-lang  {c, cxx, fortran}

   Allows you to select a programming language.

   If you are generating stubs and include files for application code
   written in C++, you must specify cxx as the language of choice when
   you compile the application's IDL file.  When appropriate, you can
   extend the class hierarchy and derive other classes from this one,
   to implement some or all interface operations. The C++ compiler
   gives a warning if any functions in the interface class have not
   been implemented. Avoid overwriting the manager class header file
   by using the -no_cxxmgr argument in conjunction with the -lang cxx
   argument.

   If you are generating stubs and include files for application code
   written in FORTRAN, you must specify FORTRAN as the language of
   choice when you compile the application's IDL file.

   If you do not specify -lang fortran or -lang cxx, the default value
   is the C programming language or -lang c.