How to find file status?

try with TSearchRec.Attr , findFirst(), findNext()...
but I think this is only for get the read-only, hidden attribute or date and time but not sure for the rest.

I've put together a function for you that will do what you need.

//*** Returns true if key/value is successfylly written, false otherwise
//*** -Timeout must be given in seconds and indicates how long you are
//***  willing to wait for the function to complete
//*** function assumes the file exists, raises an exception if not...
function WriteINIFile(fname, key, value: string; Timeout: integer): boolean;
var f: TFileStream;
    TimeoutReached: boolean;
    StartTime: TDateTime;
    bytesWritten: integer;
    buf: string;
begin
  result:= false;
  try
    f:= TFileStream.Create(fname, fmOpenWrite, fmShareDenyWrite);
    try
      StartTime:= now;
      while (NOT result) AND (NOT TimeoutReached) do
      begin
        TimeoutReached:= (Now > (StartTime + Timeout/86400)); //86400 seconds in a day
        buf:= #13#10+key+'='+value;
        f.Seek(f.Size, soFromBeginning);
        bytesWritten:= f.Write(buf[1], Length(buf));
        result:= (bytesWritten <> 0);
        //result:= (bytesWritten <> SizeOf(buf)); --> would be more precise i.e. would return false if only part of buf is written
      end;
    except
      result:= false;
    end;
  finally
    try f.Free except end;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  WriteINIFile('c:\testing.ini', 'test','boo-hoo',60);
end;


Regards
Pierre

Just realised something:

The constructor should fall within the timeout loop because an exception will be raised if the file can not be opened in write mode (i.e. when another instance of your app is writing to the file. Change the function as follows:

//*** Returns true if key/value is successfylly written, false otherwise
//*** -Timeout must be given in seconds and indicates how long you are
//***  willing to wait for the function to complete
//*** function assumes the file exists
function WriteINIFile(fname, key, value: string; Timeout: integer): boolean;
var f: TFileStream;
    TimeoutReached: boolean;
    StartTime: TDateTime;
    bytesWritten: integer;
    buf: string;
begin
  result:= false;
  f:= nil;
  try
    StartTime:= now;
    while (NOT result) AND (NOT TimeoutReached) do
    begin
      TimeoutReached:= (Now > (StartTime + Timeout/86400)); //86400 seconds in a day
      if TimeOutReached then break;
      if f = nil then try
        f:= TFileStream.Create(fname, fmOpenWrite, fmShareDenyWrite);
        buf:= #13#10+key+'='+value;
        f.Seek(f.Size, soFromBeginning);
        bytesWritten:= f.Write(buf[1], Length(buf));
        result:= (bytesWritten <> 0);
        //result:= (bytesWritten <> SizeOf(buf)); --> would be more precise i.e. would return false if only part of buf is written
      except
        result:= false;
      end;
    end;
  finally
    try f.Free except end;
  end;
end;


NOTE: The fmShareDenyWrite parameter is only for Linux platform, it is ingored on windows platform

Regards
Pierre

Is there any way that don't use TTimer and just direct get an appropriate file status? Like
while not IsWritableStatus do
  sleep(200);
...

Hi Starkbock
Your code is absolutely working. Thank u.

I just think if add file status check before [Write To File](see below), it will be better. Just don't know how and what file status to check.


Function TryToWriteToTheFile : boolean;
var tries : integer;
      done : boolean;
Begin
 done := false;
 tries := 0;
 Repeat
  Try
    if CheckFileStatusOK then
    begin
       [Write To File]   // Do the actual write op.
       Done := true;    // We are still here - no errors - we made it.
    end;
  except
     Inc(tries);   // Nope - we got transferred the the exception handler - wait a while
     Sleep(200); // Should be enough
  end;
 Until Done or (Tries > 50);  // We have to time  out eventually, 10 seconds here...
 Result := done;