getut(3C)           (C Programming Language Utilities)            getut(3C)


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

   SYNOPSIS
         #include <utmp.h>

         struct utmp *getutent (void);

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

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

         struct utmp *pututline (const struct utmp *utmp);

         void setutent (void);

         void endutent (void);

         int utmpname (const char *file);

   DESCRIPTION
         getutent, getutid, getutline, and pututline each return a pointer to
         a structure with the following members:

                char       utuser[8];     /* User login name */
                char       utid[4];       /* /sbin/inittab id (usually line #) */
                char       utline[12];    /* device name (console, lnxx) */
                short      utpid;         /* process id   */
                short      uttype;        /* type of entry */
                struct     exitstatus {
                } utexit;                 /* The exit status of a process
                                            /* marked as DEADPROCESS. */
                timet     uttime;        /* time entry was made */

               The structure exit status includes the following members:

                         short   etermination;      /* Process termination status */
                         short   eexit;             /* Process exit status */

         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 RUNLVL, BOOTTIME, OLDTIME or NEWTIME.  If the
         type specified in id is INITPROCESS, LOGINPROCESS, USERPROCESS or
         DEADPROCESS, then getutid will return a pointer to the first entry
         whose type is one of these four and whose utid field matches id-
         >ut_id .  If the end of file is reached without a match, it fails.


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   getut(3C)           (C Programming Language Utilities)            getut(3C)


         getutline searches forward from the current point in the utmp file
         until it finds an entry of the type LOGINPROCESS or USERPROCESS
         that 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.  It returns a
         pointer to the utmp structure.

         setutent resets the input stream to the beginning of the file.  This
         reset 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 /var/adm/utmp to any other file.  It is most often expected that
         this other file will be /var/adm/wtmp.  If the file does not 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.  If the
         file name given is longer than 79 characters, utmpname returns 0.
         Otherwise, it will return 1.

   FILES
         /var/adm/utmp
         /var/adm/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.

   NOTES
         The most current entry is saved in a static structure.  Multiple
         accesses require that it be copied before further accesses are made.
         On each call to either getutid or getutline, the routine examines the
         static structure before performing more I/O.  If the contents of the
         static structure match what it is searching for, it looks no further.
         For this reason, to use getutline to search for multiple occurrences,
         it would be necessary to zero out the static area after each success,
         or getutline would just return the same structure over and over
         again.  There is one exception to the rule about emptying the


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   getut(3C)           (C Programming Language Utilities)            getut(3C)


         structure before further reads are done.  The implicit read done by
         pututline (if it finds that it is not 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.












































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