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Determine if a file is open

light_bulb asked
Medium Priority
Last Modified: 2010-04-05
How can I easily determine if a file is already open before I try to open it programatically.

Specifically, my program involves displaying pdf files in Acrobat Reader.  If the user already has one the pdf file open, how can detect that?

Watch Question

Try this:

function IsFileInUse(FileName: TFileName): Boolean;
  HFileRes: HFILE;
  Result := False;
  if not FileExists(FileName) then Exit;
  HFileRes := CreateFile(PChar(FileName),
                         GENERIC_READ or GENERIC_WRITE,
  Result := (HFileRes = INVALID_HANDLE_VALUE);
  if not Result then

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Top Expert 2004

usual a try to open the file exclusive should tell you if you can do this,
if you can -> the file is not in use
if you not can -> the file is use

guess this does the suggestion of  Johnjces already,
it could be done with a TFileStream aslo

meikl ;-)
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