getut(3C)                        DG/UX 5.4.2                       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;                 /* exit status of a process */
                                        /* marked as DEADPROCESS */
             timet     uttime;        /* time entry was made */

       The structure exit status includes the following members:

                 short   etermination;      /* termination status */
                 short   eexit;             /* 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 uttype 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,
       character by character, 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



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getut(3C)                        DG/UX 5.4.2                       getut(3C)


       until it finds an entry of the type LOGINPROCESS or USERPROCESS
       that also has a utline 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 /etc/utmp to any other file.  It is most often expected that
       this other file will be /etc/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
       /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.

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
       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



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getut(3C)                        DG/UX 5.4.2                       getut(3C)


       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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