How to save classic Delphi string to disk (and read them back)?

Question

I want to achieve a very very basic task in Delphi: to save a string to disk and load it back. It seems trivial but I had problems doing this TWICE since I upgraded to IOUti

Answer 1

Just use TStringList, until size of file < ~50-100Mb (it depends on CPU speed):

procedure ReadTextFromFile(const AFileName: string; SL: TStringList);
begin
  SL.Clear;
  SL.DefaultEncoding:=TEncoding.ANSI; // we know, that old files has this encoding
  SL.LoadFromFile(AFileName, nil); // let TStringList detect real encoding.
  // if not - it just use DefaultEncoding.
end;

procedure WriteTextToFile(const AFileName: string; const TextToWrite: string);
var
  SL: TStringList;
begin
  SL:=TStringList.Create;
  try
    ReadTextFromFile(AFileName, SL); // read all file with encoding detection
    SL.Add(TextToWrite);
    SL.SaveToFile(AFileName, TEncoding.UTF8); // write file with new encoding.
    // DO NOT SET SL.WriteBOM to False!!!
  finally
    SL.Free;
  end;
end;