/sys$common/syshlp/helplib.hlb PASCAL, Attributes, READONLY  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The READONLY attribute specifies that an object can be read by a
  program, but cannot have values assigned to it.

  See the  "Compaq  Pascal  Language  Reference  Manual"  for  the
  complete description of using the READONLY attribute.