VMS Help DECTPU, TPU$EXECUTE_COMMAND, Argument  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 string

    OpenVMS usage:char_string
    type:         character string
    access:       read only
    mechanism:    by value
    DECTPU statement. The string argument is the address of a
    descriptor of a character string denoting one or more DECTPU
    statements.