number of clock ticks per second. Used by clock function.

clock_t and time_t

Data types returned by clock and time functions respectivelly. They are generally defined as long int.

tm

Structure returned or used by asctime, gmtime, localtime and mktime. See tm structure definition.