#include <sys/time.h>
     #include <sys/resource.h>
     #define   RUSAGE_SELF     0
     #define   RUSAGE_CHILDREN     -1

     int
     getrusage(int who, struct rusage *rusage)

DESCRIPTION

     Getrusage() returns information describing the resources utilized by the
     current process, or all its terminated child processes.  The who parame-
     ter is either RUSAGE_SELF or RUSAGE_CHILDREN. The buffer to which rusage
     points will be filled in with the following structure:

     struct rusage {
             struct timeval ru_utime; /* user time used */
             struct timeval ru_stime; /* system time used */
             long ru_maxrss;          /* integral max resident set size */
             long ru_ixrss;           /* integral shared text memory size */
             long ru_idrss;           /* integral unshared data size */
             long ru_isrss;           /* integral unshared stack size */
             long ru_minflt;          /* page reclaims */
             long ru_majflt;          /* page faults */
             long ru_nswap;           /* swaps */
             long ru_inblock;         /* block input operations */
             long ru_oublock;         /* block output operations */
             long ru_msgsnd;          /* messages sent */
             long ru_msgrcv;          /* messages received */
             long ru_nsignals;        /* signals received */
             long ru_nvcsw;           /* voluntary context switches */
             long ru_nivcsw;          /* involuntary context switches */
     };

     The fields are interpreted as follows:

     ru_utime     the total amount of time spent executing in user mode.

     ru_stime     the total amount of time spent in the system executing on
                  behalf of the process(es).

     ru_maxrss    the maximum resident set size utilized (in kilobytes).

     ru_ixrss     an integral value indicating the amount of memory used by
                  the text segment that was also shared among other processes.
                  This value is expressed in units of kilobytes * ticks-of-ex-
                  ecution.

     ru_idrss     an integral value of the amount of unshared memory residing
                  in the data segment of a process (expressed in units of
                  kilobytes * ticks-of-execution).

     ru_isrss     an integral value of the amount of unshared memory residing
     ru_inblock   the number of times the file system had to perform input.

     ru_oublock   the number of times the file system had to perform output.

     ru_msgsnd    the number of IPC messages sent.

     ru_msgrcv    the number of IPC messages received.

     ru_nsignals  the number of signals delivered.

     ru_nvcsw     the number of times a context switch resulted due to a pro-
                  cess voluntarily giving up the processor before its time
                  slice was completed (usually to await availability of a re-
                  source).

     ru_nivcsw    the number of times a context switch resulted due to a high-
                  er priority process becoming runnable or because the current
                  process exceeded its time slice.

NOTES

     The numbers ru_inblock and ru_oublock account only for real I/O; data
     supplied by the caching mechanism is charged only to the first process to
     read or write the data.

ERRORS

     Getrusage() returns -1 on error.  The possible errors are:

     [EINVAL]      The who parameter is not a valid value.

     [EFAULT]      The address specified by the rusage parameter is not in a
                   valid part of the process address space.

SEE ALSO

     gettimeofday(2),  wait(2)

BUGS

     There is no way to obtain information about a child process that has not
     yet terminated.

HISTORY

     The getrusage() function call appeared in 4.2BSD.

4th Berkeley Distribution        June 4, 1993                                2