CLOCK

clock ? Determine processor time

#include <time.h>

clock_t clock(void);

The clock() function returns an approximation of processor time used by the program.

The value returned is the CPU time used so far as a clock_t; to get the number of seconds used, divide by CLOCKS_PER_SEC.

ANSI C. POSIX requires that CLOCKS_PER_SEC equals 1000000 independent of the actual resolution.

The C standard allows for arbitrary values at the start of the program; take the difference between the value returned from a call to clock() at the start of the program and the end to get maximum portability.

Note that the time can wrap around. On a 32bit system where CLOCKS_PER_SEC equals 1000000 this function will return the same value approximately every 72 minutes.

The times() function call returns more information.

times(2)