HP FORTRAN provides several general-purpose compiler directives
  to perform tasks during compilation.

  General directives begin with the cDEC$ prefix.  These directives
  are enabled in all Fortran compilation units, regardless of the
  options used on the command line.

  The general directives are:

  ALIAS                       MESSAGE
  ATTRIBUTES                  OBJCOMMENT
  DECLARE and NODECLARE       OPTIONS
  DEFINE and UNDEFINE         PACK
  FIXEDFORMLINESIZE           PSECT
  FREEFORM and NOFREEFORM     REAL
  IDENT                       STRICT and NOSTRICT
  IF and IF DEFINED           SUBTITLE and TITLE
  INTEGER                     UNROLL
  IVDEP

  The "c" in the directive prefix (cDEC$) is one of the following:  C
  (or c), !, or *.

  The following are source form rules for directive prefixes:

   o  Prefixes beginning with C (or c) and * are only allowed in
      fixed and tab source forms.

      In these source forms, the prefix must appear in columns 1
      through 5; column 6 must be a blank or tab.  From column 7 on,
      blanks are insignificant, so the directive can be positioned
      anywhere on the line after column 6.

   o  Prefixes beginning with !  are allowed in all source forms.

      The prefix can appear in any valid column, but it cannot be
      preceded by any nonblank characters on the same line.  It can
      only be preceded by whitespace.

  A general directive ends in column 72 (or column 132, if a compiler
  option is specified).

  General directives cannot be continued.

  A comment can follow a directive on the same line.

  Additional Fortran statements (or directives) cannot appear on the
  same line as the general directive.

  General directives cannot appear within a continued Fortran
  statement.

  If a blank common is used in a general compiler directive, it must
  be specified as two slashes (/ /).