UTMP(5)                 GENIX Programmer's Manual                 UTMP(5)



      NAME
           utmp, wtmp - login records

      SYNOPSIS
           #include <utmp.h>

      DESCRIPTION
           The utmp file allows  one  to  discover  information  about  who  is
           currently  using  UNIX.   The file is a sequence of entries with the
           following structure declared in the include file:

                /*
                 * @(#)utmp.h  1.2  7/13/83
                 * @(#)Copyright (C) 1983 by National Semiconductor Corp.
                 */

                /*
                 * Structure of utmp and wtmp files.
                 *
                 * Assuming the number 8 is unwise.
                 */
                struct utmp {
                     char ut_line[8];         /* tty name */
                     char ut_name[8];         /* user id */
                     long ut_time;       /* time on */
                };

           This structure gives the name of the special  file  associated  with
           the  user's  terminal,  the  user's  login name, and the time of the
           login in the form of time(2).

           The wtmp file records all logins and logouts.  Its format is exactly
           like  utmp  except  that  a null user name indicates a logout on the
           associated terminal.  Furthermore, the terminal name  `~'  indicates
           that  the  system  was  rebooted at the indicated time; the adjacent
           pair of entries  with  terminal  names  `|'  and  `}'  indicate  the
           system-maintained time just before and just after a date command has
           changed the system's idea of the time.

           Wtmp is maintained by login(1) and init(8).  Neither of  these  pro-
           grams creates the file, so if it is removed record-keeping is turned
           off.  It is summarized by ac(8).

      FILES
           /etc/utmp
           /usr/adm/wtmp

      SEE ALSO
           login(1), init(8), who(1), ac(8)






      Printed 11/16/83                                                        1