VMS Help FORTRAN, Intrinsic Procedures, SIZEOF  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  SIZEOF (arg)

  A function that returns the number of bytes of storage used by the
  argument.
  +------+---------+----------+---------------------------+-------------+
  | Args | Generic | Specific |       Argument            | Result Type |
  +------+---------+----------+---------------------------+-------------+
  |   1  |   --    | SIZEOF   | Anything with a valid     | INTEGER*4   |
  |      |         |          | data type, except assumed-|             |
  |      |         |          | size arrays or passed-    |             |
  |      |         |          | length characters.        |             |
  +------+---------+----------+---------------------------+-------------+