Article #15840: FILE HANDLES EXTENDING

 Technical Notes Database

TN840D.txt   FILE HANDLES EXTENDING
Category   :Pascal
Platform    :All
Product    :Turbo Pascal  4.0+

Description:
Q. How do I open more than 15 files at one time?
A. In DOS version 3.3 and above there is a function call to allocate memory
   for additional file handles.  This will allow you to open more than 15
   files at one time as long as your Files line in your CONFIG.SYS is 5
   greater than the number of files you would like to open.
   Here is an example program:
      {$M $8000,0,$1000}  { Important do not forget }
      Program Many_Files;
        Uses Dos;
        Var
          Files:array[1..30] of file;
          I:Integer;
          Procedure Allow_More_Files( Max_Files:Byte );
            Var
              Regs:Registers;
            Begin
              With Regs do
                Begin
                  AH := $67;
                  BX := Max_Files;
                  Intr( $21,Regs );
                  If Flags And FCarry <> 0
                    Then
                      Writeln( 'Dos error : ',AX);

                End;
            End;

        Begin
          Allow_More_Files( 30 );
          For I:=1 to 30 do
            Begin
              Assign(Files[I],'DAT.'+ Chr(I DIV 10+48) + Chr(I Mod 10+48));
              Rewrite(Files[I]);
            End;
          For I:=1 to 100 do
            Close( Files[I] );
        End.


Reference:


7/16/98 4:35:36 PM
 

Last Modified: 01-SEP-99