Overrides certain compiler options that can affect external routine
  and COMMON block declarations.

  It specifies that the compiler should ignore compiler options that
  change the default conventions for external symbol naming and
  argument passing for routines and COMMON blocks (/iface, /names,
  and /assume:underscore).

  This option can be combined with other cDEC$ ATTRIBUTES options,
  such as STDCALL, C, REFERENCE, ALIAS, etc.  to specify attributes
  different from the compiler defaults.

  This option is useful when declaring INTERFACE blocks for external
  routines, since it prevents compiler options from changing calling
  or naming conventions.