signaling when a file is closed

[Andrew B. Young]

If this is OT feel free to direct me elsewhere.

I need to know when a process as finished writing
a file and has closed it.  My only clue is fuser,
which somehow knows what processes have files open.

Is there a way for me to set a signal on a file's
state that lets me know when it has been closed?


Some background--

I have a MRI machine that runs GE's canned software
which writes out one new file of image data per second
in a known directory.  I need to stream this data
into another process in near-real-time.

Using [id]notify I can watch the directory and know
when a new file is created. But I need to know when
the file has been closed by the writing process such
that there is no more data to be read.

Thanks,
Andrew