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

  Associates a symbolic name with a constant value.  Statement
  format:

  1.   PARAMETER (p=c [,p=c]...)

     p  Is a symbolic name.

     c  Is a constant, a compile-time expression, or the
        symbolic name of a constant.

  The following additional rules apply to symbolic names:

   -  If the symbolic name is used as the length specifier in a
      CHARACTER declaration, it must be enclosed in parentheses.

   -  If the symbolic name is used as a numeric item in a FORMAT edit
      description, it must be enclosed in angle brackets.

   -  The symbolic name of a constant cannot appear as part of
      another constant, although it can appear as either the real or
      imaginary part of a complex constant.

   -  A symbolic name can be defined only once within the same
      program unit.

   -  You can only use a symbolic name defined to be a constant
      within the program unit containing the defining PARAMETER
      statement.

  The data type of a symbolic name associated with a constant is
  determined as follows:

   -  By an explicit type declaration statement preceding the
      defining PARAMETER statement

   -  By the same rules for implicit declarations that determine the
      data type of any other symbolic name

      For example, the following PARAMETER statement is interpreted
      as MU=1 (MU has an integer data type by implication):

         PARAMETER (MU=1.23)

      If the PARAMETER statement is preceded by an appropriate type
      declaration or IMPLICIT statement, it could be interpreted as
      MU=1.23; for example:

         REAL*8 MU
         PARAMETER (MU=1.23)

  Once a symbolic name is associated with a constant, it can appear
  anywhere in a program that any other constant can appear --- except
  in FORMAT statements (where constants can only be used in variable
  format expressions) and as the character count for Hollerith
  constants.  For compilation purposes, writing the name is the same
  as writing the value.

  A compile-time expression can contain the following intrinsic
  subprograms as long as the operands are constants:  ABS, CHAR,
  CMPLX, CONJG, DIM, DPROD, IAND, ICHAR, IEOR, IMAG, IOR, ISHFT, LGE,
  LGT, LLE, LLT, MIN, MAX, MOD, NINT, and NOT.

  2.     PARAMETER p=c [,p=c]...

     p  Is a symbolic name.

     c  Is a constant, the symbolic name of a constant, or a
        compile-time constant expression.

  This statement is similar to the one described above; they both
  assign a symbolic name to a constant.  However, this PARAMETER
  statement differs from the other one in the following two ways:
  its list is not bounded with parentheses; and the form of the
  constant, rather than implicit or explicit typing of the symbolic
  name, determines the data type of the variable.