The
login(),
logout(), and
logwtmp() functions operate on the database of current users in
/var/run/utmp and on the logfile
/var/log/wtmp of logins and logouts.
The
login() function updates the
/var/run/utmp and
/var/log/wtmp files with user information contained in
ut.
The
logout() function removes the entry from
/var/run/utmp corresponding to the device
line.
The
logwtmp() function adds an entry to
/var/log/wtmp. Since
login() will add the appropriate entry for
/var/log/wtmp during a login,
logwtmp() is usually used for logouts.