


      GETUT(3C)                   (UNIX 5.0)                  GETUT(3C)



      NAME
           getutent, getutid, getutline, pututline, setutent, endutent,
           utmpname - access utmp file entry

      SYNTAX
           #include <utmp.h>

           struct utmp *getutent ( )

           struct utmp *getutid (id)
           struct utmp *id;

           struct utmp *getutline (line)
           struct utmp *line;

           void pututline (utmp)
           struct utmp *utmp;

           void setutent ( )

           void endutent ( )

           void utmpname (file)
           char *file;

      DESCRIPTION
           Getutent, getutid and getutline each return a pointer to a
           structure of the following type:

           struct utmp {
             char  ut_user[8];      /* User login name */
             char  ut_id[4];        /* /etc/inittab id (usually line #) */
             char  ut_line[12];     /* device name (console, lnxx) */
             short   int ut_pid;    /* process id */
             short   int ut_type;   /* type of entry */
             struct  exit_status {
                short    e_termination; /* Process termination status */
                short    e_exit;    /* Process exit status */
             } ut_exit;             /* The exit status of a process
                                     * marked as DEAD_PROCESS. */
             time_t    ut_time;     /* time entry was made */
           };

           Getutent reads in the next entry from a utmp-like file.  If
           the file is not already open, it opens it.  If it reaches
           the end of the file, it fails.

           Getutid searches forward from the current point in the utmp
           file until it finds an entry with a ut_type matching
           id->ut_type if the type specified is RUN_LVL, BOOT_TIME,
           OLD_TIME or NEW_TIME.  If the type specified in id is
           INIT_PROCESS, LOGIN_PROCESS, USER_PROCESS or DEAD_PROCESS,



      Page 1                                         (73 A2 02MTA REV1)






      GETUT(3C)                   (UNIX 5.0)                  GETUT(3C)



           then getutid will return a pointer to the first entry whose
           type is one of these four and whose ut_id field matches
           id->ut_id.  If the end of file is reached without a match,
           it fails.

           Getutline searches forward from the current point in the
           utmp file until it finds an entry of the type LOGIN_PROCESS
           or USER_PROCESS which also has a ut_line string matching the
           line->ut_line string.  If the end of file is reached without
           a match, it fails.

           Pututline writes out the supplied utmp structure into the
           utmp file.  It uses getutid to search forward for the proper
           place if it finds that it is not already at the proper
           place.  It is expected that normally the user of pututline
           will have searched for the proper entry using one of the
           getut routines.  If so, pututline will not search.  If
           pututline does not find a matching slot for the new entry,
           it will add a new entry to the end of the file.

           Setutent resets the input stream to the beginning of the
           file.  This should be done before each search for a new
           entry if it is desired that the entire file be examined.

           Endutent closes the currently open file.

           Utmpname allows the user to change the name of the file
           examined, from /etc/utmp to any other file.  It is most
           often expected that this other file will be /etc/wtmp.  If
           the file doesn't exist, this will not be apparent until the
           first attempt to reference the file is made.  Utmpname does
           not open the file.  It just closes the old file if it is
           currently open and saves the new file name.

      FILES
           /etc/utmp
           /etc/wtmp

      SEE ALSO
           ttyslot(3C), utmp(4).

      DIAGNOSTICS
           A NULL pointer is returned upon failure to read, whether for
           permissions or having reached the end of file, or upon
           failure to write.

      COMMENTS
           The most current entry is saved in a static structure.
           Multiple accesses require that it be copied before further
           accesses are made.  Each call to either getutid or getutline
           sees the routine examine the static structure before
           performing more I/O.  If the contents of the static



      Page 2                                         (73 A2 02MTA REV1)






      GETUT(3C)                   (UNIX 5.0)                  GETUT(3C)



           structure match what it is searching for, it looks no
           further.  For this reason to use getutline to search for
           multiple occurences, it would be necessary to zero out the
           static after each success, or getutline would just return
           the same pointer over and over again.  There is one
           exception to the rule about removing the structure before
           further reads are done.  The implicit read done by pututline
           if it finds that it isn't already at the correct place in
           the file will not hurt the contents of the static structure
           returned by the getutent, getutid or getutline routines, if
           the user has just modified those contents and passed the
           pointer back to pututline.

           These routines use buffered standard I/O for input, but
           pututline uses an unbuffered non-standard write to avoid
           race conditions between processes trying to modify the utmp
           and wtmp files.






































      Page 3                                         (73 A2 02MTA REV1)



