OberonCore

typedef struct SDL_RWops {
   /* Seek to 'offset' relative to whence, one of stdio's whence values:
      SEEK_SET, SEEK_CUR, SEEK_END
      Returns the final offset in the data source.
    */
   int (SDLCALL *seek)(struct SDL_RWops *context, int offset, int whence);

   /* Read up to 'num' objects each of size 'objsize' from the data
      source to the area pointed at by 'ptr'.
      Returns the number of objects read, or -1 if the read failed.
    */
   int (SDLCALL *read)(struct SDL_RWops *context, void *ptr, int size, int maxnum);

   /* Write exactly 'num' objects each of size 'objsize' from the area
      pointed at by 'ptr' to data source.
      Returns 'num', or -1 if the write failed.
    */
   int (SDLCALL *write)(struct SDL_RWops *context, const void *ptr, int size, int num);

   /* Close and free an allocated SDL_FSops structure */
   int (SDLCALL *close)(struct SDL_RWops *context);

   Uint32 type;
   union {
#ifdef __WIN32__
       struct {
      int    append;
      void*  h;
       } win32io;
#endif
#ifdef HAVE_STDIO_H
       struct {
      int autoclose;
      FILE *fp;
       } stdio;
#endif
       struct {
      Uint8 *base;
      Uint8 *here;
      Uint8 *stop;
       } mem;
       struct {
      void *data1;
       } unknown;
   } hidden;

} SDL_RWops;

IMPORT SYSTEM;

TYPE
SDL_RWops = RECORD [untagged]
  seek: PROCEDURE (context: POINTER TO SDL_RWops; ptr: INTEGER (*и передавать SYSTEM.ADR *); size, maxnum: INTEGER);
  write: PROCEDURE (context: POINTER TO SDL_RWops; ptr: INTEGER; size, num: INTEGER);
  type: INTEGER;
  (* WIN32 *)
  hidden: RECORD [union]
     win32io: RECORD append: INTEGER; h: INTEGER END;
     stdio: RECORD autoclose: INTEGER; fp: INTEGER END;
     mem: RECORD base, here, stop: INTEGER END;
     unknown: RECORD data1: INTEGER END
  END
END

TYPE
  ADDRESS = INTEGER;
  PtrUint8 = POINTER TO ARRAY [untagged] OF SHORTCHAR;

  SDL_RWops = RECORD [untagged]
    seek  : PROCEDURE ( VAR context: SDL_RWops; offset, whence: INTEGER): INTEGER;
    read  : PROCEDURE ( VAR context: SDL_RWops; ptr: ADDRESS; size, maxnum:INTEGER ): INTEGER;
    write : PROCEDURE ( VAR context: SDL_RWops; ptr: ADDRESS; size, num: INTEGER ): INTEGER;
    close : PROCEDURE ( VAR context: SDL_RWops): INTEGER;
    type  : INTEGER;
    hidden:  RECORD [union]
      win32io: RECORD append: INTEGER; h : ADDRESS END;
      stdio  : RECORD autoclose: INTEGER; fp : ADDRESS END;
      mem    : RECORD base, here, stop: PtrUint8 END;
      unknown: RECORD data1: ADDRESS END;
    END;
  END;

 ptr2func* = PROCEDURE ( x: REAL ): REAL;
PROCEDURE  Funcres* ["Funcres"] ( f: ptr2func; a: REAL ): REAL;

...
PROCEDURE f(x: REAL): REAL;
      VAR 
   BEGIN
      RETURN  x*x*x*x;
   END f;
...
z:= TestInterface.Funcres(f, 2.0);

ptr2func* = PROCEDURE [call] ( x: REAL ): REAL;
PROCEDURE  Funcres* ["Funcres"] ( f: ptr2func; a: REAL ): REAL;

PROCEDURE  Funcres* ["Funcres"] ( f: PROCEDURE [call] ( x: REAL ): REAL; a: REAL ): REAL;

PROCEDURE [call] f(x: REAL): REAL;
  VAR
BEGIN
  RETURN  x*x*x*x;
END f;

PROCEDURE  Funcres* ["Funcres"] ( f: PROCEDURE ( x: REAL ): REAL; a: REAL ): REAL;

PROCEDURE [call] f(x: REAL): REAL;
...

double __stdcall Funcres(ptr2func f, double a)...