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.