December 14, 1995 LOGIN 3

### NAME

login, logout, logwtmp - login utility functions

### LIBRARY

System Utilities Library (libutil, -lutil)

### SYNOPSIS

```void` login(```struct utmp *ut`)
```int` logout(```const char *line`)
```void` logwtmp(```const char *line``, const char *name``, const char *host`)

### DESCRIPTION

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.

### RETURN VALUES

logout(``) returns non-zero if it was able to find and delete an entry for ```line`, and zero if there is no entry for ```line` in ```/var/run/utmp`.

### FILES

```/dev/*`
```/etc/ttys`
```/var/run/utmp`
```/var/log/wtmp`

### SEE ALSO

utmp(5)