Opening a File Mapped

   procedure Mapped_File_Example;
   type
     record_t = record             {** defines an 80-byte record **}

                  a_record : packed array [1..80] of char;
                end;
     file_t = array [1..50000] of record_t;
                               {** define a 4,000,000 byte array **}
   var
     access,domain       : integer;
     dummy               : shortint;
     file_name           : packed array [1..20] of char;
     file_number         : integer;
     file_ptr            :^file_t; {** pointer to the file **}
     filesize            : integer;
     index, rec          : integer;
     create_domain_perm  : integer;
     read_write_access   : integer;
     domain_old          : integer;
     status              : record
                             case integer of
                               0:    (all:    integer);
                               1:    (info:   shortint;
                                      subsys:  shortint);
                           end;
   const
     file_name_option     =   2;
     domain_option        =   3;
     filesize option      =  35;
     short_mapped_option  =  18;
     access_type_option   =  11;

   begin
                   {** initialize item values for the HPFOPEN **}
        file_name           := '%EXAMPLE%';
        create_domain_PERM  := 4;
        domain_OLD          := 3;
        filesize            := 15265;
        read_write_access   := 4;

                    {** create a short-mapped file **}
        HPFOPEN (
                  file_number, status,
                  file_name_option, file_name
                  domain_option,create_domain_PERM,
                  filesize option, filesize,
                  short_mapped_option, file_ptr,
                  access_type_option, read_write_access,
                );
                    {** put some data into the file **}
        for rec := 1 to 100 do
             for index := 1 to 80 do
                  file_ptr^[rec].a_record[index] :=
                            Chr (((rec - 1) Mod 26) + 65);

                       {** set the logical record pointer **}
        FPOINT (file_number, 33);
        FCONTROL (file_number, 6, dummy);        {** set the EOF **}
        FCLOSE (file_number, 0, 0);            {**close the file **}

                          {** re-open the same short-mapped file **}
        HPFOPEN (
                  file_number, status,
                  file_name_option, file_name,
                  domain_option, domain_OLD,
                  short_mapped_option, file_ptr,
                );

                          {** retrieve some data you put in file **}
        for rec := 1 to 100 do
        begin
             write ('Record-', rec:4, ' ');
             for index := 1 to 20 do
                  write (file_ptr^[rec].a_record[index]; 
             writeln;
        end;
                                    {** close and purge the file **}
        FCLOSE (file_number, 4, 0);
   end;