NAME

times — process times

LIBRARY

Standard C Library (libc, -lc)

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

time(1), getrusage(2), gettimeofday(2), wait(2), sysconf(3)

STANDARDS

The times() function conforms to IEEE Std 1003.1-1990 (“POSIX.1”).