The Invoke $FAOL System Service to Format Output routine calls
    the $FAOL system service, returning the string in the semantics
    you provide. If called with other than a fixed-length string
    for output, the length of the resultant string is limited to 256
    bytes and truncation occurs.

    Format

      LIB$SYS_FAOL  character-string [,resultant-length]

                    ,resultant-string ,directive-argument-address