Saving many records to file

[BytePtr]

Im not newbie in programming, just trying to learn more every day with my experiments.
I need to create one specific file, like described in documenttation of file format. But my problem is how to write many records in file? Look my code.

type
   tmy_file_header=record
      file_type:array[0..3] of Char;
      vers_code:Word;
end;

mfh: tmy_file_header;
f: file of tmy_file_header;

procedure TForm1.Button1Click(Sender: TObject);
begin
   assignfile(f,'c:\data.dat');
   {$I-}
      reset(f);
      seek(f, filesize(f));
   {$I+}
   if ioresult=0 then
   begin
      // write
      mfh.file_type:='MHDR';
      mfh.vers_code:=100;
      write(f,mfh);
   end
   else
      begin
         {$I-}
            rewrite(f);
         {$I+}
         if ioresult=0 then
         begin
            // write
            mfh.file_type:='MHDR';
            mfh.vers_code:=100;
            write(f,mfh);
         end
         else
            showmessage('Unable to create file!');
      end;
end;

tmy_file_header is my first record, but i must to create more records and write them all to one file, without removing/corrupting previous data from/in file.

If i write another:

f: file of other_record;

then Delphi displays error: "Incompatible types: first record and other record"

Creating every time new F type is not good way.
How to solve this problem? Any ideas?

btw: i just started learning using delphi "record and type".

[cairnswm]

Have a look at BlockRead and Blockwrite. They allow you to write records of anysize to a file.

[BytePtr]

Thanks for reply.
I decided to use streams. I think they solved my problem.

type
   tmy_header=record
      f_type:array[0..3] of char;
      codez:word;
   end;

   tmy_header2=record
      typez:array[0..3] of char;
      sizez:longword;
end;

 mh: tmy_header
  cht: tmy_header2;

  fname: string; // filename
  fstream: tfilestream;

procedure TForm1.Button1Click(Sender: TObject);
begin
   fname:='c:\data.dat';
   fstream:=tfilestream.Create(fname, fmCreate or fmOpenWrite or fmShareExclusive);
   try
      mh.f_type:='MHDR';
      mh.codez:=100;

      cht.typez:='RDHM';
      cht.sizez:=255;

      fstream.Write(mh,sizeof(mh));
      fstream.Write(cht,sizeof(cht));

   finally
      fstream.Free;
end;

Now the data is correctly in my file, i will try to write more and look how it will work.I have original editor for this file, so i can test with this also, how it loads my file after i create it with my program. Until now it loads my created file OK.
If i have any problems with this, then i will let u know.

Thanks so far