NAME
times —
process times
SYNOPSIS
#include
<sys/times.h>
clock_t
times(struct
tms *tp);
DESCRIPTION
The
times()
function fills in the structure pointed to by tp with
time-accounting information.
The tms structure is defined as follows:
struct tms {
clock_t tms_utime;
clock_t tms_stime;
clock_t tms_cutime;
clock_t tms_cstime;
};
The elements of this structure are defined as follows:
- tms_utime
- The CPU time charged for the execution of user instructions.
- tms_stime
- The CPU time charged for execution by the system on behalf of the process.
- tms_cutime
- The sum of tms_utime and tms_cutime for all of the child processes.
- tms_cstime
- The sum of tms_stime and tms_cstime for all of the child processes.
All times are in CLK_TCKs of a second.
The times of a terminated child process are included in the tms_cutime and tms_cstime elements of the parent when one of the wait(2) functions returns the process ID of the terminated child to the parent.
RETURN VALUES
Upon successful completion, times()
returns the value of real time, in CLK_TCKs of a
second, elapsed since an arbitrary point in the past. This point does not
change between invocations of times() so two such
return values constitute a real time interval.
On failure, times() returns
(clock_t)-1 and the global variable
errno is set to indicate the error.
ERRORS
The times() function may fail and set
errno for any of the errors specified for
clock_gettime(2) and
getrusage(2).
SEE ALSO
STANDARDS
The times() function conforms to
IEEE Std 1003.1-1988 (“POSIX.1”).
HISTORY
A times() function first appeared in
Version 3 AT&T UNIX. The tms structure
first appeared in 4.0BSD and was changed to use
clock_t instead of time_t for
its members in 4.3BSD-Net/2.