VMS Help LGI Routines, LGI$ICB_USERPARSE, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The site can use this callback routine to parse input for
    interactive logins on character-cell and DECwindows terminals.

    Upon completion of this routine, the user name is accessible at
    the LGI$A_USERNAME entry in the standard arguments vector.