hpux man page for clock

clock(3C)																 clock(3C)

NAME
       clock() - report CPU time used

SYNOPSIS
DESCRIPTION
       returns	the amount of CPU time (in microseconds) used since the first call to The time reported is the sum of the user and system times of
       the calling process and its terminated child processes for which it has executed , or (see wait(2) , system(3S), and popen(3S)).  To deter-
       mine the time in seconds, the value returned by should be divided by the value of the macro

       The resolution of the clock varies, depending on the hardware and on software configuration.

       If the processor time used is not available or its value cannot be represented, the function returns the value

WARNINGS
       The  value returned by is defined in microseconds for compatibility with systems that have CPU clocks with much higher resolution.  Because
       of this, the value returned wraps around after accumulating only 4295 seconds of CPU time (about 72 minutes).

DEPENDENCIES
       The default clock resolution is 10 milliseconds.

SEE ALSO
       times(2), wait(2), system(3S), thread_safety(5).

STANDARDS CONFORMANCE
																	 clock(3C)