SetTextBuf

Assigns an I/O buffer to a text file.

Declaration

procedure SetTextBuf(var F: Text; var Buf [ ; Size:   Word ] );

Target

Windows, Real, Proctected

Remarks

SetTextBuf should never be applied to an open file, although it can be called immediately after Reset, Rewrite, and Append.

If you call SetTextBuf on an open file once I/O operations have taken place, loss of data can result because of the change of buffer.

Pascal does not ensure that the buffer exists for the entire duration of I/O operations on the file. A common error is to install a local variable as a buffer, then use the file outside the procedure that declared the buffer.

Sample Code

{Settxtbf.PAS}
{Sample code for the SetTextBuf procedure.}

{ For Windows: }
{ uses WinCrt; }

var
  F: Text;
  Ch: Char;
  Buf: array[1..4095] of Char;  { 4K buffer }
begin
  { Get file to read from command line }
  Assign(F, ParamStr(1));
  { Bigger buffer for faster reads }
  SetTextBuf(F, Buf);
  Reset(F);
  { Dump text file onto screen }
  while not Eof(f) do
  begin
    Read(F, Ch);
    Write(Ch);
  end;
end.