NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

       #include <utmp.h>

       struct utmp *getutent(void);
       struct utmp *getutid(struct utmp *ut);
       struct utmp *getutline(struct utmp *ut);

       void pututline(struct utmp *ut);

       void setutent(void);
       void endutent(void);

       void utmpname(const char *file);

DESCRIPTION    [Toc]    [Back]

       utmpname() sets the name of the utmp-format file  for  the  other  utmp
       functions  to  access.	If  utmpname() is not used to set the filename
       before the other functions are used, they assume _PATH_UTMP, as defined
       in <paths.h>.

       setutent()  rewinds the file pointer to the beginning of the utmp file.
       It is generally a Good Idea to call it before any of  the  other  functions.


       endutent()  closes  the	utmp  file.  It should be called when the user
       code is done accessing the file with the other functions.

       getutent() reads a line from the current  file  position  in  the  utmp
       file.  It returns a pointer to a structure containing the fields of the
       line.

       getutid() searches forward from the current file position in  the  utmp
       file based upon ut.  If ut->ut_type is RUN_LVL, BOOT_TIME, NEW_TIME, or
       OLD_TIME, getutid() will find  the  first  entry  whose	ut_type  field
       matches	 ut->ut_type.	 If   ut->ut_type   is	one  of  INIT_PROCESS,
       LOGIN_PROCESS, USER_PROCESS, or DEAD_PROCESS, getutid() will  find  the
       first entry whose ut_id field matches ut->ut_id.

       getutline() searches forward from the current file position in the utmp
       file.  It scans entries whose ut_type is USER_PROCESS or  LOGIN_PROCESS
       and returns the first one whose ut_line field matches ut->ut_line.

       pututline()  writes  the utmp structure ut into the utmp file.  It uses
       getutid() to search for the proper place in the file to insert the  new
       entry.	If it cannot find an appropriate slot for ut, pututline() will
       append the new entry to the end of the file.

RETURN VALUE    [Toc]    [Back]

       getutent(), getutid(), and getutline() return a	pointer  to  a	static
       struct utmp.

ERRORS    [Toc]    [Back]

       On error, (struct utmp*)0 will be returned.

EXAMPLE    [Toc]    [Back]

       The  following  example	adds and removes a utmp record, assuming it is
       run from within a pseudo terminal.  For usage in  a  real  application,
       you should check the return values of getpwuid() and ttyname().

       #include <string.h>
       #include <stdlib.h>
       #include <pwd.h>
       #include <unistd.h>
       #include <utmp.h>

       int main(int argc, char *argv[])
       {
	 struct utmp entry;

	 system("echo before adding entry:;who");

	 entry.ut_type=USER_PROCESS;
	 entry.ut_pid=getpid();
	 strcpy(entry.ut_line,ttyname(0)+strlen("/dev/"));
	 /* only correct for ptys named /dev/tty[pqr][0-9a-z] */
	 strcpy(entry.ut_id,ttyname(0)+strlen("/dev/tty"));
	 time(&entry.ut_time);
	 strcpy(entry.ut_user,getpwuid(getuid())->pw_name);
	 memset(entry.ut_host,0,UT_HOSTSIZE);
	 entry.ut_addr=0;
	 setutent();
	 pututline(&entry);

	 system("echo after adding entry:;who");

	 entry.ut_type=DEAD_PROCESS;
	 memset(entry.ut_line,0,UT_LINESIZE);
	 entry.ut_time=0;
	 memset(entry.ut_user,0,UT_NAMESIZE);
	 setutent();
	 pututline(&entry);

	 system("echo after removing entry:;who");

	 endutent();
	 return 0;
       }

FILES    [Toc]    [Back]

       /var/run/utmp  database of currently logged-in users
       /var/log/wtmp  database of past user logins

CONFORMING TO    [Toc]    [Back]

       XPG 2, SVID 2, Linux FSSTND 1.2

SEE ALSO    [Toc]    [Back]

       utmp(5)



				  1996-07-25			   GETUTENT(3)