Associates a symbolic name with a constant value.

  The PARAMETER attribute can be specified in a type declaration
  statement or an PARAMETER statement, and takes one of the following
  forms:

  Type Declaration Statement:

   type, [att-ls,] PARAMETER [,att-ls] :: p=c [,p=c]...

  Statement:

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

     type      Is a data type specifier.

     att-ls    Is an optional list of attribute specifiers.

     p  Is the symbolic name of the constant.

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

  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.

  The PARAMETER attribute is compatible with the PRIVATE and PUBLIC
  attributes.

  For information on an alternate syntax for PARAMETER, see Help
  topic:  COMPATIBILITY_FEATURES PARAMETER.