Overrides or confirms the compiler options in effect for a program
  unit.  Statement format:

     OPTIONS option [option...]

     option  Is one of the following:

     /ASSUME=[NO]UNDERSCORE

     /CHECK=(ALL, [NO]BOUNDS, [NO]OVERFLOW, [NO]UNDERFLOW, NONE)
     /NOCHECK

     /CONVERT=(BIG_ENDIAN, CRAY, FDX, FGX, IBM, LITTLE_ENDIAN,
              NATIVE, VAXD, VAXG)

     /[NO]EXTEND_SOURCE
     /[NO]F77
     /FLOAT=(D_FLOAT, G_FLOAT, IEEE_FLOAT)
     /[NO]G_FLOATING
     /[NO]I4
     /[NO]RECURSIVE

  You must place the slash (/) before the option.

  The OPTIONS statement must be the first statement in a program
  unit, preceding the PROGRAM, SUBROUTINE, FUNCTION, MODULE, and
  BLOCK DATA statements.

  OPTIONS statement options have the same syntax and abbreviations as
  their similarly-named VMS compiler options.

  OPTIONS statement options override compiler options, but only until
  the end of the program unit for which they are defined.  Thus, an
  OPTIONS statement must appear before each program unit in which you
  wish to override the compiler options.