VMS Help CC, Language topics, Type Qualifiers, const  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The const data-type qualifier restricts access to stored data.  If
  you declare an object to be of type const, you cannot modify that
  object.  You can use the const data-type qualifier with the
  volatile data-type qualifier or with any of the storage-class
  specifiers or modifiers.  The following example declares the
  variable x to be a constant integer:

       int const x;