a synchronization issue - jusy for you guys

From: Amit (amit_t_at_chief.co.il)
Date: 06/06/04 

Date: Sun, 6 Jun 2004 15:46:18 +0200

i have a number of worker threads, getting a file name when created and
doing some processing with that file. some of the threads might get the same
file name, and in that case i want the first one who got to it to "tell" all
the other ones with that same file to wait untill its done. When it is done,
i want the next thread to "lock" the file for itself and "release" it to
others when it is done, and so on... the reason im using "" is because i
want all synchronization to be external, and NOT by file locking mechanizm.

i tried the following in my worker threads:

  hEvent := OpenEvent(EVENT_ALL_ACCESS, True, PChar(FileName));
  if hEvent = 0 then // if no one is processing that same file
right now
  begin
    hEvent := CreateEvent(nil, True, False, PChar(FileName));
  end else // Someone is processing that file, wait until its done
  begin
    WaitForSingleObject(hEvent, INFINITE);
  end;
  ..
  .. { some processing }
  ..

  SetEvent(hEvent); // Tell others im done with that file
  CloseHandle(hEvent);

but it doesnt seem to work properly.
i need some kind of named critical section or something.
ideas?

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