clock
NAME
clock - Determine processor time
SYNOPSIS
#include <time.h> clock_t clock(void);
DESCRIPTION
The
R clock ()
function returns an approximation of processor time used by the program.
RETURN VALUE
The value returned is the CPU time used so far as a
R clock_t ;
to get the number of seconds used, divide by
R CLOCKS_PER_SEC .
If the processor time used is not available or its value cannot
be represented, the function returns the value
R (clock_t)-1 .
CONFORMING TO
C89, C99, POSIX.1-2001.
POSIX requires that CLOCKS_PER_SEC equals 1000000 independent
of the actual resolution.
NOTES
The C standard allows for arbitrary values at the start of the program;
subtract the value returned from a call to
R clock ()
at the start of the program 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.
On several other implementations,
the value returned by
R clock ()
also includes the times of any children whose status has been
collected via
wait(2)
(or another wait-type call).
Linux does not include the times of waited-for children in the
value returned by
R clock ().
The
times(2)
function, which explicitly returns (separate) information about the
caller and its children, may be preferable.
ČLÁNKY DO MAILU