__cxa_finalize and `on_exit'

[Mark Mitchell]

The GNU C library supports the BSD/SunOS-ish `on_exit' as well as
`atexit'.  A function registered with on_exit is just like one
registered with atexit, except that it (like functions registered with
__cxa_atexit) takes a parameter, and that parameter is registered at
on_exit time.

In addition, the function registered with on_exit is passed the
exit-status when exit is called.

But, __cxa_finalize doesn't know the exit-status, even when called
with NULL to indicate that the main program is exiting, so it can't
call the on_exit functions correctly.

I suggest that we mandate that __cxa_finalize is always called with a
non-NULL parameter, or that it immediately return if passed a NULL
parameter.

Let's just let exit do it's normal thing (which will include calling
__cxa_atexit-registered functions), and use __cxa_finalize only for
DSOs.

--
Mark Mitchell                   mark at codesourcery.com
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