Reading a file that is currently in use.

I think the other process could not allow changing the attributes of the file to readonly until finished usage ....

no, it can...

procedure Make_File_Read_Only(FileName: string);
begin
  if not ((FileGetAttr(FileName) and faReadOnly) > 0) then
    FileSetAttr(FileName, FileGetAttr(FileName) xor faReadOnly);
end;

procedure Make_File_Not_Read_Only(FileName: string);
begin
  if ((FileGetAttr(FileName) and faReadOnly) > 0) then
    FileSetAttr(FileName, FileGetAttr(FileName) xor faReadOnly);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Make_File_Read_Only('C:\Read.txt');
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  Make_File_Not_Read_Only('C:\Read.txt');
end;

i know HOW to do that, what my question was is there a more legit, cleaner method? im not looking for code.

I don't think that changing the attribs has any effect in this situation.

There are 2 ways to solve the problem, I think:

(1) The other process must have a handle to the file open. You could try to find the handle value and call DuplicateHandle. This way you should get access to the file content.

(2) In XP/2003 drivers are able to open locked files (by using a special flag).

changing the attributes causes the writing process to error out on the writing function, therefore closing its handle (apparently).

anyways, thanks for your reply. what are you drivers that are able to open locked files?

oh, i understand now, thanks!