routine returns the login class name associated with the calling process,
as previously set by
The caller must provide the buffer
bytes to hold the result.
The buffer should be at least
bytes in length.
system call sets the login class of the calling process to
This system call is restricted to the super-user, and is normally used
only when a new session is being created on behalf of the named user
(for example, at login time, or when a remote shell is invoked).
Processes inherit login class from their parents.