Delphi Basics : Flush command

DelphiBasics

Flush
Procedure

Flushes buffered text file data to the file

System unit

procedure Flush(var FileHandle TextFile);

Description

The Flush procedure flushes unwritten text file data to disk.

The same effect can be achieved by closing the file. In fact, this is more likely to be effective, since Flush simply passes the flush request to the Operating System, which may in turn be doing its own buffering, and possibly caching.

Related commands

AssignFile		Assigns a file handle to a binary or text file
CloseFile		Closes an open file
File		Defines a typed or untyped file
TextFile		Declares a file type for storing lines of text

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Example code : Flushing after writing lines to a file

var
  myFile : TextFile;
  text   : string;

begin
  // Try to open the Test.txt file for writing to
  AssignFile(myFile, 'Test.txt');
  ReWrite(myFile);

  // Write a couple of well known words to this file
  WriteLn(myFile, 'Hello');
  WriteLn(myFile, 'World');
  Flush(myFile);

  // Close the file
  CloseFile(myFile);

  // Reopen the file for reading
  Reset(myFile);

  // Display the file contents
  while not Eof(myFile) do
  begin
    ReadLn(myFile, text);
    ShowMessage(text);
  end;

  // Close the file for the last time
  CloseFile(myFile);
end;

Show full unit code

Hello
World