+.PP
+The fields are interpreted as follows:
+.TP 15
+ru_utime
+the total amount of time spent executing in user mode.
+.TP 15
+ru_stime
+the total amount of time spent in the system executing on behalf
+of the process(es).
+.TP 15
+ru_maxrss
+the maximum resident set size utilized (in kilobytes).
+.TP 15
+ru_ixrss
+an \*(lqintegral\*(rq value indicating the amount of memory used
+which was also shared among other processes. This value is expressed
+in units of kilobytes * seconds-of-execution and is calculated by
+summing the number of shared memory pages in use each time the internal
+system clock ticks and then averaging over 1 second intervals.
+.TP 15
+ru_idrss
+an integral value of the amount of unshared memory residing in the
+data segment of a process (expressed in units of
+kilobytes * seconds-of-execution).
+.TP 15
+ru_isrss
+an integral value of the amount of unshared memory residing in the
+stack segment of a process (expressed in units of
+kilobytes * seconds-of-execution).
+.TP 15
+ru_minflt
+the number of page faults serviced without any i/o activity; here
+i/o activity is avoided by \*(lqreclaiming\*(rq a page frame from
+the list of pages awaiting reallocation.
+.TP 15
+ru_majflt
+the number of page faults serviced which required i/o activity.
+.TP 15
+ru_nswap
+the number of times a process was \*(lqswapped\*(rq out of main
+memory.
+.TP 15
+ru_inblock
+the number of times the file system had to perform input.
+.TP 15
+ru_outblock
+the number of times the file system had to perform output.
+.TP 15
+ru_msgsnd
+the number of ipc messages sent.
+.TP 15
+ru_msgrcv
+the number of ipc messages received.
+.TP 15
+ru_nsignals
+the number of signals delivered.
+.TP 15
+ru_nvcsw
+the number of times a context switch resulted due to a process
+voluntarily giving up the processor before its time slice was
+completed (usually to await availability of a resource).
+.TP 15
+ru_nivcsw
+the number of times a context switch resulted due to a higher
+priority process becoming runnable or because the current process
+exceeded its time slice.
+.SH NOTES
+The numbers
+.I ru_inblock
+and
+.I ru_outblock
+account only for real
+i/o; data supplied by the cacheing mechanism is charged only
+to the first process to read or write the data.
+.SH SEE ALSO
+gettimeofday(2), wait(2)
+.SH BUGS
+There is no way to obtain information about a child process
+which has not yet terminated.