Path: utzoo!utgpu!news-server.csri.toronto.edu!qucdn!spraggej
Newsgroups: comp.lang.pascal
Subject: Re: more fun things to do with files
Organization: Queen's University at Kingston
Date: Thursday, 16 Aug 1990 19:24:38 EDT
From: John G. Spragge <SPRAGGEJ@QUCDN.QueensU.CA>
Message-ID: <90228.192439SPRAGGEJ@QUCDN.BITNET>
References:  <6789.26caaab3@jetson.uh.edu>

Not that much of a problem, since you can save each data structure as
a string of bytes. For example, consider the following:

  TYPE
     astruct = RECORD        { one data structure                  }
                 i : LONGINT;   { and other good things...         }
               END;

     bstruct = RECORD        { another data structure              }
                 s : STRING [100]; { and anything else you want... }
               END;

  VAR
     fds     : astruct;      { first data structure                }
     sds     : bstruct;      { second data structure               }
     saver   : FILE;         { untyped file to save f and s        }

  BEGIN
     fds.i := 100;
     sds.s := 'NO TYPE, BUT STILL SOME CLASS');

     REWRITE (saver, 1);     { saver is a file of BYTES            }
     BLOCKWRITE (saver, fds, SIZEOF (fds)); { write fds byte by byte }
     BLOCKWRITE (saver, sds, SIZEOF (sds)); { write sds byte by byte }
     CLOSE (saver);                         { finished writing... }

     RESET (saver, 1);        { open the file to read the data back }
     BLOCKREAD (saver, fds, SIZEOF (fds));  { read the first structure }
     BLOCKREAD (saver, sds, SIZEOF (sds));  { read the second structure }

     WRITELN (fds.i, ' ... ', sds.s);
  END.

Moral of the story: if you tell TURBO the (untyped) file record is
1 byte, you can get it to read your data byte by byte into your
data structures.

Disclaimer: I represent no one but myself, and none of this is
            guaranteed to work on your compiler.

               John Spragge