SDL, LANGUAGES, Data Structure/Interface Definition Language

  Version Info:

  Alpha PL/I SDL for OpenVMS VAX, EV1-39
  Alpha PL/I SDL for OpenVMS Alpha, EV1-69
  Alpha C++ SDL for OpenVMS VAX, Alpha and I64, V2.1-5

  Alpha PL/I SDL VAX EV1-39 has not been changed from the version
  found Freeware V6.0, while the Alpha PL/I SDL Alpha EV1-69 images,
  and the Alpha C++ SDL VAX, Alpha and I64 V2.1-5 kit, are new.
  The PL/I source code to Alpha PL/I SDL EV1-69 is provided.  No
  code for the C++ port is presently provided.

  The SDL Tool:

  This tool is a data definition language and is used to convert a 
  language-independent definition file (an SDL input file) into a 
  language-dependent definition file.  Alone or in conjunction with 
  mechanisms such as the OpenVMS MESSAGE/SDL command (a latent and
  undocumented qualifier which converts the .MSG file into an SDL
  file) and the Freeware GNM tool, the SDL tool can be used to 
  maintain common sources for a wide variety of language files.

  Directory Organization:

  This version of SDL includes PL/I sources and images for use on 
  OpenVMS VAX systems (in [.SDL_PLI_VAX_IMAGES]) and on OpenVMS 
  Alpha (in [.SDL_PLI_ALPHA_IMAGES]) systems.  These images were
  built with/for/on OpenVMS V7.3 and V7.3-2, respectively.

  Also present here is a PCSI installation kit containing the C++
  port of Alpha SDL for OpenVMS VAX, OpenVMS Alpha, and OpenVMS I64
  systems.  To use this kit, use PRODUCT INSTALL to install the PCSI
  kit, and the kit will install and register the kit, including 
  adding the SDL verb definition to the command tables.

  To use the Alpha SDL PL/I tool, the provided SDL.COM procedure 
  will create logical names for the correct set of images for the
  local system architecture, and will also load the SDL.CLD command
  definition into the current process.   (No DCL procedure is 
  needed for use of the C++ port; with the version of SDL in the
  PCSI kit.)

  The two version of Alpha SDL here -- the PL/I version and the C++
  version -- are expected to be source compatible, though additional
  work, enhancements and operations on OpenVMS I64 are probably only 
  reasonably (likely?) expected within the Alpha SDL C++ variant.

  Usage:

  To invoke the Alpha SDL PL/I variant:

  $ @SDL  ! needed once, and then only for the PL/I version

  then

  $ SDL/ALPHA/LANGUAGE=CC filedef.SDL

  or

  $ SDL/VAX/LANGUAGE=CC filedef.SDL

  Also available is SDL/NOPARSE, which converts the intermediate
  files (.SDI files) found in STARLETSD.TLB into language-specific
  definition files.

