Problem to determine if file is locked.

Hi everybody.

I use the following code to check if a file is opened by another user:

Function IsFileLocked(const fileName : String; openRead : Boolean = True;
openWrite : Boolean = True) : Boolean;
var
   chkStream     : TFileStream;
begin
    Try {[01]}
       Result := False;
       IF FileExists(fileName) Then
       begin
          IF (openRead = openWrite) Then
          begin
             chkStream := TFileStream.Create(fileName, fmOpenReadWrite OR
fmShareExclusive);
          end
          else begin
             IF openRead Then
             begin
                chkStream := TFileStream.Create(fileName, fmOpenRead OR
fmShareExclusive);
             end
             else begin
                chkStream := TFileStream.Create(fileName, fmOpenWrite OR
fmShareExclusive);
             end; {-> IF openRead Then }
          end; {-> IF (openRead = openWrite) Then }
          chkStream.Free;
       end; {<- IF FileExists(fileName) Then }
    except {[01]}
       Result := True;
       // chkStreamFree; Don't free the object here, that causes an error
    end; {[01]}
end;

Unfortunately this works not correct if I make the test on shared
directories.

The folder name is an UNC name.

If I copy from my test machine a file into the folder and check this file
the answer is as expected -> The file is not locked.

If another user on the destination machine copy a file into the folder and I
check the file from my test machine the result is wrong. I cannot open the
file exclusive allthough it is not opened by any user.

Any idea how to solve this?

Thanks in advance for any help.
Kind regards,

Ruediger Kabbasch