NAME
times
—
process times
LIBRARY
library “libc”
SYNOPSIS
#include
<sys/times.h>
clock_t
times
(struct
tms *tp);
DESCRIPTION
The
times
()
function returns the value of time in clock ticks since 0 hours, 0 minutes,
0 seconds, January 1, 1970, Coordinated Universal Time (UTC).
The number of clock ticks per second may be determined by calling
sysconf(3) with the _SC_CLK_TCK
request. It
is generally (but not always) between 60 and 1024.
Note that at the common rate of 100 ticks per second on many NetBSD ports, and with a 32-bit unsigned clock_t, this value first wrapped in 1971.
The
times
()
call also fills in the structure pointed to by tp with
time-accounting information.
The tms structure is defined as follows:
typedef struct { 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 the tms_utime s and tms_cutime s of the child processes.
- tms_cstime
- The sum of the tms_stimes and tms_cstimes of the child processes.
All times are measured in clock ticks, as defined above. Note that at 100 ticks per second, and with a 32-bit unsigned clock_t, the values wrap after 497 days.
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. If an error occurs,
times
()
returns the value ((clock_t)-1), and sets errno to
indicate the error.
ERRORS
The times
() function may fail and set the
global variable errno for any of the errors specified
for the library routines
getrusage(2) and
gettimeofday(2).
SEE ALSO
STANDARDS
The times
() function conforms to
IEEE Std 1003.1-1990 (“POSIX.1”).